subject:(out of autoclave)

1. Komus, Alastair. Outgassing Of Out-Of-Autoclave Composite Primary Structures For Small Satellites.

Degree: MS, Space Studies, 2017, University of North Dakota

URL: https://commons.und.edu/theses/2254

► Out-of-autoclave vacuum-bagged-only (VBO) processing is capable of producing lower cost composite primary structures for small satellites than autoclave processing. However, the outgassing performance of… (more)

Subjects/Keywords: Composites; Outgassing; Out-of-Autoclave; Small Satellites

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APA (6^th Edition):

Komus, A. (2017). Outgassing Of Out-Of-Autoclave Composite Primary Structures For Small Satellites. (Masters Thesis). University of North Dakota. Retrieved from https://commons.und.edu/theses/2254

Chicago Manual of Style (16^th Edition):

Komus, Alastair. “Outgassing Of Out-Of-Autoclave Composite Primary Structures For Small Satellites.” 2017. Masters Thesis, University of North Dakota. Accessed March 05, 2021. https://commons.und.edu/theses/2254.

MLA Handbook (7^th Edition):

Komus, Alastair. “Outgassing Of Out-Of-Autoclave Composite Primary Structures For Small Satellites.” 2017. Web. 05 Mar 2021.

Vancouver:

Komus A. Outgassing Of Out-Of-Autoclave Composite Primary Structures For Small Satellites. [Internet] [Masters thesis]. University of North Dakota; 2017. [cited 2021 Mar 05]. Available from: https://commons.und.edu/theses/2254.

Council of Science Editors:

Komus A. Outgassing Of Out-Of-Autoclave Composite Primary Structures For Small Satellites. [Masters Thesis]. University of North Dakota; 2017. Available from: https://commons.und.edu/theses/2254

University of Southern California

2. Grunenfelder, Lessa Kay. Defect control in vacuum bag only processing of composite prepregs.

Degree: PhD, Materials Science, 2012, University of Southern California

URL: http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll3/id/106508/rec/1811

► Composite parts for commercial aircraft are traditionally manufactured using high-pressure autoclave processing of prepregs (carbon fiber pre-impregnated with epoxy resin). In recent decades, however, the… (more)

▼ Composite parts for commercial aircraft are traditionally manufactured using high-pressure autoclave processing of prepregs (carbon fiber pre-impregnated with epoxy resin). In recent decades, however, the use of composite parts for aircraft has increased, and aircraft markets have grown, creating pressure to increase production rates. To meet the growing demand for composite aircraft parts and to allow for the production of large composite components (i.e. wings and fuselage) alternative processing methods will be required. There are several drawbacks to autoclave processing, including a large capital investment, long cycle time, high cost of the nitrogen gas used to pressurize the vessel, size limitations, and poor energy efficiency. New out-of-autoclave processing methods have been developed to address these issues. One such method is vacuum-bag-only (VBO) processing of prepregs, a technique which uses atmospheric pressure alone to consolidate parts. ❧ VBO processing presents a potential solution for the manufacture of larger parts at faster rates using conventional layup and placement tools. However, before VBO methods can be used on primary structure, the quality of VBO processed parts must be shown to be equivalent to that of autoclave cured parts. The elimination of high external pressures during the cure cycle removes safeguards in the manufacturing process, resulting in the need for strict protocols in the layup and cure of VBO parts. To assess the feasibility of VBO processing for aerospace components a systematic study of the effect of process parameters on the quality of VBO parts is essential. Specifically, the mechanisms of void formation and growth in prepreg-processed carbon fiber composites are not well understood. The purpose of this work is to examine the potential causes of voids, to develop a complete understanding of the mechanisms of void formation. This knowledge will aid in the production of higher quality parts, and help to determine the feasibility of low-pressure VBO processing for large-scale structural components. ❧ As a starting point, carbon fiber/epoxy test laminates were manufactured using vacuum bag only methods as well as traditional autoclave cure cycles. Cured laminates were tested using aerospace qualification standards. Tests were performed on dry laminates as well as laminates that had been hot/wet conditioned. Mechanical properties were shown to be equivalent in vacuum bag only and autoclave processed laminates, and values for all test panels and test conditions exceeded the required level for structural aerospace applications. ❧ Cure cycle optimization was carried out to further improve the properties of out-of-autoclave processed parts. Variations in hold time and temperature were investigated for the first temperature dwell of the cure cycle. Several test panels were fabricated with a range of processing times and temperatures. Cured laminates were characterized for compaction (thickness), void content, and surface finish. Resin rheological properties were also examined.… Advisors/Committee Members: Nutt, Steven R. (Committee Chair), Malmstadt, Noah (Committee Member), Povinelli, Michelle L. (Committee Member).

Subjects/Keywords: composites; voids; porosity; manufacturing; out-of-autoclave

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APA (6^th Edition):

Grunenfelder, L. K. (2012). Defect control in vacuum bag only processing of composite prepregs. (Doctoral Dissertation). University of Southern California. Retrieved from http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll3/id/106508/rec/1811

Chicago Manual of Style (16^th Edition):

Grunenfelder, Lessa Kay. “Defect control in vacuum bag only processing of composite prepregs.” 2012. Doctoral Dissertation, University of Southern California. Accessed March 05, 2021. http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll3/id/106508/rec/1811.

MLA Handbook (7^th Edition):

Grunenfelder, Lessa Kay. “Defect control in vacuum bag only processing of composite prepregs.” 2012. Web. 05 Mar 2021.

Vancouver:

Grunenfelder LK. Defect control in vacuum bag only processing of composite prepregs. [Internet] [Doctoral dissertation]. University of Southern California; 2012. [cited 2021 Mar 05]. Available from: http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll3/id/106508/rec/1811.

Council of Science Editors:

Grunenfelder LK. Defect control in vacuum bag only processing of composite prepregs. [Doctoral Dissertation]. University of Southern California; 2012. Available from: http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll3/id/106508/rec/1811

3. Serrano, Léonard. Systèmes époxyde : cuisson hors autoclave et basse température : Epoxy systems : out-of-autoclave and low temperature curing.

Degree: Docteur es, Génie mécanique, mécanique des matériaux, 2018, Université Toulouse III – Paul Sabatier

URL: http://www.theses.fr/2018TOU30007

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Les principaux enjeux de la fabrication de pièces en matériaux composites (coût, temps de fabrication, performances,...) sont intimement liés aux moyens de mise en oeuvre,… (more)

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Les principaux enjeux de la fabrication de pièces en matériaux composites (coût, temps de fabrication, performances,...) sont intimement liés aux moyens de mise en oeuvre, principalement les autoclaves; qui engendrent non seulement des coûts très élevés en termes d'installation et d'entretien, mais limitent également les cadences de production à cause de la longueur des cycles. Afin de réduire cette dépendance, des procédés de fabrication hors autoclave ont été envisagés (Quickstep, Roctool, VARTM, VBO...) entrainant par conséquent des modifications dans la conception des matériaux destinés à ces procédés (cinétique, rhéologie, façon dont sont imprégnées les fibres...). Afin de limiter les changements en termes de procédé de fabrication, de matières premières, de produits d'environnement et de conditions de mise en oeuvre, c'est sur le procédé Vacuum Bag Only que porte cette étude. Plusieurs développement de semi-produits ces dernières années ont permis d'augmenter la robustesse de ce procédé de fabrication, palliant ainsi à cette absence de pression externe durant la cuisson en étuve. Il reste toutefois à démontrer la viabilité de ces produits par rapport à leur mise en oeuvre, à comprendre les mécanismes d'extraction de l'air et à estimer les propriétés mécaniques atteignables par rapport à leur équivalent autoclave.

The main issues concerning composite part manufacturing (cost, manufacturing time, mechanical performances, etc.) are closely linked to the means of curing, mainly autoclaves; which do not only generate very high installation and maintenance costs, but also limit production rates because of the length of the cycles. In order to reduce this dependence, non-autoclave manufacturing processes have been envisaged (Quickstep, Roctool, VARTM, VBO ...) therefore leading to modifications in the design of the materials intended for these processes (including kinetics, rheology, fiber impregnation methods). In order to limit the changes in terms of manufacturing process, raw materials, environment products and implementation conditions, this study is based on the Vacuum Bag Only process. Several semi-product developments in recent years have made it possible to increase the robustness of this manufacturing process, thereby overcoming the lack of external pressure during an oven cure. However, the viability of these products in relation to their implementation still needs to be demonstrated, as well as the understanding of the air removal mechanisms and the estimation of the achievable mechanical properties compared to their autoclave counterpart.

Advisors/Committee Members: Olivier, Philippe (thesis director), Cinquin, Jacques (thesis director).

Subjects/Keywords: Epoxy; Formulation; Chimie; Composites; Hors autoclave; Epoxy; Formulation; Chemistry; Composites; Out-of-autoclave

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APA (6^th Edition):

Serrano, L. (2018). Systèmes époxyde : cuisson hors autoclave et basse température : Epoxy systems : out-of-autoclave and low temperature curing. (Doctoral Dissertation). Université Toulouse III – Paul Sabatier. Retrieved from http://www.theses.fr/2018TOU30007

Chicago Manual of Style (16^th Edition):

Serrano, Léonard. “Systèmes époxyde : cuisson hors autoclave et basse température : Epoxy systems : out-of-autoclave and low temperature curing.” 2018. Doctoral Dissertation, Université Toulouse III – Paul Sabatier. Accessed March 05, 2021. http://www.theses.fr/2018TOU30007.

MLA Handbook (7^th Edition):

Serrano, Léonard. “Systèmes époxyde : cuisson hors autoclave et basse température : Epoxy systems : out-of-autoclave and low temperature curing.” 2018. Web. 05 Mar 2021.

Vancouver:

Serrano L. Systèmes époxyde : cuisson hors autoclave et basse température : Epoxy systems : out-of-autoclave and low temperature curing. [Internet] [Doctoral dissertation]. Université Toulouse III – Paul Sabatier; 2018. [cited 2021 Mar 05]. Available from: http://www.theses.fr/2018TOU30007.

Council of Science Editors:

Serrano L. Systèmes époxyde : cuisson hors autoclave et basse température : Epoxy systems : out-of-autoclave and low temperature curing. [Doctoral Dissertation]. Université Toulouse III – Paul Sabatier; 2018. Available from: http://www.theses.fr/2018TOU30007

University of Delaware

4. Zhang, Danning. Void consolidation of thermoplastic composites via non-autoclave processing.

Degree: PhD, University of Delaware. ǂb Department of Materials Science and Engineering, 2017, University of Delaware

URL: http://udspace.udel.edu/handle/19716/23026

► High quality continuous fiber reinforced thermoplastic composite materials can be obtained with autoclave processing that utilizes vacuum and high levels of positive pressure to achieve… (more)

▼ High quality continuous fiber reinforced thermoplastic composite materials can be obtained with autoclave processing that utilizes vacuum and high levels of positive pressure to achieve very low void content materials. Due to the high cost of autoclave, there is a strong demand to develop cost effective out of autoclave (OOA) alternatives that provide equivalent properties. Oven vacuum bag (OVB) processing is inherently low cost and scalable to large part manufacturing. One of the most important criteria to achieve autoclave equivalent properties is void reduction. Preliminary consolidation experiments achieved void free thin AS4/APC2 carbon PEEK thermoplastic laminates in the OVB processing. However, the methods and the mechanisms for void reduction are not fully understood. The goal of this research is to develop a fundamental understanding of the void reduction mechanisms and develop process models that can be used to design and optimize the OVB processing cycle for thermoplastic laminates of varying thickness and in-plane dimensions. ☐ The microstructure of the voids in AS4/APC2 carbon PEEK thermoplastic prepreg is critical to the initial condition of void reduction and the understanding of the void reduction mechanism. Spherical voids were assumed based on the 2D characterization in the literature. In this study, high resolution 3D X-ray micro-CT was employed to obtain 3D information of voids in a large volume of prepreg tape. Representative properties including void content, geometry and dimensions were obtained through statistical study. The statistical representative volume element (SRVE) of the void microstructure was determined. The majority of the voids were found to be rod-like with aspect ratio from 2 to 150 and finite lengths smaller than 1 mm. The voids are encapsulated in the prepreg tape and do not form porous pathways along the fiber direction. ☐ Due to the rough surfaces of the thermoplastic prepreg tapes, porous interlayer regions are formed when prepreg tapes are stacked, which is another important property that may affect the void reduction. With a 1D flow experimental set-up, the product of the in-plane air permeability and thickness (Kh) of a wide range of lay-up configurations of AS4/APC2 before and after processing were investigated. The interlayer permeability from the raw tape lay-ups is about 1-2 orders higher than the reported permeability of some partially impregnated thermosetting prepreg designed for vacuum bag processing. The interlayer permeability exhibits directional dependency, and 2D rotation transformation matrix can be used for predicting the Khs of different lay-ups. Different lay-ups show different extent of reduction with the increasing temperature and dwell time during processing. Fiber –fiber contacts limit the contact between layers and prevents significant drop of the permeability during processing. ☐ With the encapsulated voids and highly viscous resin in the AS4/APC2 prepreg tape, and vacuum bag pressure, the driving force for void reduction can only be provided by… Advisors/Committee Members: Gillespie, John W..

Subjects/Keywords: Applied sciences; Modeling; Out of autoclave; Permeability; Processing; Thermoplastic composites; Voids

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APA (6^th Edition):

Zhang, D. (2017). Void consolidation of thermoplastic composites via non-autoclave processing. (Doctoral Dissertation). University of Delaware. Retrieved from http://udspace.udel.edu/handle/19716/23026

Chicago Manual of Style (16^th Edition):

Zhang, Danning. “Void consolidation of thermoplastic composites via non-autoclave processing.” 2017. Doctoral Dissertation, University of Delaware. Accessed March 05, 2021. http://udspace.udel.edu/handle/19716/23026.

MLA Handbook (7^th Edition):

Zhang, Danning. “Void consolidation of thermoplastic composites via non-autoclave processing.” 2017. Web. 05 Mar 2021.

Vancouver:

Zhang D. Void consolidation of thermoplastic composites via non-autoclave processing. [Internet] [Doctoral dissertation]. University of Delaware; 2017. [cited 2021 Mar 05]. Available from: http://udspace.udel.edu/handle/19716/23026.

Council of Science Editors:

Zhang D. Void consolidation of thermoplastic composites via non-autoclave processing. [Doctoral Dissertation]. University of Delaware; 2017. Available from: http://udspace.udel.edu/handle/19716/23026

Luleå University of Technology

5. Murtagh, Timothy. Manufacturing Launch Vehicle Adapter Structures Using Out-of-Autoclave Technique.

Degree: 2014, Luleå University of Technology

URL: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-59235

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RUAG Space in Linköping is the world’s biggest supplier of adapter structures and separationsystems for satellites. The purpose of an adapter structures is to… (more)

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RUAG Space in Linköping is the world’s biggest supplier of adapter structures and separationsystems for satellites. The purpose of an adapter structures is to provide some means bywhich the satellite can be attached to the rocket. Some of the adapters are made fromcarbon fiber reinforced plastic and the object of this thesis is to investigate alternativeproduction methods and to construct and test a prototype adapter made with chosenmethod.The selected method (vacuum bag only) was used to manufacture a prototype between thediameters 298 mm and 437mm with a height of 104 mm using VTM264 epoxy reinforcedwith 5HS (3K) 283 g/m2 carbon fiber weave supplied by CYTEC Ind. Materials. The adapterprototype was designed and simulated using Nastran Software and the lay-up chosen so thatit could support a 200 kg satellite mounted 450 mm above the upper edge of the adapter.Several test plates were manufactured using an identical matrix but a different weave toestablish cure characteristics and optimal design of the edge dams so that the void contentcould be kept at a minimum. The best edge-dam design was found to consist of generalsealant, unperforated film and woven glass fiber. The finished adapter prototype wasdetermined to have a fiber volume fraction of 49.7 % and a void content of roughly 1.5-2 %in the radii and 0.5 % in the flat areas which is not far from the current material whichtolerates voids up to 0.5 %. The adapter also showed a slight thickening effect in the concaveradius and a thinning effect in the convex; these were expected and are also present tosome extent in current structures.The adapter was installed in the testing rig where it was exposed to some of the loadsrepresenting the design criteria used. The test loads were increased all the way to failureand the fatal load in a combined (compressive and lateral) load was determined to beroughly 87 kN which is several times above the required load limit.The material was also tested in respect to ILSS and 4-point bending at Exova in Linköpingwhere the initial results show a 9.7 % increase in interlaminar shear strength and a 28.5 %decrease in flexural strength compared to current materialOverall the results are very promising, indicating a high potential in the selected method.However, further studies should be performed to optimize the manufacturing method andmore extensive tests should be carried out on more material systems.

Validerat; 20141126 (global_studentproject_submitter)

Subjects/Keywords: Technology; Composites; Carbon Fibre; Autoclave; Out-of-Autoclave; VBO; Prepreg; Laminate; Launch Vehicle Adapter; Oven curing; Teknik

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APA (6^th Edition):

Murtagh, T. (2014). Manufacturing Launch Vehicle Adapter Structures Using Out-of-Autoclave Technique. (Thesis). Luleå University of Technology. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-59235

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Murtagh, Timothy. “Manufacturing Launch Vehicle Adapter Structures Using Out-of-Autoclave Technique.” 2014. Thesis, Luleå University of Technology. Accessed March 05, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-59235.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Murtagh, Timothy. “Manufacturing Launch Vehicle Adapter Structures Using Out-of-Autoclave Technique.” 2014. Web. 05 Mar 2021.

Vancouver:

Murtagh T. Manufacturing Launch Vehicle Adapter Structures Using Out-of-Autoclave Technique. [Internet] [Thesis]. Luleå University of Technology; 2014. [cited 2021 Mar 05]. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-59235.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Murtagh T. Manufacturing Launch Vehicle Adapter Structures Using Out-of-Autoclave Technique. [Thesis]. Luleå University of Technology; 2014. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-59235

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Delaware

6. Cender, Thomas A. Process analysis of manufacturing composites structures with vacuum-bag-only prepregs: quantifying partial resin impregnation and its effect on gas evacuation.

Degree: PhD, University of Delaware, Department of Mechanical Engineering, 2017, University of Delaware

URL: http://udspace.udel.edu/handle/19716/22644

► Vacuum bag-only processes, used in the manufacture of composite structures (fiber reinforced polymer), are inexpensive alternatives to similar high pressure pro- cesses which can reliably… (more)

▼ Vacuum bag-only processes, used in the manufacture of composite structures (fiber reinforced polymer), are inexpensive alternatives to similar high pressure pro- cesses which can reliably produce highly consolidated - high fiber volume fraction, low void content - composite laminates. Prepregs – fiber plies, pre-impregnated with resin (thermoset or thermoplastic) – are processed with elevated temperature and pressure (applied normal to the laminate), which consolidates and cures the prepregs to form the composite structure. Research within the last decade has proven that low void content composite laminates can be produced using prepregs with a vacuum bag only process (in ambient atmosphere) if the prepregs are only partially impregnated with resin. ☐ Open porosity (non-impregnated cross-sections) of the fiber architecture, serves as air evacuation pathways, which allows vacuum pressure applied at the boundaries of the laminated structure to evacuate any gases before becoming entrapped in the resin. The nature of resin distribution (and redistribution), evolution of open porosity, and it’s effect on gas evacuation - which intrinsically defines the material properties pertaining to processing and process outcome - is poorly understood. This dissertation pursues a framework and methodology to characterize the relationship between resin saturation and macroscopic gas evacuation properties (permeability, porosity, and Klinkenberg effects), as well as the near-microscopic flow of resin during consolidation. ☐ This dissertation introduces an in-situ resin visualization method used to (i) model the dual scale resin impregnation as a function of pressure and temperature, (ii) observe and model the movement of bubbles which travel with the resin toward evacu- ated air pathways,and (iii) quantify the surface saturation, which is used to characterize gas permeability as it changes with resin saturation. ☐ This surface visualization method demonstrates that resin flow observed to strongly follow a dual scale flow pattern. A flow model is introduced to describe the two observed flow stages: inter-fiber tow flow and intra-tow flow. By matching the experimental data with the model, values of permeability are estimated from inter-tow pores and intra-tow pores. ☐ Using the same visualization technique, the focus is changed to track bubbles flowing in the resin. Bubbles are observed to emerge through pinholes and flow with the resin through inter-tow channels. A key finding of this study is that tunable process parameters, such as pressure and temperature, are less important for successful bubble removal as compared to the initial state of resin impregnation in the prepreg. Prepregs with high resin impregnation will not be able to vent bubbles, but with sufficiently low resin impregnation, bubbles may escape into air pathways. Small Capillary number theory (i.e. Ca < 0.01) was shown to under predict the relative velocity of bubbles, suggesting that surface tension does not significantly contribute to the drag force on bubbles. ☐ Gas… Advisors/Committee Members: Advani, Suresh G..

Subjects/Keywords: Applied sciences; Composite materials; Gas evacuation; Impregnation; Out-of-Autoclave; Permeability; Prepreg

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APA (6^th Edition):

Cender, T. A. (2017). Process analysis of manufacturing composites structures with vacuum-bag-only prepregs: quantifying partial resin impregnation and its effect on gas evacuation. (Doctoral Dissertation). University of Delaware. Retrieved from http://udspace.udel.edu/handle/19716/22644

Chicago Manual of Style (16^th Edition):

Cender, Thomas A. “Process analysis of manufacturing composites structures with vacuum-bag-only prepregs: quantifying partial resin impregnation and its effect on gas evacuation.” 2017. Doctoral Dissertation, University of Delaware. Accessed March 05, 2021. http://udspace.udel.edu/handle/19716/22644.

MLA Handbook (7^th Edition):

Cender, Thomas A. “Process analysis of manufacturing composites structures with vacuum-bag-only prepregs: quantifying partial resin impregnation and its effect on gas evacuation.” 2017. Web. 05 Mar 2021.

Vancouver:

Cender TA. Process analysis of manufacturing composites structures with vacuum-bag-only prepregs: quantifying partial resin impregnation and its effect on gas evacuation. [Internet] [Doctoral dissertation]. University of Delaware; 2017. [cited 2021 Mar 05]. Available from: http://udspace.udel.edu/handle/19716/22644.

Council of Science Editors:

Cender TA. Process analysis of manufacturing composites structures with vacuum-bag-only prepregs: quantifying partial resin impregnation and its effect on gas evacuation. [Doctoral Dissertation]. University of Delaware; 2017. Available from: http://udspace.udel.edu/handle/19716/22644

Cal Poly

7. Matson, Trenton John. A Comparison of Crushing Parameters of Graphite Composite Thin-Walled Cylinders Cured in Low and High Pressures.

Degree: MS, Aerospace Engineering, 2019, Cal Poly

URL: https://digitalcommons.calpoly.edu/theses/2084 ; 10.15368/theses.2019.88

► Out-of-Autoclave (OoA) processes for manufacturing aerospace-grade parts needs to be better understood to further the development and success of industries that are manufacturing reusable… (more)

Subjects/Keywords: composite; tube; out-of-autoclave; energy absorption; FEA; axial compression; Structures and Materials

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APA (6^th Edition):

Matson, T. J. (2019). A Comparison of Crushing Parameters of Graphite Composite Thin-Walled Cylinders Cured in Low and High Pressures. (Masters Thesis). Cal Poly. Retrieved from https://digitalcommons.calpoly.edu/theses/2084 ; 10.15368/theses.2019.88

Chicago Manual of Style (16^th Edition):

Matson, Trenton John. “A Comparison of Crushing Parameters of Graphite Composite Thin-Walled Cylinders Cured in Low and High Pressures.” 2019. Masters Thesis, Cal Poly. Accessed March 05, 2021. https://digitalcommons.calpoly.edu/theses/2084 ; 10.15368/theses.2019.88.

MLA Handbook (7^th Edition):

Matson, Trenton John. “A Comparison of Crushing Parameters of Graphite Composite Thin-Walled Cylinders Cured in Low and High Pressures.” 2019. Web. 05 Mar 2021.

Vancouver:

Matson TJ. A Comparison of Crushing Parameters of Graphite Composite Thin-Walled Cylinders Cured in Low and High Pressures. [Internet] [Masters thesis]. Cal Poly; 2019. [cited 2021 Mar 05]. Available from: https://digitalcommons.calpoly.edu/theses/2084 ; 10.15368/theses.2019.88.

Council of Science Editors:

Matson TJ. A Comparison of Crushing Parameters of Graphite Composite Thin-Walled Cylinders Cured in Low and High Pressures. [Masters Thesis]. Cal Poly; 2019. Available from: https://digitalcommons.calpoly.edu/theses/2084 ; 10.15368/theses.2019.88

Delft University of Technology

8. Choudhary, Abhas (author). Thermal deconsolidation of thermoplastic prepreg tapes during Laser-Assisted Fiber Placement.

Degree: 2019, Delft University of Technology

URL: http://resolver.tudelft.nl/uuid:d363b989-f29a-467f-a0dd-dc5e62680546

► The automation of thermoplastic composite production and the drive towards out-of-autoclave processes, is of great relevance in the aerospace and lightweight composite structures industry. Hence,… (more)

▼ The automation of thermoplastic composite production and the drive towards out-of-autoclave processes, is of great relevance in the aerospace and lightweight composite structures industry. Hence, there is a crucial need for developing the current state of material and process understanding, in order to increase the technology readiness levels of automated, out-of-autoclave production processes. Laser assisted fiber placement (LAFP) is a well-researched, automated production process which has been used in developing various thermoplastic composite demonstrators. Theoretically, this process does not require an autoclave consolidation cycle. However, one of the remaining challenge in the process, is the relatively high void content in the produced laminates (>1%). This high void content is impeding the development of thermoplastic composite structures with mechanical strength comparable to structures produced through traditional processing techniques, such as an autoclave. One of the main reasons for the remaining void content in the laminates after consolidation by the roller, is thermal deconsolidation during the rapid heating phase of the process. This is a very less researched aspect of LAFP, due to which, not much is known about the changes that the incoming material undergoes, due to the rapid laser heating and which mechanisms govern these changes. Due to this, thermal deconsolidation is also not included in predictive models for the process and hence the accuracy of these models in predicting the final part quality is poor. Therefore, this research focuses on gaining a better understanding of thermal deconsolidation, in the context of rapid laser heating during LAFP, through experimental investigation.The influence of five process variables was studied in this work: heating time, heated spot length, cooling rate, nip point temperature and the polymer type in carbon-fiber reinforced thermoplastic pre-impregnated (prepreg) tapes. The deconsolidated state of prepreg tape specimens was captured after rapid laser heating and the changes were characterized. The main results revealed that thermal deconsolidation due to rapid laser heating is governed by multiple mechanisms. Some previously unreported and non-intuitive results were observed in the material response to rapid laser heating, which are suspected to have a strong influence on the quality of the laminates produced through LAFP. Based on a qualitative and quantitative study of the influence of studied process variables on thermal deconsolidation, some mechanisms were identified and later verified with confirmatory experiments. The results of this study can be used as a starting point to develop predictive models for estimating the deconsolidated state of thermoplastic prepreg tapes, at the end of the rapid heating phase, in future work. Various topics for further research prevail. These include but are not limited to: studying the influence of tool temperature on the deconsolidation response of the prepreg material, evaluation of the deconsolidated state… Advisors/Committee Members: Teuwen, Julie (mentor), Delft University of Technology (degree granting institution).

Subjects/Keywords: Thermoplastic; Prepreg; Deconsolidation; Laser Assisted Fiber Placement (LAFP); In-situ consolidation; Out-of-autoclave

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APA (6^th Edition):

Choudhary, A. (. (2019). Thermal deconsolidation of thermoplastic prepreg tapes during Laser-Assisted Fiber Placement. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:d363b989-f29a-467f-a0dd-dc5e62680546

Chicago Manual of Style (16^th Edition):

Choudhary, Abhas (author). “Thermal deconsolidation of thermoplastic prepreg tapes during Laser-Assisted Fiber Placement.” 2019. Masters Thesis, Delft University of Technology. Accessed March 05, 2021. http://resolver.tudelft.nl/uuid:d363b989-f29a-467f-a0dd-dc5e62680546.

MLA Handbook (7^th Edition):

Choudhary, Abhas (author). “Thermal deconsolidation of thermoplastic prepreg tapes during Laser-Assisted Fiber Placement.” 2019. Web. 05 Mar 2021.

Vancouver:

Choudhary A(. Thermal deconsolidation of thermoplastic prepreg tapes during Laser-Assisted Fiber Placement. [Internet] [Masters thesis]. Delft University of Technology; 2019. [cited 2021 Mar 05]. Available from: http://resolver.tudelft.nl/uuid:d363b989-f29a-467f-a0dd-dc5e62680546.

Council of Science Editors:

Choudhary A(. Thermal deconsolidation of thermoplastic prepreg tapes during Laser-Assisted Fiber Placement. [Masters Thesis]. Delft University of Technology; 2019. Available from: http://resolver.tudelft.nl/uuid:d363b989-f29a-467f-a0dd-dc5e62680546

Université de Bordeaux I

9. Xu, Chan. Étude et simulation numérique d’un procédé de cuisson rapide pour l’élaboration de matériaux composites à matrice thermodurcissable : Numerical modeling and optimization of micro and nano twist-pin connectors.

Degree: Docteur es, Mécanique et ingénierie, 2013, Université de Bordeaux I

URL: http://www.theses.fr/2013BOR14895

►

L’élaboration de composites en cuisson autoclave est un procédé bien maîtrisé maisles cycles de cuisson peuvent être très longs, en particulier dans le cas de… (more)

▼

L’élaboration de composites en cuisson autoclave est un procédé bien maîtrisé maisles cycles de cuisson peuvent être très longs, en particulier dans le cas de préimprégnésaéronautiques. L’objectif de ce travail de thèse est d’étudier la possibilité de diminuer letemps des cycles de polymérisation pour la fabrication de composites stratifiés minces àl’aide d’un procédé de cuisson rapide. Des essais de caractérisation ont permis de définirles grandeurs thermodynamiques du préimprégné carbone/époxy qui a servi de base ànotre étude ainsi que les paramètres du modèle cinétique de la résine. Une simulationnumérique du procédé de cuisson, basée sur une modélisation des couplages desphénomènes chimiques (polymérisation de la résine), thermiques (transferts de chaleuravec prise en compte de l’exothermie de la réaction) et mécaniques (formation decontraintes et déformations résiduelles) induits par le procédé, a été développée dans lebut d’optimiser les cycles de polymérisation. La caractérisation mécanique des matériauxélaborés à partir d’un dispositif de cuisson rapide mis au point au Laboratoire a permis dedémontrer que nous n’avions pas de pertes de caractéristiques par rapport aux piècesélaborées en autoclave.

The autoclave polymerization is the bottleneck of the production flux for largepublic parts, hence the speedy polymerization process emerges to improve the productionratio. The objective is to study the possibility of reducing the cycle time of polymerizationfor the production of thin composite laminates using a fast cure process out-of-autoclave.Specific or standard chemical and mechanical characterization tests had been designed inorder to capture the expected characteristics for the model simulation and validate thesimulation results. According to the values obtained, an analysis based on the finiteelement technique is developed to simulate the speedy curing process of epoxy resincomposite. The analysis relates the cure temperature to the thermal, chemical and physicalprocesses occurring in the thin composite part during cure. Included in the analysis are theeffects such as the heat generation due to exothermic chemical reactions. For a specifiedcure cycle, the model could be used to calculate the temperature distribution, the degree ofcure of the resin inside the composite part as well as predict the residual curing stressesand the strains of the cured composite parts.Keywords :

Advisors/Committee Members: Perry, Nicolas (thesis director), Lacoste, Éric (thesis director).

Subjects/Keywords: Polymérisation; Cuisson rapide; Composite, Carbone/époxy; Hors autoclave; Modélisation; Simulation; Contraintes et déformations résiduelles; Polymerization; Quick cure; Composite; Carbon/epoxy; Out of autoclave; Modeling; Simulation; Residual stresses and strains

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APA (6^th Edition):

Xu, C. (2013). Étude et simulation numérique d’un procédé de cuisson rapide pour l’élaboration de matériaux composites à matrice thermodurcissable : Numerical modeling and optimization of micro and nano twist-pin connectors. (Doctoral Dissertation). Université de Bordeaux I. Retrieved from http://www.theses.fr/2013BOR14895

Chicago Manual of Style (16^th Edition):

Xu, Chan. “Étude et simulation numérique d’un procédé de cuisson rapide pour l’élaboration de matériaux composites à matrice thermodurcissable : Numerical modeling and optimization of micro and nano twist-pin connectors.” 2013. Doctoral Dissertation, Université de Bordeaux I. Accessed March 05, 2021. http://www.theses.fr/2013BOR14895.

MLA Handbook (7^th Edition):

Xu, Chan. “Étude et simulation numérique d’un procédé de cuisson rapide pour l’élaboration de matériaux composites à matrice thermodurcissable : Numerical modeling and optimization of micro and nano twist-pin connectors.” 2013. Web. 05 Mar 2021.

Vancouver:

Xu C. Étude et simulation numérique d’un procédé de cuisson rapide pour l’élaboration de matériaux composites à matrice thermodurcissable : Numerical modeling and optimization of micro and nano twist-pin connectors. [Internet] [Doctoral dissertation]. Université de Bordeaux I; 2013. [cited 2021 Mar 05]. Available from: http://www.theses.fr/2013BOR14895.

Council of Science Editors:

Xu C. Étude et simulation numérique d’un procédé de cuisson rapide pour l’élaboration de matériaux composites à matrice thermodurcissable : Numerical modeling and optimization of micro and nano twist-pin connectors. [Doctoral Dissertation]. Université de Bordeaux I; 2013. Available from: http://www.theses.fr/2013BOR14895

University of Southern California

10. Thomas, Shad. Vacuum-bag-only processing of composites.

Degree: PhD, Materials Science, 2009, University of Southern California

URL: http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/147292/rec/7802

► Ultrasonic imaging in the C-scan mode in conjunction with the amplitude of the reflected signal was used to measure flow rates of an epoxy resin… (more)

▼ Ultrasonic imaging in the C-scan mode in conjunction with the amplitude of the reflected signal was used to measure flow rates of an epoxy resin film penetrating through the thickness of single layers of woven carbon fabric. Assemblies, comprised of a single layer of fabric and film, were vacuum-bagged and ultrasonically scanned in a water tank during impregnation at 50°C, 60°C, 70°C, and 80°C. Measured flow rates were plotted versus inverse viscosity to determine the permeability in the thin film, non-saturated system. The results demonstrated that ultrasonic imaging in the C-scan mode is an effective method of measuring z-direction resin flow through a single layer of fabric. The permeability values determined in this work were consistent with permeability values reported in the literature. Capillary flow was not observed at the temperatures and times required for pressurized flow to occur. The flow rate at 65°C was predicted from the linear plot of flow rate versus inverse viscosity.; The effects of fabric architecture on through-thickness flow rates during impregnation of an epoxy resin film were measured by ultrasonic imaging. Multilayered laminates comprised of woven carbon fabrics and epoxy films (prepregs) were fabricated by vacuum-bagging. Ultrasonic imaging was performed in a heated water tank (65°C) during impregnation. Impregnation rates showed a strong dependence on fabric architecture, despite similar areal densities. Impregnation rates are directly affected by inter-tow spacing and tow nesting, which depend on fabric architecture, and are indirectly affected by areal densities.; A new method of predicting resin infusion rates in prepreg and resin film infusion processes was proposed. The Stokes equation was used to derive an equation to predict the impregnation rate of laminates as a function of fabric architecture. Flow rate data previously measured by ultrasound was analyzed with the new equation and the Kozeny-Carman equation. A fiber interaction parameter was determined as a function of fabric architecture. The derived equation is straight-forward to use, unlike the Kozeny-Carman equation. The results demonstrated that the newly derived equation can be used to predict the resin infusion rate of multilayer laminates. Advisors/Committee Members: Nutt, Steven R. (Committee Chair), Sammis, Charles G. (Committee Member), Armani, Andrea M. (Committee Member).

Subjects/Keywords: VBO; out-of-autoclave; ultrasound imaging; prepreg; resin film infusion

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APA (6^th Edition):

Thomas, S. (2009). Vacuum-bag-only processing of composites. (Doctoral Dissertation). University of Southern California. Retrieved from http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/147292/rec/7802

Chicago Manual of Style (16^th Edition):

Thomas, Shad. “Vacuum-bag-only processing of composites.” 2009. Doctoral Dissertation, University of Southern California. Accessed March 05, 2021. http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/147292/rec/7802.

MLA Handbook (7^th Edition):

Thomas, Shad. “Vacuum-bag-only processing of composites.” 2009. Web. 05 Mar 2021.

Vancouver:

Thomas S. Vacuum-bag-only processing of composites. [Internet] [Doctoral dissertation]. University of Southern California; 2009. [cited 2021 Mar 05]. Available from: http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/147292/rec/7802.

Council of Science Editors:

Thomas S. Vacuum-bag-only processing of composites. [Doctoral Dissertation]. University of Southern California; 2009. Available from: http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/147292/rec/7802

Georgia Tech

11. Ziegenbein, Jordan Michael. Magnetic clamping structures for the consolidation of composite laminates.

Degree: MS, Mechanical Engineering, 2011, Georgia Tech

URL: http://hdl.handle.net/1853/43588

► Vacuum bags in conjunction with autoclaves are currently employed to generate the consolidation pressures and temperatures required to manufacture aerospace level composites. As the scale… (more)

Subjects/Keywords: Magnetic rubber; Magnetorheological materials; Out-of-autoclave; Magnetic forces; Electromagnets; Magnetic flux; BH curves; Magnetic fields; Composite consolidation; Fibrous composites; Fiber-reinforced plastics; Autoclaves; Electromagnetic fields; Clamps (Engineering)

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APA (6^th Edition):

Ziegenbein, J. M. (2011). Magnetic clamping structures for the consolidation of composite laminates. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/43588

Chicago Manual of Style (16^th Edition):

Ziegenbein, Jordan Michael. “Magnetic clamping structures for the consolidation of composite laminates.” 2011. Masters Thesis, Georgia Tech. Accessed March 05, 2021. http://hdl.handle.net/1853/43588.

MLA Handbook (7^th Edition):

Ziegenbein, Jordan Michael. “Magnetic clamping structures for the consolidation of composite laminates.” 2011. Web. 05 Mar 2021.

Vancouver:

Ziegenbein JM. Magnetic clamping structures for the consolidation of composite laminates. [Internet] [Masters thesis]. Georgia Tech; 2011. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/1853/43588.

Council of Science Editors:

Ziegenbein JM. Magnetic clamping structures for the consolidation of composite laminates. [Masters Thesis]. Georgia Tech; 2011. Available from: http://hdl.handle.net/1853/43588

Penn State University

12. Haluza, Rudy T. Mechanical Response of Out-Of-Autoclave Complex Fiber Architecture Composites for Marine Structures.

Degree: 2017, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/14482rth5095

► Hydrokinetic turbines have shown promise as a novel method for harvesting power from natural waterways. The customizability of these turbines allows for smaller turbine systems… (more)

▼ Hydrokinetic turbines have shown promise as a novel method for harvesting power from natural waterways. The customizability of these turbines allows for smaller turbine systems compared to large, geographically demanding hydroelectric plants. However, maintenance costs stemming from relatively short service lives of existing glass/epoxy turbine blades impede the growth of hydrokinetic power. In prototype blades, fatigue loading in salt water caused relatively rapid degradation and subsequent high maintenance costs. Thus, fatigue-resistant blades designed for multi-decade service life would lower the net cost of hydrokinetic turbine usage and increase the feasibility, and therefore growth, of hydrokinetic turbine usage. Furthermore, material systems chosen for hydrokinetic blade use must be studied in order to understand their behavior in long-term under-sea conditions. This study researched the tensile-mechanical response of a quasi-isotropic woven and stitched laminate under quasi-static and fatigue loading at a stress ratio (R) of 0.1 and a frequency of 10 Hz. Some fatigue samples were fatigued until failure, while others underwent residual modulus and strength measurements. Both woven and stitched laminates were found to survive ten million cycles with a maximum stress of +13.75 ksi, but fail prior to ten-million cycles with a maximum stress of +18 ksi. In room-temperature ambient conditions, the polyester-stitched composite proved to have superior fatigue life only in long-life (>105 cycles) fatigue tests. Damaged, but not failed samples showed similar trends in that stitched samples would have more damage at lower cycle counts, but less damage at higher cycle counts compared to woven samples. However, there was more statistical scatter within the stitched specimens compared to woven specimens. Samples that were conditioned and tested while submerged in water had 30% reduction in tensile strength compared to the non-conditioned samples tested in ambient conditions. The partially saturated samples also showed damage accumulation and failure occurring nearly a decade earlier than the non-conditioned samples. Through optical macroscopic and microscopic investigation, intralaminar cracks and delaminations were found to occur in damaged woven samples, while stitched samples showed higher densities of unconnected intralaminar cracks before failure. Delaminations were found in near-failure stitch-bonded samples, especially in those tested at higher maximum fatigue stresses. More intralaminar cracks were found within stitched specimens compared to woven specimens that had similar reductions in elastic modulus, although, stitched specimens showed greater strength retention compared to the woven specimens. Future research could utilize these macroscopic and microscopic crack densities to develop models to better predict turbine blade damage at given loading levels and cycles. Advisors/Committee Members: Kevin L Koudela, Thesis Advisor/Co-Advisor.

Subjects/Keywords: hydro; kinetic; turbine; hydrokinetic; composite; glass; fiber; epoxy; water; marine; fatigue; tension; ooa; out-of-autoclave; damage; fail; condtioning; elevated; temperature; seawater; absorption; model; quasi-laminar; quasi-static; 0.1; tension-tension; sun-li; modulus; residual; strength; reduction; VARTM; woven; weave; stitch; stitch-bonded; textile; wet

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APA (6^th Edition):

Haluza, R. T. (2017). Mechanical Response of Out-Of-Autoclave Complex Fiber Architecture Composites for Marine Structures. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/14482rth5095

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Haluza, Rudy T. “Mechanical Response of Out-Of-Autoclave Complex Fiber Architecture Composites for Marine Structures.” 2017. Thesis, Penn State University. Accessed March 05, 2021. https://submit-etda.libraries.psu.edu/catalog/14482rth5095.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Haluza, Rudy T. “Mechanical Response of Out-Of-Autoclave Complex Fiber Architecture Composites for Marine Structures.” 2017. Web. 05 Mar 2021.

Vancouver:

Haluza RT. Mechanical Response of Out-Of-Autoclave Complex Fiber Architecture Composites for Marine Structures. [Internet] [Thesis]. Penn State University; 2017. [cited 2021 Mar 05]. Available from: https://submit-etda.libraries.psu.edu/catalog/14482rth5095.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Haluza RT. Mechanical Response of Out-Of-Autoclave Complex Fiber Architecture Composites for Marine Structures. [Thesis]. Penn State University; 2017. Available from: https://submit-etda.libraries.psu.edu/catalog/14482rth5095

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Western Ontario

13. Samimi, Rayehe. Enhanced Carbon Fiber-Epoxy Composites for Rowing Racing Shells.

Degree: 2019, University of Western Ontario

URL: https://ir.lib.uwo.ca/etd/6276

► This thesis investigates the thermomechanical properties of two commercial composites using carbon fiber reinforcement in epoxy resins for manufacturing marine based rowing racing shells. The… (more)

Subjects/Keywords: Carbon fiber- epoxy resin; composite prepregs; Vacuum bagging technique (VBO); TGA; DSC; DMA; Instron; Out of Autoclave curing (OoA); Other Chemical Engineering; Other Materials Science and Engineering; Polymer Science; Structural Materials

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APA (6^th Edition):

Samimi, R. (2019). Enhanced Carbon Fiber-Epoxy Composites for Rowing Racing Shells. (Thesis). University of Western Ontario. Retrieved from https://ir.lib.uwo.ca/etd/6276

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Samimi, Rayehe. “Enhanced Carbon Fiber-Epoxy Composites for Rowing Racing Shells.” 2019. Thesis, University of Western Ontario. Accessed March 05, 2021. https://ir.lib.uwo.ca/etd/6276.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Samimi, Rayehe. “Enhanced Carbon Fiber-Epoxy Composites for Rowing Racing Shells.” 2019. Web. 05 Mar 2021.

Vancouver:

Samimi R. Enhanced Carbon Fiber-Epoxy Composites for Rowing Racing Shells. [Internet] [Thesis]. University of Western Ontario; 2019. [cited 2021 Mar 05]. Available from: https://ir.lib.uwo.ca/etd/6276.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Samimi R. Enhanced Carbon Fiber-Epoxy Composites for Rowing Racing Shells. [Thesis]. University of Western Ontario; 2019. Available from: https://ir.lib.uwo.ca/etd/6276

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Missouri University of Science and Technology

14. Anandan, Sudharshan. High temperature polymer composites using out-of-autoclave processing.

Degree: PhD, Mechanical Engineering, Missouri University of Science and Technology

URL: https://scholarsmine.mst.edu/doctoral_dissertations/2758

► "High performance polymer composites possess high strength-to-weight ratio, corrosion resistance, and have design flexibility. Carbon/epoxy composites are commonly used aerospace materials. Bismaleimide based composites are… (more)

Subjects/Keywords: Bismaleimide; Carbon fiber; Composites; FEA; Out-of-autoclave; Materials Science and Engineering; Mechanical Engineering

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APA (6^th Edition):

Anandan, S. (n.d.). High temperature polymer composites using out-of-autoclave processing. (Doctoral Dissertation). Missouri University of Science and Technology. Retrieved from https://scholarsmine.mst.edu/doctoral_dissertations/2758

Note: this citation may be lacking information needed for this citation format:
No year of publication.

Chicago Manual of Style (16^th Edition):

Anandan, Sudharshan. “High temperature polymer composites using out-of-autoclave processing.” Doctoral Dissertation, Missouri University of Science and Technology. Accessed March 05, 2021. https://scholarsmine.mst.edu/doctoral_dissertations/2758.

Note: this citation may be lacking information needed for this citation format:
No year of publication.

MLA Handbook (7^th Edition):

Anandan, Sudharshan. “High temperature polymer composites using out-of-autoclave processing.” Web. 05 Mar 2021.

Note: this citation may be lacking information needed for this citation format:
No year of publication.

Vancouver:

Anandan S. High temperature polymer composites using out-of-autoclave processing. [Internet] [Doctoral dissertation]. Missouri University of Science and Technology; [cited 2021 Mar 05]. Available from: https://scholarsmine.mst.edu/doctoral_dissertations/2758.

Note: this citation may be lacking information needed for this citation format:
No year of publication.

Council of Science Editors:

Anandan S. High temperature polymer composites using out-of-autoclave processing. [Doctoral Dissertation]. Missouri University of Science and Technology; Available from: https://scholarsmine.mst.edu/doctoral_dissertations/2758

Note: this citation may be lacking information needed for this citation format:
No year of publication.

15. Brandley, Mark Wesley. Void Modeling in Resin Infusion.

Degree: MS, 2015, Brigham Young University

URL: https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=6459&context=etd

► Resin infusion of composite parts has continually been reaching to achieve laminate quality equal to, or exceeding, the quality produced with prepreg in an… (more)

▼ Resin infusion of composite parts has continually been reaching to achieve laminate quality equal to, or exceeding, the quality produced with prepreg in an autoclave. In order for this to occur, developers must understand the key process variables that go in to producing a laminate with minimal void content. The purpose of this research is to continue efforts in understanding 1) the effect of process conditions on the resultant void content, with a focus on resin infusion flow rate, 2) applying statistical metrics to the formation, location and size of voids formed, and 3) correlate these metrics with the local mechanical properties of the composite laminate. The variation in dispersion and formation of micro-voids and macro-voids varied greatly between the rates of flow the infusion occurred, especially in the non-crimp carbon fiber samples. Higher flow rates led to lower volumes of micro-voids in the beginning section of the carbon fiber laminates with macro-voids being introduced approximately half-way through infusion. This was determined to have occurred decreasing pressure gradient as the flow front moved away from the inlet. This variation in void content per location on the laminate was more evident in the carbon fiber samples than the fiberglass samples. Micro-voids follow void formation modeling especially when coupled with a pressure threshold model. Macro-void formation was also demonstrated to correlate strongly to void formation models when united with void mobility theories and pressure thresholds. There is a quick decrease in mechanical properties after the first 1-2% of voids signaling strength is mostly sensitive to the first 0-2% void content. A slight decrease in SBS was noticed in fiberglass laminates, A-F as v0 increased but not as drastically as represented in the NCF laminates, G and H. The lower clarity in the exponential trend could be due to the lack of samples with v0 greater than 0% but less than 1%. Strength is not well correlated to void content above 2% and could possibly be related to void morphololgy.

Subjects/Keywords: Mark Brandley; resin transfer molding; void formation; process optimization; out-of-autoclave; carbon fiber; vacuum infusion; resin infusion; Industrial Engineering

…into out-of-autoclave (OoA) technologies. Much of this research has focused on… …laminate as an autoclave at a reduced cost is driving a large amount of research and development… …Resin infusion processes are most often done without the assistance of an autoclave oven, thus… …processing. The effects of voids on composite laminates constructed with autoclave-prepreg… …gap formed between filaments inside a tow, generally smaller than a macro-void Out-of…

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APA (6^th Edition):

Brandley, M. W. (2015). Void Modeling in Resin Infusion. (Masters Thesis). Brigham Young University. Retrieved from https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=6459&context=etd

Chicago Manual of Style (16^th Edition):

Brandley, Mark Wesley. “Void Modeling in Resin Infusion.” 2015. Masters Thesis, Brigham Young University. Accessed March 05, 2021. https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=6459&context=etd.

MLA Handbook (7^th Edition):

Brandley, Mark Wesley. “Void Modeling in Resin Infusion.” 2015. Web. 05 Mar 2021.

Vancouver:

Brandley MW. Void Modeling in Resin Infusion. [Internet] [Masters thesis]. Brigham Young University; 2015. [cited 2021 Mar 05]. Available from: https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=6459&context=etd.

Council of Science Editors:

Brandley MW. Void Modeling in Resin Infusion. [Masters Thesis]. Brigham Young University; 2015. Available from: https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=6459&context=etd

16. Hoagland, David Wayne. Continuous Permeability Measurement During Unidirectional Vacuum Infusion Processing.

Degree: MS, 2017, Brigham Young University

URL: https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=7457&context=etd

► Composite materials have traditionally been used in high-end aerospace parts and low-end consumer parts. The reason for this separation in markets is the wide… (more)

▼ Composite materials have traditionally been used in high-end aerospace parts and low-end consumer parts. The reason for this separation in markets is the wide gap in technology between pre-preg materials processed in an autoclave and chop strand fiberglass blown into an open mold. Liquid composite molding has emerged as a bridge between inexpensive tooling and large, technical parts. Processes such as vacuum infusion have made it possible to utilize complex layups of reinforcement materials in an open mold style set-up, creating optimal conditions for composites to penetrate many new markets with rapid innovation. Flow simulation for liquid composite molding is often performed to assist in process optimization, and requires the permeability of the reinforcement to be characterized. For infusion under a flexible membrane, such as vacuum infusion, or for simulation of a part with non-uniform thickness, one must test the permeability at various levels of compaction. This process is time consuming and often relies on interpolation or extrapolation around a few experimental permeability measurements. To accelerate the process of permeability characterization, a small number of methodologies have been previously presented in the literature, in which the permeability may be tested at multiple fiber volume contents in a single test. Some of the methods even measure the permeability over a continuous range of thicknesses, thus requiring no later interpolation of permeability values. A novel method is presented here for the rapid measurement of permeability over a continuous range of fiber volume content, in a single unidirectional vacuum infusion flow experiment. The thickness gradient across the vacuum bag, as well as the fluid pressure at several locations in the mold, were concurrently measured to calculate the fabric compressibility. An analytical flow model, which accounts for the compressibility, is then used by iterating the fitting constant in a permeability model until the predicted flow front progression matches empirical measurement. The method is demonstrated here for two reinforcement materials: 1) a fiberglass unbalanced weave and 2) a carbon bi-ax non-crimped fabric. The standard deviation of calculated permeabilities across the multiple infusion experiments for each material and flow orientation ranged from 12.8% to 29.7%. Validation of these results was performed by comparing the resulting permeability with multiple non-continuous permeability measurement methods.

Subjects/Keywords: permeability; liquid composite molding; vacuum infusion (VI); fiber volume; compressibility; flow simulation; resin infusion; out-of-autoclave; Industrial Technology

…bonded as opposed to being woven Out-of-Autoclave (OoA)- manufacturing method which… …with a cavity that is the shape of the part being formed, or through the use of an autoclave… …product development of liquid composite molding processes. Definitions and Terms Autoclave- a… …LIST OF FIGURES Figure 1-1: Open Mold Process… …3 Figure 1-3: Autoclave Oven and Mold…

14 more images…

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APA (6^th Edition):

Hoagland, D. W. (2017). Continuous Permeability Measurement During Unidirectional Vacuum Infusion Processing. (Masters Thesis). Brigham Young University. Retrieved from https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=7457&context=etd

Chicago Manual of Style (16^th Edition):

Hoagland, David Wayne. “Continuous Permeability Measurement During Unidirectional Vacuum Infusion Processing.” 2017. Masters Thesis, Brigham Young University. Accessed March 05, 2021. https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=7457&context=etd.

MLA Handbook (7^th Edition):

Hoagland, David Wayne. “Continuous Permeability Measurement During Unidirectional Vacuum Infusion Processing.” 2017. Web. 05 Mar 2021.

Vancouver:

Hoagland DW. Continuous Permeability Measurement During Unidirectional Vacuum Infusion Processing. [Internet] [Masters thesis]. Brigham Young University; 2017. [cited 2021 Mar 05]. Available from: https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=7457&context=etd.

Council of Science Editors:

Hoagland DW. Continuous Permeability Measurement During Unidirectional Vacuum Infusion Processing. [Masters Thesis]. Brigham Young University; 2017. Available from: https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=7457&context=etd

17. Hannibal, Paul. Compressibility Measurement and Modeling to Optimize Flow Simulation of Vacuum Infusion Processing for Composite Materials.

Degree: MS, 2015, Brigham Young University

URL: https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=5432&context=etd

► Out-of-autoclave manufacturing processes for composite materials are increasing in importance for aerospace and automotive industries. Vacuum Infusion processes are leading the push to move… (more)

Subjects/Keywords: Paul Hannibal; vacuum infusion; resin infusion; out-of-autoclave; carbon fiber; fiberglass; compression; compressibility; pressure variance; pressure gradient; simulation; Industrial Engineering

…RTM) is another out-of-autoclave process which uses rigid tooling instead of vacuum… …advances in technology and an increased number of studies of out-ofautoclave manufacturing… …and compressed, the fluid must be forced out of the layup, similar to a sponge releasing… …Vernet 2014). Additionally, if the ratio between the in-plane and out-of-plane flow… …Fiberglass in Epoxy During compression most of the resin contained in the layup is forced out…

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APA (6^th Edition):

Hannibal, P. (2015). Compressibility Measurement and Modeling to Optimize Flow Simulation of Vacuum Infusion Processing for Composite Materials. (Masters Thesis). Brigham Young University. Retrieved from https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=5432&context=etd

Chicago Manual of Style (16^th Edition):

Hannibal, Paul. “Compressibility Measurement and Modeling to Optimize Flow Simulation of Vacuum Infusion Processing for Composite Materials.” 2015. Masters Thesis, Brigham Young University. Accessed March 05, 2021. https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=5432&context=etd.

MLA Handbook (7^th Edition):

Hannibal, Paul. “Compressibility Measurement and Modeling to Optimize Flow Simulation of Vacuum Infusion Processing for Composite Materials.” 2015. Web. 05 Mar 2021.

Vancouver:

Hannibal P. Compressibility Measurement and Modeling to Optimize Flow Simulation of Vacuum Infusion Processing for Composite Materials. [Internet] [Masters thesis]. Brigham Young University; 2015. [cited 2021 Mar 05]. Available from: https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=5432&context=etd.

Council of Science Editors:

Hannibal P. Compressibility Measurement and Modeling to Optimize Flow Simulation of Vacuum Infusion Processing for Composite Materials. [Masters Thesis]. Brigham Young University; 2015. Available from: https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=5432&context=etd

18. Zobell, Brock Don. In Situ Characterization of Voids During Liquid Composite Molding.

Degree: MS, 2017, Brigham Young University

URL: https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=7557&context=etd

► Global competition is pushing the composites industry to advance and become more cost effective. Liquid Composite Molding or LCM is a family of processes that… (more)

▼ Global competition is pushing the composites industry to advance and become more cost effective. Liquid Composite Molding or LCM is a family of processes that has shown significant promise in its potential to reduce process times and cost while maintaining high levels of part quality. However, the majority of research and information on composite processes have been related to prepreg-autoclave processing which is significantly different than LCM. In order for LCM processes to gain large scale implementation, significant research is required in order to model and simulate the unique nature of the resin infusion process. The purpose of this research is to aid in the development of in situ void measurement and characterization during LCM processing, particularly for carbon fiber composites. This will allow for the gathering of important empirical data for the validation of models and simulations that aid in the understanding of void formation and movement during LCM. For such data to be useful, it needs to include details on the formation, mobility and evolution of the void over time during infusion. This was accomplished by creating a methodology that allowed for in situ images of voids to be captured during the infusion process. A clear mold was used to visually monitor infusions during RTM with UV dye and lighting to enhance contrast. Consecutive images were acquired through the use of macro lens photography. This method proved capable of yielding high quality images of a variety of in situ voids during infusions with carbon fiber composites. This is believed to be the first instance where this was accomplished. A second methodology was then developed for the analysis of the collected images. This was done by using ImageJ software to analyze and process the acquired images in order to identify and characterize the voids. Success was found in quantifying the size and circularity of a wide range of micro and macrovoids in both a satin weave and double bias NCF woven fabrics. To facilitate the burden of collecting large amounts of data, this process was made to be automated. A user generated macro script could be applied to large sets of images for rapid processing and analysis. This automated method was then evaluated against manually processed images to determine its overall effectiveness and accuracy as tool for validating void theory.

Subjects/Keywords: Brock Zobell; composites; liquid composite molding; image analysis; void formation; in situ; void measurement; out-of-autoclave; resin infusion; carbon fiber; Industrial Technology

…part geometry, then placed inside of a pressurized oven, called an autoclave, for curing… …equipment costs used in prepreg-autoclave processing. It is also capable of producing parts in a… …fraction of the time, when compared to traditional autoclave processing. Despite its promise, LCM… …to prepreg-autoclave processing. The nature of void formation and optimization techniques… …progress through the infusion process will need to be pulled out of each image. An automated…

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Zobell, B. D. (2017). In Situ Characterization of Voids During Liquid Composite Molding. (Masters Thesis). Brigham Young University. Retrieved from https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=7557&context=etd

Chicago Manual of Style (16^th Edition):

Zobell, Brock Don. “In Situ Characterization of Voids During Liquid Composite Molding.” 2017. Masters Thesis, Brigham Young University. Accessed March 05, 2021. https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=7557&context=etd.

MLA Handbook (7^th Edition):

Zobell, Brock Don. “In Situ Characterization of Voids During Liquid Composite Molding.” 2017. Web. 05 Mar 2021.

Vancouver:

Zobell BD. In Situ Characterization of Voids During Liquid Composite Molding. [Internet] [Masters thesis]. Brigham Young University; 2017. [cited 2021 Mar 05]. Available from: https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=7557&context=etd.

Council of Science Editors:

Zobell BD. In Situ Characterization of Voids During Liquid Composite Molding. [Masters Thesis]. Brigham Young University; 2017. Available from: https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=7557&context=etd

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