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You searched for subject:(Strength AND Condtioning). Showing records 1 – 2 of 2 total matches.

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Penn State University

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

Degree: 2017, Penn State University

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

APA (6th 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 (16th Edition):

Haluza, Rudy T. “Mechanical Response of Out-Of-Autoclave Complex Fiber Architecture Composites for Marine Structures.” 2017. Thesis, Penn State University. Accessed April 16, 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 (7th Edition):

Haluza, Rudy T. “Mechanical Response of Out-Of-Autoclave Complex Fiber Architecture Composites for Marine Structures.” 2017. Web. 16 Apr 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 Apr 16]. 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


AUT University

2. Tinwala, Farhan Akbari. Horizontal Eccentric Towing and Its Effects on Sprint Performance .

Degree: AUT University

The success of many team sports and track and field athletes can be in part linked with their sprint performance. Therefore, improving sprint performance has been the foci of researchers and practitioners alike. The most commonly used tools that deliver sprint-specific training stimuli are resisted towing devices (RST) (e.g. sleds). RST provides a predominantly concentric (CON) horizontal overload to the musculo-skeletal system, especially in the acceleration phase of the sprint. Perhaps an eccentric (ECC) horizontal overload may be beneficial given the benefits of ECC training; such as, injury prevention and rehabilitation, shift towards faster muscle phenotypes, hypertrophy, strength and power improvements. This resulted in the overarching research question, “Can a novel horizontal ECC towing device improve sprint performance?”. The aim of this thesis was to develop a device that would provide a horizontal ECC stimulus, evaluate the biomechanics of the device and test its effects on sprint performance. A review of existing ECC training devices found limited devices overload in the horizontal plane and none eccentrically overload the musculo-skeletal system in a sprint-specific gait. Therefore, a movement termed horizontal ECC towing (HET) was developed which involves an athlete in a sprint stance trying to move forwards but is being pulled backwards. A device termed the HET device was then developed to automate this movement. The device was powered by a 10 kW electric motor that can tow athletes at velocities up to 3.58 m/s and can tolerate forces up to 2.8 kN. Two familiarisation sessions were found to achieve movement consistency during HET. Biomechanics analysis was conducted to further understand the movement which would help inform training programme development for coaches. Since HET is a novel movement, no research existed. Thus, ECC towing was compared to its opposite, the CON towing direction (CTD). Statistical Parametric Mapping (SPM) analysis of ground reaction force (GRF) profiles found that the two directions were significantly different (p<0.05) and were applying different movement strategies to produce force. This suggested that different lower limb joints were likely responsible for CON and ECC force production. Vertical and horizontal GRFs were lower in the ECC direction (p<0.05), which may be limited by the coefficient of friction and indicated that isokinetic horizontal towing does not follow the contractile-force-velocity relationship. Power and work analysis of the lower limb joints showed that the ankle and hip joints are absorbing energy and likely dissipating it in the ECC towing direction (ETD). ETD has greater ankle and hip joint power absorption and much smaller power production. A four-week intervention of ECC and CON towing in elite female field hockey players (n=10) resulted in no improvements in split times. There is still an opportunity for practitioners and researchers to apply a unique ECC stimulus to their athletes. The intervention study had its limitations as it was based out of… Advisors/Committee Members: Cronin, John (advisor), Haemmerle, Enrico (advisor), Ross, Angus (advisor).

Subjects/Keywords: Strength and Condtioning; Biomechanics; Industrial Automation; Resistance Training; Elite Athlete Performance; Design and Development

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

APA (6th Edition):

Tinwala, F. A. (n.d.). Horizontal Eccentric Towing and Its Effects on Sprint Performance . (Thesis). AUT University. Retrieved from http://hdl.handle.net/10292/13448

Note: this citation may be lacking information needed for this citation format:
No year of publication.
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Tinwala, Farhan Akbari. “Horizontal Eccentric Towing and Its Effects on Sprint Performance .” Thesis, AUT University. Accessed April 16, 2021. http://hdl.handle.net/10292/13448.

Note: this citation may be lacking information needed for this citation format:
No year of publication.
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Tinwala, Farhan Akbari. “Horizontal Eccentric Towing and Its Effects on Sprint Performance .” Web. 16 Apr 2021.

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

Vancouver:

Tinwala FA. Horizontal Eccentric Towing and Its Effects on Sprint Performance . [Internet] [Thesis]. AUT University; [cited 2021 Apr 16]. Available from: http://hdl.handle.net/10292/13448.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
No year of publication.

Council of Science Editors:

Tinwala FA. Horizontal Eccentric Towing and Its Effects on Sprint Performance . [Thesis]. AUT University; Available from: http://hdl.handle.net/10292/13448

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
No year of publication.

.