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You searched for subject:(mechanical rubbing). Showing records 1 – 3 of 3 total matches.

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Texas A&M University

1. Huang, Zhihao. An Integrated Study of Tribocorrosion in a Duplex Stainless Steel.

Degree: 2015, Texas A&M University

Tribocorrosion is one of the most dangerous threats to material systems due to the accelerated and uncontrollable damage. The interaction of mechanical rubbing and chemical corrosion causes material failure in a quite short time. Tribocorrosion widely exists in different industries, such as mining, oil and gas production, biomedical implants and chemical-mechanical planarization. This thesis studies the tribocorrosion in mild rubbing conditions. A new experimental approach was developed to study the effects of applied loads on passivation and surface defects. Results showed that properties of the passivation layer in duplex stainless steels were affected under different loads and surface defects elongated in the rubbing direction. This new experimental approach was proven to be an effective method to evaluate tribocorrosion in duplex stainless steels in mild wear conditions. Primary experimental approaches were utilized in this study. A new methodology was developed by configuring an integrated triboelectrochemical tester. A flat-on-flat configuration was developed that contained a pair of flat rubbing parts, a tribometer and an electrochemical workstation. A duplex stainless steel 2205 was used due to the wide applications in corrosive environments. The tribocorrosion experiments were conducted in a 3.5wt% NaCl solution. The applied loads ranged from 1N to 3N at a fixed surface speed of 1.5cm/s. Analysis was carried out in evaluating the effects of mechanical rubbing on corrosion and passivation. Results showed that mechanical rubbing promoted corrosion. Meanwhile, a passivation layer was generated due to the interaction of mechanical rubbing and corrosion. When the load was increased, the passivation current density increased first then decreased. The shapes and the sizes of surface defects were affected by different loads. The surface defects elongated in the rubbing direction. Detailed mechanisms were also discussed in this thesis. This thesis includes six sections. After a brief introduction of tribocorrosion, the motivation and objectives of this study are discussed. A new integrated triboelectrochemical approach for studying tribocorrosion is discussed in section 3 along with materials and characterization. Section 4 discusses about the synergy of wear and passivation while the section 5 studies pitting during tribocorrosion. The dissertation ends with conclusion and recommended future work. Advisors/Committee Members: Liang, Hong (advisor), Mukherjee, Partha (committee member), Liu, Li (committee member).

Subjects/Keywords: Tribocorrosion; mechanical rubbing; corrosion; passivation; pitting

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

APA (6th Edition):

Huang, Z. (2015). An Integrated Study of Tribocorrosion in a Duplex Stainless Steel. (Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/156166

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):

Huang, Zhihao. “An Integrated Study of Tribocorrosion in a Duplex Stainless Steel.” 2015. Thesis, Texas A&M University. Accessed September 15, 2019. http://hdl.handle.net/1969.1/156166.

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

MLA Handbook (7th Edition):

Huang, Zhihao. “An Integrated Study of Tribocorrosion in a Duplex Stainless Steel.” 2015. Web. 15 Sep 2019.

Vancouver:

Huang Z. An Integrated Study of Tribocorrosion in a Duplex Stainless Steel. [Internet] [Thesis]. Texas A&M University; 2015. [cited 2019 Sep 15]. Available from: http://hdl.handle.net/1969.1/156166.

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

Council of Science Editors:

Huang Z. An Integrated Study of Tribocorrosion in a Duplex Stainless Steel. [Thesis]. Texas A&M University; 2015. Available from: http://hdl.handle.net/1969.1/156166

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


Indian Institute of Science

2. Subramanya, S. Prediction of Physical Behavior of Rotating Blades under Tip-Rub Impact using Numerical Modeling.

Degree: 2013, Indian Institute of Science

Rotating blades, which are the most critical components of any turbo-machinery, need to be designed to withstand forced vibrations due to accidental tip rub impact against inner surface of casing. These vibrations are typically dependent on operating conditions and geometric parameters. In the current study, a rotor test rig with a maximum tip speed capability of 144 km/hr has been developed for studying the dynamic behavior of representative jet engine compressor blades actuated by the closure of clearance between the tip of a given rotating blade and a sector of the inner lining of the casing. Ten different blade profiles are chosen in the present research. The blades are obtained by lofting NACA GOE123 airfoil cross-section along different stacking axes. Rotor test rigs which simulate transient dynamic events require high frequency data acquisition systems like slip ring arrangement or telemetric transmission. While slip rings introduce noise into the signal, the telemetric transmission works out to be rather expensive. To circumvent the stated shortcomings of data acquisition systems, a novel rotor-mounted data acquisition system has been implemented here which captures dynamic strains in vibrating blades during operation. The current data acquisition system can store data for duration of five seconds with a sampling rate of 35 kHz. It has been calibrated with four standard tests, and provides a simple and efficient mode of data capturing. Three blades with airfoil sections (a flat beam-type blade of uniform rectangular cross-section, a blade with twisted cross-sections stacked along a straight line, and a blade similar to the latter but with a curved stacking axis) are tested under controlled rub conditions at four different speeds. The maximum test speed is restricted to 800 rpm for reasons of safety although the set-up is designed to operate up to a maximum speed of 2000 rpm. For each of the rotor speeds, a blade is tested for three to four different stagger angles in the range of 0o-30o. By plotting the RMS values of measured dynamic responses with respect to stagger angle for a given rotor speed, it has been observed, perhaps for the first time in published literature, that a stagger angle of around 20o yields the maximum RMS value of strain response. A major objective of the current study has been to utilize the data generated in the tip rub impact tests for validating a predictive numerical model of the test set-up using explicit finite element analysis. To this end, a finite element model of the rotor rig inclusive of a rotor with two blades and the static frame structure is developed and analyzed using an explicit LS-DYNA solver. This model is calibrated with the test results of the three blade designs described above. In particular, it has been shown that the frequency contents of the measured dynamic strain responses agree quite well with frequencies obtained from the numerically computed responses. It has been found in the experimental responses that a given blade vibrates with two main… Advisors/Committee Members: Deb, Anindya.

Subjects/Keywords: Turbo Machines - Blades; Rotors - Vibration; Machinery - Vibration; Rotor-Dynamic Test Rig; Airfoil Cross-Section Blades; Rotating Blades; Jet Engine Compressor Blades; Rubbing Impact Load; Aircraft Engine Compressor Blade; Rotating Compressor Blade; Blade Profiles; Rub-Tolerant Blades; Tip-Rub Impact; Rotating Blade; Mechanical Engineering

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

APA (6th Edition):

Subramanya, S. (2013). Prediction of Physical Behavior of Rotating Blades under Tip-Rub Impact using Numerical Modeling. (Thesis). Indian Institute of Science. Retrieved from http://hdl.handle.net/2005/3083

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):

Subramanya, S. “Prediction of Physical Behavior of Rotating Blades under Tip-Rub Impact using Numerical Modeling.” 2013. Thesis, Indian Institute of Science. Accessed September 15, 2019. http://hdl.handle.net/2005/3083.

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

MLA Handbook (7th Edition):

Subramanya, S. “Prediction of Physical Behavior of Rotating Blades under Tip-Rub Impact using Numerical Modeling.” 2013. Web. 15 Sep 2019.

Vancouver:

Subramanya S. Prediction of Physical Behavior of Rotating Blades under Tip-Rub Impact using Numerical Modeling. [Internet] [Thesis]. Indian Institute of Science; 2013. [cited 2019 Sep 15]. Available from: http://hdl.handle.net/2005/3083.

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

Council of Science Editors:

Subramanya S. Prediction of Physical Behavior of Rotating Blades under Tip-Rub Impact using Numerical Modeling. [Thesis]. Indian Institute of Science; 2013. Available from: http://hdl.handle.net/2005/3083

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

3. Hartmann, Lucia. Elaboration et étude de matériaux hybrides orientés et nanostructurés d'intérêt pour l'électronique organique : Elabotation and characterization of oriented and nanostructured hybrid materials of interest for organic electronics.

Degree: Docteur es, Chimie physique, 2012, Université de Strasbourg

Le but de cette thèse était d’élaborer et d’étudier des films minces hybrides orientés et nanostructurés composés d’un polymère semi-conducteur, le poly(3-hexylthiophène) regiorégulier (P3HT) et de nanocristaux semiconducteurs de CdSe (sphères, bâtonnets). Pour cela, deux méthodes ont été mises en œuvre: la croissance épitaxiale directionnelle et le brossage mécanique. Les films de P3HT purs épitaxiés et brossés se différencient en termes de nanomorphologie, d’ordre cristallin et de structure. Les premiers présentent une morphologie lamellaire et une structure de fibre où les chaînes conjuguées sont alignées suivant l’axe de fibre. Les films brossés ne présentent pas de structure lamellaire et les domaines cristallins sont orientés préférentiellement «flat-on». Ces différences se reflètent dans les propriétés optiques des films épitaxiés et brossés. Le degré d’orientation des films brossés dépend fortement du poids moléculaire et une forte anisotropie du transport de charges a été observée. Les films hybrides épitaxiés sont nanostructurés avec localisation des nanocristaux dans les zones amorphes du P3HT. Par ailleurs, l’analyse par tomographie électronique de ces films montre une structure en bicouche avec une couche hybride surmontée d’une couche de P3HT pur. Les films hybrides brossés montrent clairement un alignement des nanobâtonnets de CdSe et des chaînes du P3HT parallèlement à l’axe du brossage. Les degrés d’orientation du P3HT et des nanobâtonnets sont corrélés et dépendent de la proportion en nanoparticules indiquant que c’est la matrice polymère qui induit l’orientation des nanobâtonnets.

The aim of this thesis was to elaborate and characterize hybrid oriented and nanostructured thin films composed of a semiconducting polymer, regioregular poly(3-hexylthiophène) (P3HT) and semiconducting CdSe nanocrystals (spheres, rods). Two orientation methods were used: directional epitaxial crystallization and mechanical rubbing. Epitaxied and rubbedfilms of pure P3HT show strong differences in terms of nanomorphology, crystalline order and structure. Epitaxied films possess a lamellar morphology, a 3D crystalline order and fiber symmetry where the P3HT backbones (cP3HT) are aligned along the fiber axis. Rubbed films do not show a lamellar morphology and have a 2D crystalline order with crystalline domains preferentially oriented “flat-on” relative to the substrate. These differences are reflected in the optical properties of the films. The orientation degree achieved in rubbed films strongly depends on the molecular weight of the polymer. There is also a strong anisotropy of the charge transport properties. Regarding hybrid epitaxied layers, we observed a nanostructuration with a localization of the CdSe nanocrystals into the amorphous zones of the P3HT. Moreover, electron tomography analysis shows that such films have a bilayer structure with a hybrid layer covered by pure P3HT. In rubbed hybrid films prepared with nanorods, the long axis of the nanorods as well as the P3HT backbone are oriented parallel tothe…

Advisors/Committee Members: Brinkmann, Martin (thesis director), Chandezon, Frédéric (thesis director).

Subjects/Keywords: Organique électronique; Polymère semi-conducteur; Poly(3-hexylthiophène); Orientation des polymères; Brossage mécanique; Nanocristaux semiconducteurs; Epitaxie; Ligand; Organic electronics; Semi-conducting polymers; Poly(3-hexylthiophene); Orientation of polymers; Mechanical rubbing; Epitaxy; Ligand exchange; Semi-conducting nanocrystals; 621.38; 668.9

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

APA (6th Edition):

Hartmann, L. (2012). Elaboration et étude de matériaux hybrides orientés et nanostructurés d'intérêt pour l'électronique organique : Elabotation and characterization of oriented and nanostructured hybrid materials of interest for organic electronics. (Doctoral Dissertation). Université de Strasbourg. Retrieved from http://www.theses.fr/2012STRAE028

Chicago Manual of Style (16th Edition):

Hartmann, Lucia. “Elaboration et étude de matériaux hybrides orientés et nanostructurés d'intérêt pour l'électronique organique : Elabotation and characterization of oriented and nanostructured hybrid materials of interest for organic electronics.” 2012. Doctoral Dissertation, Université de Strasbourg. Accessed September 15, 2019. http://www.theses.fr/2012STRAE028.

MLA Handbook (7th Edition):

Hartmann, Lucia. “Elaboration et étude de matériaux hybrides orientés et nanostructurés d'intérêt pour l'électronique organique : Elabotation and characterization of oriented and nanostructured hybrid materials of interest for organic electronics.” 2012. Web. 15 Sep 2019.

Vancouver:

Hartmann L. Elaboration et étude de matériaux hybrides orientés et nanostructurés d'intérêt pour l'électronique organique : Elabotation and characterization of oriented and nanostructured hybrid materials of interest for organic electronics. [Internet] [Doctoral dissertation]. Université de Strasbourg; 2012. [cited 2019 Sep 15]. Available from: http://www.theses.fr/2012STRAE028.

Council of Science Editors:

Hartmann L. Elaboration et étude de matériaux hybrides orientés et nanostructurés d'intérêt pour l'électronique organique : Elabotation and characterization of oriented and nanostructured hybrid materials of interest for organic electronics. [Doctoral Dissertation]. Université de Strasbourg; 2012. Available from: http://www.theses.fr/2012STRAE028

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