자료유형  

 학위논문

Control Number  

0017161523

International Standard Book Number  

9798342104746

Dewey Decimal Classification Number  

300

Main Entry-Personal Name  

Sharma, Akshat.

Publication, Distribution, etc. (Imprint  

[S.l.] : Purdue University., 2024

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2024

Physical Description  

172 p.

General Note  

Source: Dissertations Abstracts International, Volume: 86-04, Section: B.

General Note  

Advisor: Sadeghi, Farshid.

Dissertation Note  

Thesis (Ph.D.)--Purdue University, 2024.

Summary, Etc.  

요약Fretting wear occurs when two contacting bodies under load are subjected to small amplitude oscillatory motion. Depending on the applied normal load, displacement amplitude, coefficient of friction and resulting shear force, two types of fretting wear regimes exist - (i) partial slip and (ii) gross slip. At displacement amplitudes higher than gross slip condition, sliding wear regime prevails. Fretting wear becomes dominant in machine components subject to vibrations such as bearings, dovetail joints, etc. whereas sliding wear is observed in brakes, piston-ring applications, etc. The work in this dissertation primarily focuses on characterizing the material response of various machine components subjected to fretting and sliding wear regimes.At first, the friction and fretting wear behavior of inlet ring and spring clip components used in land-based gas turbines was investigated at elevated (500°C) temperature. In order to achieve this objective, a novel high-temperature fretting wear apparatus was designed and developed to simulate the conditions existing in a gas turbine. The test apparatus was used to investigate fretting wear of atmospheric plasma sprayed (APS) Cr3C2-NiCr (25% wt.), high-velocity oxy-fuel (HVOF) sprayed Cr3C2-NiCr (25% wt.), HVOF sprayed T-800 and APS sprayed PS400coated inlet rings against HVOF-sprayed Cr3C2-NiCr (25% wt.) coated spring clip. The PS400 coated inlet rings demonstrated a significant reduction in friction and wear. A finite element (FE) framework was also developed to simulate fretting wear in HVOF-sprayed Cr3C2-NiCr composite cermet coating. The material microstructure was modelled using Voronoi tessellations with a log-normal distribution of grain size. Moreover, the individual material phases in the coating were randomly assigned to resemble the microstructure from an actual SEM micrograph. A damage mechanics based cohesive zone model with grain deletion algorithm was used to simulate debonding of the ceramic carbide phase from the matrix and resulting degradation from repeated fretting cycles. The specific wear rate obtained from the model for the existing material microstructure was benchmarked against experiments. Novel material microstructures were also modeled and demonstrated to show less scatter in wear rate.Following, a three-dimensional (3D) continuum damage mechanics (CDM) FE model was developed to investigate the effects of fretting wear on rolling contact fatigue (RCF) of bearing steels. In order to determine the fretting scar geometry, a 3D arbitrary Lagrangian-Eulerian (ALE) adaptive mesh (AM) FE model was developed to simulate fretting wear between two elastic bodies for different initially pristine fretting pressures (0.5, 0.75 and 1 GPa) and friction coefficients (0.15, 0.175 and 0.25) resulting in stick zone to contact width ratios, c/a = 0.35, 0.55 and 0.75. The resulting wear profiles were subjected to various initially pristine RCF pressures (1, 2.2 and 3.4 GPa). The pressure profiles for RCF were determined by moving the contact over the fretted wear profiles in 21 steps. These pressure profiles were then used in the CDM-FE model to predict the RCF life of fretted surfaces. The results indicate that increased fretting pressure leads to more wear on the surface, thereby reducing RCF life. As the RCF pressure increases (PRCF≥ 2.2 GPa), the effect of fretting on RCF life decreases for all fretting pressures and c/a values, indicating that life is primarily governed by the RCF pressure.

Subject Added Entry-Topical Term  

Load.

Subject Added Entry-Topical Term  

Humidity.

Subject Added Entry-Topical Term  

Bearings.

Subject Added Entry-Topical Term  

Grain boundaries.

Subject Added Entry-Topical Term  

Normal distribution.

Subject Added Entry-Topical Term  

Crack initiation.

Subject Added Entry-Topical Term  

Wear tests.

Subject Added Entry-Topical Term  

Adhesive wear.

Subject Added Entry-Topical Term  

Energy.

Subject Added Entry-Topical Term  

Grain size.

Subject Added Entry-Topical Term  

Microstructure.

Subject Added Entry-Topical Term  

Mechanics.

Subject Added Entry-Topical Term  

Boundary conditions.

Subject Added Entry-Topical Term  

Nitrogen.

Subject Added Entry-Topical Term  

Corrosion.

Subject Added Entry-Topical Term  

Friction.

Subject Added Entry-Topical Term  

Carbon.

Subject Added Entry-Topical Term  

Wear resistance.

Subject Added Entry-Topical Term  

Chemical vapor deposition.

Subject Added Entry-Topical Term  

Lubricants & lubrication.

Subject Added Entry-Topical Term  

Industrial engineering.

Subject Added Entry-Topical Term  

Materials science.

Subject Added Entry-Topical Term  

Mathematics.

Added Entry-Corporate Name  

Purdue University.

Host Item Entry  

Dissertations Abstracts International. 86-04B.

Electronic Location and Access  

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Control Number  

joongbu:657707