Title

Verification and calibration of state-of-the-art CMC mechanistic damage model

Date of Award

2016

Degree Name

M.S. in Mechanical Engineering

Department

Department of Mechanical and Aerospace Engineering

Advisor/Chair

Advisor: Margaret Frances Pinnell

Abstract

Due to their low density, high toughness and elevated temperature performance, Ceramic Matrix Composites (CMCs) are attractive candidates for replacing metals in many high temperature applications, such as gas turbine engines and exhaust nozzles. While there are numerous benefits to CMCs, there are several limitations hindering the full-scale application within the aerospace industry. One significant limitation is the ability to accurately model and predict CMC damage behavior. A mechanistic approach to modeling the damage behavior in CMCs was previously developed by Structural Analytics. The damage model, CLIP (Ceramic Matrix Composite Life Prediction), is embedded in a software package that consists of an ABAQUS user-subroutine, as well as a standalone application. The current study verifies the model by calibrating it to a slurry melt-infiltrated SiC/SiC composite. A series of experimental tests were conducted at the Air Force Research Laboratory (AFRL) including montonic tensile tests at 23°C, 800°C and 1200°C, a creep test at 1200°C and a sequentially loaded tensile test at 23°C. The results from the experimental tests were used to calibrate the damage model. The calibration was concluded as successful when the model could produce matching stress-strain curves to the experimental data at the respective temperatures. Finally, the model was used to make predictions for intermediate temperature ranges of monotonic tension, sequentially loaded tension, and off-axis tension.

Keywords

Ceramic-matrix composites Effect of heat on, Ceramic-matrix composites Stress corrosion, Mechanical Engineering, Materials Science, ceramic matrix composite, ABAQUS, CLIP, damage model, calibration, SiC-SiC, material characterization

Rights Statement

Copyright 2016, author

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