A Strain Rate Sensitivity Investigation of Aerospace Steel Gear Teeth Via Instrumented Impact Testing
Master of Science
Date of Defense:
Stephen M Copley, Thesis Advisor/Co-Advisor Stephen M Copley, Thesis Advisor/Co-Advisor Surendra B Rao, Thesis Advisor/Co-Advisor
strain rate sensitivity aerospace high hot hardness gear steels instrumented impact testing
The purpose of this research was to investigate the performance of carburized gear teeth made from three aerospace steels at high strain rates and evaluate any potential strain rate sensitivity. Most materials are strain rate sensitive, meaning their strength varies with rate of load application. Instrumented impact testing was performed at five strain rates with carburized gears made from 9310 VIM-VAR, X53 and Vasco X-2M. Load and position data was recorded during the impact event and used for various comparison techniques, including linear deviation point (LDP) strain, peak load, absorbed energy to LDP and absorbed energy to peak load. Metallurgical properties of each material were evaluated and post test fracture analysis was completed. Test results indicate a potential for poor performance at very high strain rates with Vasco X-2M.