Strain Rate Sensitivity Estimation from High Velocity Impact Data.
Abstract
This experimental study was designed to expand on the work accomplished by Sundararajan and Shewmon in estimating the strain rate sensitivity factors for various materials through the use of simple ballistic impact experiments. The study was divided into the following categories: development on an alternate method of estimating average strain rate, expand the existing data to include more relevant aerospace alloys, explore the effects of heat treatment or elevated temperatures on strain rate sensitivity, and to duplicate tests as a verification of assumptions. The experimental procedure involved impacting test specimens with hardened steel spheres of known velocities, the resulting crater depth and diameter could then be correlated to an average strain rate. The energy of impact and crater volume can be equated to an average dynamic flow pressure. The tests results compared favorably with those obtained by Sundararajan and Shewmon, however, their time of impact assumption resulted in errors exceeding 30% for high strain impacts while their crater relaxation profiles as a function of impact velocity was not justified for the materials tested. General observations showed that the materials tested showed a variation in dynamic hardness with increased temperature and increased severity of heat treatment resulted in material less tolerant to strain rate variation. Strain rate sensitivity factors were low for the precipitated hardened alloys, intermediate for the solid solution alloys, and intermediate for the powered metal alloys. Keywords include: Dynamic Plasticity, Hardness, Strain Rate Sensitivity.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1985
- Accession Number
- ADA154703
Entities
People
- M. H. Bednarek
Organizations
- Air Force Institute of Technology