Impact Damage on Various Metal Leading Edges from Small Hard Objects.
Final rept. Mar-Nov 79,
DAYTON UNIV OH RESEARCH INST
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Impact damage on various metal leading edge configurations was studied by performing a series of hard particle impact tests and characterizing the damage. Fatigue tests were used to assess the damage and the concept of an equivalent elastic stress concentration factor was used to characterize severity of damage. Notch fatigue specimens were also fatigue tested in tension to provide baseline data for each material investigated. The materials investigated included 8Al-1Mo-1V titanium, 4130 steel in the annealed and heat-treated conditions, and 7075-T651 aluminum. The data demonstrated good reproducibility and showed that the extent of a particular type of damage could be categorized in terms of an equivalent elastic stress concentration factor. Based on the results, the 4130 steel was superior in performance with the highest critical velocity values and being less sensitive to fatigue degradation than the other materials. No correlation could be established between the critical velocity and the target material parameters of density, modulus, or yield strength. The concept of geometric scaling was investigated by performing a series of tests using different leading edge thickneses and projectile sizes. Observation of the type of damage and plots of critical velocity versus particle size in relation to leading edge thicknesses appeared to validate the scaling concepts. Author
- Metallurgy and Metallography
- Test Facilities, Equipment and Methods