Measurement of Material Properties for High Rate Deformation Processes.
Interim rept. 1 Jun-1 Nov 81,
AIR FORCE WRIGHT AERONAUTICAL LABS WRIGHT-PATTERSON AFB OH
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As higher and higher strain rates are achieved in experiments, the deformation field varies from one which is nearly homogeneous to the case where high amplitude stress waves or shock waves are propagating. In order to analyze a high rate experiment, a sound mathematical theory of wave propagation is required. This, in turn, requires a description of the material behavior. But it is this description of material behavior which is being sought in the first place. It is this dilemma which has caused problems in deducing the dynamic properties of materials at very high strain rates. Techniques available for determining the high rate properties of materials are reviewed. These range from split Hopkinson bar, in which a uniaxial stress state is assumed, to the flat plate impact experiment where waves of uniaxial strain occur. Other configurations include expanding rings and cylinders and skew plate impacts. These various techniques are discussed with respect to their fundamental limitations and the type of material property data which can be obtained. Author
- Metallurgy and Metallography