Practical Constitutive Models Covering Wide Ranges of Strain Rates, Strains and Temperature

摘要

To analyze numerically the dynamic behavior of materials and/or structures under impact loading using computer codes, practical constitutive models covering a wide range of strain rates, a large strain region and a wide range of temperature are important. In this paper, new experimental results of strain rate dependency of strength for several materials are reported. By examining these recent experimental data and many other experimental results obtained by us and many other researchers, it was confirmed that specific relationships between the strain rate sensitivity and the static strength of materials existed for each individual material group such as group of iron and steels, group of aluminum and its alloys, group of copper and its alloys, and group of titanium and its alloys. Incorporating these relationships into the newly modified constitutive model first proposed by Tanimura (1992), simulations of the dynamic material properties were carried out and showed a good agreement with experimental results in wide ranges of strain rates, strains, and temperature. It should be stressed that by using this newly modified constitutive model and unified sets of values of parameters specified for each material group, one can simulate stress-strain curves in the wide ranges of strain rates of 10~(-4) approx 10~5s~(-1) and of temperature as long as the quasistatic stress-strain curve of the material at room temperature (at a reference strain rate and a reference temperature) is known in advance.