2.06 - Material Behavior at a Wide Range of Strain Rates

Abstract

This article presents the most common tests used to infer the mechanical response of materials (i.e., the material stress–strain curve). Different techniques are discussed, leading to measurement of the materials response in a wide range of strain rates, from quasistatic to very fast loading. The article begins with an appraisal of the importance of knowing the material strength. Basic concepts of strain and stress measures are introduced. Next, follows a detailed description of the tensile and compressive tests, side by side with the techniques used to measure the strains. Midrange-strain-rate devices are presented next, allowing one to obtain the material response necessary in various daily applications. High-strain-rate tests are then discussed next, with the detailed presentation of the main mechanical device used in these tests: the split Hopkinson pressure bar. Both compressive and tensile test devices are presented, as well as the basic equations used for data interpretation. Next follows a short section on constitutive laws, with the article finishing with a discussion on the various methods used, including indentation tests. The mechanical behavior of various materials is presented within the sections.