A constitutive model for hardness considering the effects of strain, strain rate and temperature

Abstract

The relation between hardness, strain and temperature has been widely investigated over the past decades. However, less attention has been paid to the effect of strain rate on hardness induced in high rate deformations. In this investigation, the relation between strain, temperature and strain rate is studied and a new model is proposed. The investigation is performed by experiment and numerical simulation. The simulations are used to predict the distribution of the strain and strain rate within the specimen. The high rate experiments are conducted using Taylor test, compressive and tensile Hopkinson bar. Quasi-static tests are also carried out using Instron testing machine. The results show a quadratic relation between the hardness and strain rate. The results also indicate that the relation between hardness, strain and temperature is the same for the compressive and tensile loading but the relation between hardness and strain rate is different for the compression and tension. The hardness increases with the increase of the strain and strain rate but decreases with the temperature. The reason is believed to be due to dislocation pile up which is denser in compression than that in tension.

An extensive study on strain dependence of glass fiber-reinforced polymer-based composites

“…Impact loading, however, will lead to responses different from the static state. [21][22][23][24][25] To investigate the effects of strain rate on the behavior of materials in the laboratory, it is necessary to use an appropriate test device 26 capable of adapting and modeling the exact conditions of the event. For this reason, most laboratory studies have been focused on creating real conditions under controlled situations.…”

Determination of constitutive parameters from a Taylor test using inverse analysis

“…With this procedure, they determined the material parameters of constitutive models without the use of stress‐strain curves. Likewise, Majzoobi et al in a later works improved the characterization procedure to use a combined experimental/numerical/optimization technique to determine material parameters for diverse applications and using diverse input data such as inverse Taylor test, compaction tests, and Hopkinson bar tests. Guo et al also proposed a coupled experimental/numerical procedure to identify the Johnson–Cook material parameters at high strain rates of a titanium alloy.…”