Modeling stress upturn at high strain rates for ductile materials

Retired from RAFAEL, Israel

^* Corresponding author : ypartom@netvision.net.il

Published online: 7 September 2018

Abstract

Ductile materials (mainly metals) exhibit a sharp upturn of stress at strain rates around 10³ to 10⁴/s, which is not specific to a certain type of material. It is important to consider stress high rate upturn when dealing with high rate loading, such as shock loading and unloading. Using classical strength models, usually calibrated at not so high rates, may lead to errors with high rate loading and not so high pressures. Here we model high rate upturn on the macroscale. We assume that the upturn mechanism is also responsible for the 4^th power law mechanism put forward by Swegle and Grady. In the past we calibrated our overstress dynamic viscoplasticity model for aluminium from 4^th power law data. Here we use this calibration to predict the high rate stress upturn.