ONE-DIMENSIONAL NUMERICAL-ANALYSIS OF A BAR SUBJECTED TO LONGITUDINALIMPULSIVE LOADING - USING AN ELASTIC-PLASTIC-VISCOPLASTIC CONSTITUTIVE EQUATION

A tensile elastic-plastic-viscoplastic constitutive equation is propos ed, where the concepts of understress and overstress are introduced. T he strain-rate dependence and the high-strain-rate dependence of stres s are shown using the proposed constitutive equation. An equation is g iven describing propagation speed of an elastic-plastic-viscoplastic s tress wave, and the strain dependence and strain-rate dependence of th is speed. One-dimensional numerical analysis of a bar subjected to lon gitudinal impulsive loading under constant particle velocity loading c onditions is carried out using the proposed constitutive equation. Res ults indicate the attenuation of the constant particle velocity with d istance in the particle velocity-time plane, the existence of the stra in plateau and changing of the plateau with time in the strain-distanc e plane, the existence of constant strain and the attenuation of const ant strain with distance in the strain-time plane, and the maximum val ue of stress at the impact end and its decrement with time in the stre ss-time plane.