A Study of Two Alternate Tangent Modulus Formulations and Attendant Implicit a L G O R I T H M S for Creep as Well as High-strain-rate Plasticity*

Abstract-Two alternate tangent modulus formulations based on the use of material characteristics expressed as ~vp = g(i~.p,#) and 8 = h(i°P,~P), respectively, are presented for the analysis of material response under conditions such as high temperature creep and high strainrate dynamic plasticity. In each formulation, implicit algorithms of generalized midpoint radial mapping are presented to compute stress histories at a material point. Several examples to illustrate the stability, accuracy, and convergence of the presented computational methodologies are included. In each instance, the two alternate tangent modulus approaches lead to results of comparable accuracy and compare excellently with each other as well as other available independent solutions.