A MULTIAXIAL STRESS-STRAIN ANALYSIS FOR PROPORTIONAL CYCLIC LOADING

A simplified treatment is presented for the analysis of tubular specimens subject to in-phase tension-torsion loads in the elasto-plastic regime. Use is made of a hardening function readily obtainable from the uniaxial cyclic stress-strain curve and hysteresis loops. Expressions are given for incremental as well as deformation theories of plasticity. The reversals of loading are modelled by referring the flow equations to the point of reversal.and calculating distances from the point of reversal using a yield criterion. The method has been used to predict the deformation response of in-phase tests on an En15R steel, and comparisons with experimental data are provided. The material exhibited a non-Masing type behaviour. A power law rule is developed for predicting multiaxial cyclic response from uniaxial data by incorporating a hysteretic strain hardening exponent.