Evaluation of the numerical stability and sensitivity of material parameter variations for several unified constitutive models

摘要

The sensitivity of unified constitutive theories to numerical integration techniques was investigated. Numerical simulations of Hastelloy-X at 1800 F were evaluated in uniaxial form. Both single and multistep integration schemes were used. The various algorithms were compared with regard to accuracy, stability, and computational economy. The material parameter sensitivity was studied by varying the material constants by a specified amount and comparing predicted responses. Numerical comparisons show that, of the numerical integration methods studied, Eulers method is the most accurate, stable, and efficient procedure. The input sensitivity studies indicated that some constitutive models are more sensitive to experimental errors than others and that a 5% error in certain material constraints may lead to 15 to 30% changes in predicted response.