ON TESTING REQUIREMENTS FOR VISCOPLASTIC CONSTITUTIVE PARAMETER-ESTIMATION

Parameter estimation in viscoplastic models using nonlinear least squa res fitting shows potential for reducing testing requirements. An effi cient test matrix must include information to estimate each parameter, but must impose load histories in which the material behavior is domi nated by only a few of the constitutive parameters at any time. Sensit ivity coefficients are derived for each model parameter in MAT-MOD and evaluated for several load histories. Results show the adequacy of th e test matrix performed to provide information for parameter evaluatio n.