Load identification for viscoplastic materials with some unknown material parameters

To inversely identify the loads applied on structure, sufficient information about the material properties is usually required. In this paper, an innovative and robust inverse approach is proposed for the load identification of a viscoplastic material with some unknown viscoplastic constants, where both of the unknown constants and the applied load are simultaneously identified using two nested inverse algorithms. In this work, the well-known damped Gauss–Newton method is used for the load identification and the Marquardt–Levenberg method for identifying the unknown material parameters. Suitable regularization techniques are also used to obtain more smooth solutions. The Perzyna model is used for description of the viscoplastic behavior. A meshfree method is used for the direct and sensitivity analysis of the viscoplastic problem. In order to show the effectiveness of the proposed method, two different examples are presented. Also, influences of the effective parameters, such as the number and location of sampling points, on the results are investigated too.