How Data Point Numbers in Material Curve Affect Ansys Mechanical Simulation

Finite element analysis (FEA) plays a vital role in new product design. When designing components with a complex geometry and/or complex loading, the nonlinear elastic-plastic analysis method is recommended in the ASME Boiler and Pressure Vessel Code (BPVC). However, the true stress and true strain material curve must be calculated first before elastic-plastic analysis can be performed. ASME BPVC has provided the method to calculate the material curve, but first, the user has to decide how many data points to use in Ansys. Next, the user needs to pick a plasticity model to generate the curve for simulation. This paper describes how Ansys uses the data points in the material curve to calculate the stress and strain, specifically the sublayer or overlay model, in which the material is assumed to be composed of a number of sublayers or subvolumes. In addition, it includes case studies that evaluate the impact of data point numbers in the material curve on the Ansys simulation accuracy and solve time. It was discovered that the simulation accuracy was slightly affected by the data point numbers in the material curve; however, the data point numbers can have a significant effect on the solve time of each iteration: the more data point numbers, the more solve time for each iteration.