Finite element analysis of thermomechanical manufacturing processes using enhanced graded elements with incompatibility

Finite element analysis (FEA) has become an increasingly popular tool used by researchers and professionals for comparing experimental data to theoretically expected values. While FEA is a powerful tool, it is still prone to inaccuracies if not understood correctly or used properly. The present work concentrates on exploring the various element-based methods available for improving the accuracy of FEA. Specifically, the methods of improvement are made as applied to laser-induced bending for a thin metal sheet through the implementation of graded enhanced finite elements with incompatible modes. The accuracy and efficiency of using enhanced incompatible elements are discussed in three examples. Sequentially coupled thermomechanical analyses have been utilized in the last two examples. The current FE formulation is validated in a practical three-dimensional laser heat process example with test data available. The FEA results have been presented using quantitative measurements of bending angles, vertical displacements, plastic strains and von Mises stress contours. Enhanced incompatible elements provide better computational efficiency compared to higher-order elements and better accuracy compared to low-order elements.