Efficient finite element modelling and simulation of welding

Abstract: This thesis presents development of methods, methodologies and tools for efficient finite element modelling and simulation of welding. A novel 8- to 16-noded solid shell element has been developed. It uses only displacement degrees of freedom, thus it can easily be connected with a regular brick element. The element has proven to perform well in standard tests for shell as well as in geometrical and material non-linear problems. An error based adaptive remeshing scheme has been developed. It is found that the combination of the two error measures, based on the heat flux and the effective stress, is predicting an accurate mesh for a plate and a pipe welding case. To improve the efficiency of material addition in multipass welding two different strategies was compared. These two strategies, named quiet and inactive element, were used in a simulation of a very thick plate. Results showed that the inactive element strategy was preferable in terms of numerical efficiency. A generic process methodology is used to identify and develop critical activities in the modelling and simulation of welding. The methodology is used to compare simulation results of elementary case studies to results of more refined analysis. The elementary case studies is suggested to support decision making in the early design phase of product development.