The evolutionary optimization of selected welded structures

Purpose: of this paper is to present the recent possibility of evolutionary optimization method application to predicting the proper welding parameters in the weld process. The objective of the welding simulation is to study the temperature generated during the welding process and to investigate residual stresses in the component after the welding. Such results give the possibility to determine stress and strain state of welded parts and properties of materials in welding zones. From other side it gives the possibility to perform optimization process looking for welding parameters (welding speed, welding power source etc.) or initial shape of welded sheets according to displacement state (welding of thin metal sheets with stiffeners – T joints). Those results are the base for fatigue analysis too. Design/methodology/approach: In the paper the foundations of FEM simulation of welding process are presented. Also a grid based evolutionary optimization of welding parameters influences on strength parameters in the heat affected zone (HAZ) is shown. Numerical simulation of a welding process using the finite element method is applied. Findings: Results for coupled thermo-mechanical problem are prescribed. Two examples, the grid based evolutionary optimization of HAZ parameters and grid based evolutionary optimization of T-joint component deformation, illustrate the possibility of computational simulation and optimization of welding are presented. Practical implications: Computational simulation and evolutionary optimization give a lot of information very important for engineers. An undesirable side-effect of welding is the generation of residual stresses and deformations in the component and the quality of the weld has a substantial impact on the fatigue life of the structure. These resultant deformations may render the component unsuitable for further use. Originality/value: The presented the grid based evolutionary optimization procedure is a new tool for better understanding and predicting the welding behaviour from the thermo-mechanical process point of view. It gives the possibilities to optimize main welding parameters in order to achieve better structures, taking into account nearly full set of welding parameters, temperature dependent material parameters and simulating the coupled thermo-mechanical problem.