Scientific paper ID 2008 : 2020/3

The problem of accelerated fatigue cracks in welds is well known and is one of the reasons for reducing the life of welded metal parts.

The aim of the present study is to analyze the concentrations in an fillet weld formed in the direction of the externally applied force. Common in practice structural variants for joining flat products by overlapping and by additional plates are discussed. The goal is achieved by a virtual experiment to determine the stress in different sections of the weld. In CAD a 3D model of the welded parts is made of structural steel. The parts are welded so as to provide maximum strength of the weld. The model is loaded by static force and by FEA the stress in the dangerous section of the weld is calculated. Solutions were obtained for uniform elastic properties of the parts and the weld. The external load and dimensions of the connected parts are taken into account. No structural changes are taken into account in the area of thermal influence and in the weld.

There is a significant difference between the stress state in the weld, obtained by classical theory and by FEA. The stresses concentrations in the weld were analyzed and it was found that they depend on the construction and stiffness of the welded parts, as well as on the magnitude of the applied external load. The unevenness of the load in the seam is significant and may exceed the recommended values found in the scientific literature. Concentrations in the range 2.9 - 7.9 were obtained. The lower concentration is not always is precondition to a more favorable load and increased service life of the welded parts.