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Post-treatment techniques like the high frequency mechanical impact treatment (HFMI) exhibit a significant fatigue life enhancement of welded joints. The effectiveness of this mechanical impact treatment is primarily based on the combination of three effects: the local hardness increase, compressive residual stresses and reduced notch stress concentration at the weld toe. The goal of the present study was to develop a computationally efficient approach for predicting residual stresses induced by the HFMI process on steel specimens. For that purpose, explicit simulations of this post weld treatment technique were performed utilizing the software package ABAQUS. Although, the focus of this study is to find suitable process and material parameters as input for the numerical simulation. For this, the impact velocity, contact force and permanent indentation depth of a pneumatic HFMI-tool were measured

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The objective of the present study is a numerical analysis of disorder effects in solid structural foams caused by their random irregular micro structure. Using a strain energy based concept. the effective material response is computed in a geometrically non-linear homogenization analysis. The probabilistic homogenization is based on the analysis of a large scale statistically representative volume element. The stochastic information about the scatter in the material response on the lowest possible level is generated by a subsequent division of the representative volume element in substructures consisting of a single cell wall intersection and parts of the adjacent cell walls. For each of the substructures, a homogenization analysis is performed. The results for the local effective stress and strain components are evaluated by means of stochastic methods. The approach is illustrated by a number of examplary studies on the uncertainty of the effective material response of two-dimensional model foams with linear and non-linear elastic material behavior on the cell wall level of structural hierarchy