Laser shock peening is a relatively recent technique that introduces compressive residual stresses in metallic structures, improving fatigue, corrosion and wear resistance of treated materials. The purpose of this work is to evaluate numerically the effect of laser shock peening on thin sheets, since most of the numerical analyses available in the literature deal with semi-infinite body assumption, which disregards the reflection of shock waves from the back side of the treated specimen. This phenomenon should be considered when dealing with sheets used for thin walled constructions, for cases in which there is no possibility of using the back-up support, a solid plate in the contact with the backside of the treated sample that limits the wave reflection and deformations. Different set-ups of laser shock peening process are evaluated and an optimal set of parameters is suggested for a possible real structure application.

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The current paper describes a destructive, sectioning method for measuring residual stress in welded panels, using electric strain gauges. Since this method is carried out rather simply, it has a wide range of possible applications. For this reason, a more thorough analysis of the method is performed. The potential limits of its application are investigated, together with the parameters that can influence the obtained results. The sectioning method is verified by determining residual stress in welded panels numerically. The results show it is possible to estimate the residual stress field in a welded structure rapidly and accurately, by using reasonably priced equipment.

PurposeThe aim of this paper is to give a simple and accurate tool for prediction and comparison of residual stresses in laser shock peened and shot peen treated materials.Design/methodology/approachThis work applies finite element code ABAQUS in order to compare the residual stress state and plastic deformation in specimens in aluminium alloy 7050‐T7451, treated with shot peening (SP) and laser shock peening (LSP) processes. Both processes are simulated using the Hugoniot elastic limit (HEL) of the material in question, and the processes are modelled using same input parameters (pressure on the surface of the specimen and the duration of contact between the material and the peening medium).FindingsBy using the same approach in both the analyses, a sound comparison of two technologies can be made, by comparing the obtained residual stress profiles. In addition, surface pressure and contact time can be varied easily in a parametric analysis, allowing the calibration of the numerical results.Research limitations/implicationsOwing to simplicity of used numerical models, different process parameters relative to SP process have not been taken in consideration directly, but through their effect on pressure on the surface of the specimen and the duration of contact between the material and the peening medium.Originality/valueApplication of HEL material model, usually applied to LSP problems, to the analysis of SP process gives promising results, in spite of simplicity of used numerical model.