Stabilität von Eigenspannungen kugelgestrahlter Pleuel unter zyklischer Beanspruchung

Translated title of the contribution: Residual stress stability of shot peened conrods under cyclic loading

Lukas Liebfahrt

Research output: ThesisMaster's Thesis


In order to counteract the increasing global climate change, authorities define directives to regulate the emission of air pollutants and the fleet consumption. The responsibility for the realisation of these guidelines lies with the vehicle manufacturers, who use different strategies to meet the legal requirements. Apart from the application of alternative propulsion systems, the reduction of the vehicle weight is of significant importance. Safety requirements and the tendency to enhance powers in the automotive industry constitute a conflict of interest. This results in the persistent trend of applying lightweight design technologies in automotive engineering, where primarily material lightweight construction is a commonly applied principle. The shot peening process offers a comparatively cost-effective method to increase material strength. This surface procedure treats the components with blasting abrasives that, due to plastic deformation, hardens the material and induce compressive residual stresses. Specifically distinct conditions of compressive residual stresses close within the surface layer enhance the local fatigue strength. Therefore, the stability of the residual stress state is of utmost importance to evaluate the durability of lightweight components. This master thesis focuses on a simulation method that determines the residual stress by the shot peening process and aims to transfer it on a real component, which is in this case a conrod from an internal combustion engine. To identify the material properties, tensile, low cycle fatigue and creep tests were performed on specimen, which were manufactured from the conrods. These evaluated material parameters were used to undertake a shot peening simulation, and the numerically computed residual stress as well as the hardening values were transferred onto the conrod geometry. In order to investigate the stability of residual stresses, a periodic load simulation of the whole conrod model was executed. The numerical results show a significant reduction of residual stresses in the first cycles. Experiments with identical load cases were performed on the shot peened conrod to enable an accurate validation of the simulation results. Residual stresses were radiographically measured at different load cycles on surface and in depth. The measurement results before loading and after one load cycle correlate well with the results from the simulation with a mean deviation of 14 %. Therefore, the discussed method is suitable to estimate the cyclic stability of residual compressive stresses, which are induced into the surface layer by the shot peening process.
Translated title of the contributionResidual stress stability of shot peened conrods under cyclic loading
Original languageGerman
Awarding Institution
  • Montanuniversität
  • Leitner, Martin, Co-Supervisor (internal)
  • Grün, Florian, Supervisor (internal)
Award date15 Dec 2017
Publication statusPublished - 2017

Bibliographical note

embargoed until 01-12-2021


  • Residual stresses
  • residual stress relaxation
  • simulation
  • residual stress stability

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