Numerische Bewertung der Schwingfestigkeit geschraubter Blechbauteile

Translated title of the contribution: Numerical evaluation of the fatigue behaviour of bolted thin metal sheets

Robert Pöllinger

Research output: ThesisMaster's Thesis


Due to their easy mounting and releasability, bolted connections are frequently used for connecting components such as batteries, containers, etc. in automotive engineering. A failure of the connection does not always occur in the connecting elements. Especially in the case of thin metal sheets with a thickness of t = 0,8 mm – 1,5 mm, which are frequently used in frame-and-body construction, the crack initiation on edge areas of the bearing surface of bolted connections to the components is a frequent component failure. For the numerical simulation of the body certain guidelines are needed in order to perform a finite element modeling fast and in an automated manner. The finite element mesh, in and around bolted joints, have an important effect. For the investigation, shell models of simple shear and cross tension models were modeled and calculated, according to the modeling of existing guidelines and 3D reference models with very fine discretization. The resulting damage, which was calculated strain based with the fatigue analysis software FEMSITE on the basis of stresses from the FE calculation, has been validated with test results from the literature as well as with simulation results from fine meshed 3D-reference models. By comparing the guidelines, a modelling guideline, that meets the requirements for accuracy and ease of implementation could be found. The damage results of the developed guideline for different sheet thicknesses and materials showed a very good correlation with the shell models of the cross and shear tension specimens with damage results of the linear calculated 3D reference models. Through the numerical investigation of the screw head geometry, using the 3D reference model, the shear tensile tests have shown that the manufacturing tolerance of the screw head has a significant influence on the location of the maximum damage. Furthermore, it was found that, as long as there is friction grip, the influence of the preload is negligible on the damage result. The influence of the linearized contact, in which neighboring element nodes remain closed over the entire calculation, affects the damage result much more. The influence of fretting and heat influence caused by the welding of the nut could be numerically neither refuted nor confirmed by investigations of the 3D reference models. Further tests on components are necessary for the clarification. A mounting frame of an energy storage module with a sheet thickness of t = 1,8 mm and the material DC04 was selected for the verification of the developed guideline. On this frame, a crack after 5,3 hours at the shaker, after a predetermined acceleration-time course with a total running time of 120 hours, emerged. Due to the standard meshing with Abaqus element type S4R elements respectively S4 elements and a nonlinear calculation that has been used for a long time, no failure respectively rather failure could only be predicted in the very late stage of the test run. Through the use of the developed guideline, on this frame, a clear improvement in the prediction of the location and the time of the component failure could be achieved.
Translated title of the contributionNumerical evaluation of the fatigue behaviour of bolted thin metal sheets
Original languageGerman
  • Kepplinger, Gerhard, Supervisor (external), External person
  • Maier, Bernd, Co-Supervisor (internal)
  • Grün, Florian, Supervisor (internal)
Award date20 Oct 2017
Publication statusPublished - 2017

Bibliographical note

embargoed until 13-10-2020


  • numerical evaluation
  • fatigue behaviour
  • thin metal sheets
  • bolted connection
  • finite-element-method

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