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Investigation of Fretting Problem for Frictional Contact on Arbitrary Interfaces Using the Extended Finite Element Method

Moradi, Abbas | 2015

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 47344 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Adib Nazari, Saeed
  7. Abstract:
  8. The problem of fretting fatigue due to the inherent complexity and high probability of its occurrence in many engineering systems, is very important for engineering design. Fretting Fatigue is a significant failure mode in many contacting mechanical components, in which two contact surfaces experience low amplitude oscillatory movement due to cyclic loading. There are many significant contact fatigue problems in structural design which fretting fatigue at lap joints in aging aircraft and fretting fatigue of dovetail joints in gas turbine engine are the most important of them. Numerical simulations provide an appropriate and powerful tool for parametric study of fretting fatigue behavior of materials and crack growth phenomena. The aim of this study is to obtain a general answer to the problem of bodies contacting under fretting fatigue condition with any arbitrary contact surfaces profiles. This research combines three different areas of computational contact mechanics, fracture mechanics and the eXtended Finite Element Method (XFEM). For modeling of frictional contact between two deformable bodies, the mortar formulation and classical law of coulomb are applied. The XFEM due to its capability for modeling crack growth is employed. The use of the XFEM facilitates precise Stress Intensity Factor (SIF) computations on comparatively coarse meshes, and additionally, no remeshing is required for crack growth simulations. The updated Lagrangian formulation is used to model the inherent nonlinearity of contact and geometrical nonlinearity of the problem. The resulting nonlinear equilibrium equations are solved by the Newton–Raphson method in an iterative procedure. The model predicts number of cycle to crack initiation, and also location and orientation of crack initiation. SIF histories are provided using discrete crack growth simulations and are contributed into the crack growth model to compute propagation cycles. The sum of fretting nucleation plus propagation cycles is the total life. Several examples are solved and compared with experimental results of other investigators, was to assess the accuracy of the algorithms.
    Using the tools presented in this study, several practical problems in fretting fatigue field, without imposing restrictive assumptions can be solved and fretting fatigue crack initiation and propagation lives can be obtained
  9. Keywords:
  10. Fretting Fatigue ; Life Time Estmation ; Frictional Contact ; Extended Finite Element Method ; Mortar Algorithm

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