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Numerical Modeling and Optimization of Cold and Hot Powder Forming Processes

keshavarz hadad , Shahriyar | 2008

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 40329 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Khoei, Amir Reza; Khalo, Ali Reza
  7. Abstract:
  8. In this thesis, a shape optimization technique is presented for powder forming processes based on the genetic algorithm approach. The numerical modeling of powder compaction simulation is applied based on a large deformation formulation, powder plasticity behavior, and frictional contact algorithm. A Lagrangian finite element formulation is employed for large powder deformations. A cap plasticity model is used in numerical simulation of nonlinear powder behavior. The influence of powder-tool friction is simulated by the use of penalty approach in which a plasticity theory of friction is incorporated to model sliding resistance at the powder-tool interface. For hot compaction process coupled thermo mechanical problem of Hot lsostatic Pressing (HIPing) of metal powders during densification process is analyzed using analytical as well as numerical techniques. Densification of the powder is assumed to occur due to plastic yielding of the metal particles as well as due to boundary and surface diffusion. The constitutive models developed are used to describe the inelastic behavior of the metal powder. A modified cap plasticity model with temperature effect is used in numerical simulation of nonlinear powder behavior.

  9. Keywords:
  10. Optimization ; Genetic Algorithm ; Friction ; Large Deformation ; Cold and Hot Compaction Process ; Cap Plasticity Model

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