Loading...

Powder Compaction Simulation of Nonlinear Behavior of Material with Peridynamics Theory

Sepahvand, Hossein | 2020

498 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 53425 (09)
  4. University: Sharif University of Technology
  5. Department: Machanical Engineering
  6. Advisor(s): Khoei, Amir Reza
  7. Abstract:
  8. The present research focuses on the simulation of the metallic powder compaction process with the Peridynamics theory. Various methods are exploited to simulate this process in literature. Studying the nonlinear behavior of powders includes different phenomena such as dislocation and grain boundary, making it complicated. However, numerous research has been shaped to consider these phenomena on the micro-scale. There is also another batch of nano-scale studies underway. In this class of simulations, considering atoms as rigid particles, interatomic potentials, and molecular dynamics methods are used. Because of atomic-scale precision, this approach has very high accuracy. The massive computational cost caused researchers to use it in modeling nano-scale problems and not in industrial and daily engineering simulations such as mechanical components forming. Multiscale methods are another approach that can be used in higher scale simulations. This approach is based on transferring data interscale. To increase accuracy in this approach, we must consider a large enough RVE that led to high computational cost, which violates our concerns. On the other hand, flourishing Peridynamic theory in the computational mechanics' community in recent years made us go for it regarding this purpose. This method is categorized as a subset of nonlocal continuum theories that use displacement field derivatives rather than the displacement field to compute stresses. Due to not using this method in cold powder compaction studies, we decided to use it for the first time. In this theory, the buddy is assumed as arranged discrete particles in the space that each particle has a pair-wise force interaction with all other particles in its neighborhood. Regarding the complex geometry of the compaction process and nonlinear behavior of powders, which depends on its relative density, two approaches were adopted. In the former approach, a constitutive law that is a function of relative density is chosen. The whole powders are then considered a continuous porous medium, and relative density affects the medium as an internal variable in the constitutive relations. Due to modeling powders as discrete particles, relative density changed according to void space between powder particles in the latter approach. In this approach, powder particles are assumed as dens buddies, and contact forces handle force interactions between buddies. In the end, several numerical examples are provided to demonstrate the ability of the method
  9. Keywords:
  10. Forming ; Compression ; Metal Powder ; Finite Element Analysis ; Plasticity ; Nonlinear Behavior ; Continuum Mechanics ; Multi-Scale Simulation ; Cone-Cap Plasticity Model ; Peridynamics ; Particle-Based Method

 Digital Object List

 Bookmark

No TOC