Abstract :
The objective of the present work is to clarify ductile fracture phenomena in bulk metal forming, by means of finite-element analyses and experiments. We have developed a computer program, based on a conventional computer program of the finite-element method, with which the behavior of crack growth after ductile fracture can be analyzed. The phenomenon that a material is divided into two materials upon shearing has been simulated by the program, and the following results were obtained. First, in order to perform a precise simulation, we have developed a method of representing the sharp change in the direction of material flow at the tool corners, a method of controlling tool displacement so that an element is fractured in each step and a method of separating nodes at fracture. Second, analytical results of the shape of the sheared surface, the shape of the fractured surface, the length of the sheared surface, the length of the fractured surface and the relationship between the punch displacement and punch force are found to agree with the experimental results. Hence, we have confirmed the validity of the methods.
Keywords :
shearing , Node separation , Severe plastic deformation , Rigid-plastic finite-element method , Ductile fracture , Gurson model
