The influence of the work hardening rate on ductile fracture

✍ Scribed by A. Melander

• Publisher: Elsevier Science
• Year: 1980
• Weight: 542 KB
• Volume: 28
• Category: Article
• ISSN: 0001-6160
• DOI: 10.1016/0001-6160(80)90033-4

✦ Synopsis

A fracture criterion is formulated which states that strain localization occurs if the energy to deform the material by unit strain starts to decrease. The model takes into account the work hardening rate of the matrix and the softening effect due to void growth.

A model for void growth during tensile testing is used which assumes that the voids elongate at the same rate as the material in general. This growth model describes experimental results on copper wire very satisfactorily. The Bridgeman technique has been used to study the hydrostatic pressure in the neck of copper wire during tensile testing. The hydrostatic pressure is found to decrease linearly with strain in the neck. The void growth model and the linear description of the hydrostatic pressure with strain are used in the fracture model. The fracture criterion then predicts how the fracture strain depends on the volume fraction of particles and on the strain hardening parameter of the material. The results of the fracture criterion are compared to experimental results on copper in a hot rolled and a cold drawn condition. The two conditions of the material have similar particle and void structures before tensile testing but have different strain hardening characteristics. The model can describe the influence of the work hardening rate on the fracture strain of the two conditions of copper.