Stress investigation on crack tip plastic zone - part II: sub-interface crack and crack in layered materials

• Main Author: Poh, Xuan You.
• Other Authors: Xiao Zhongmin
• Format: Final Year Project
• Language: English
• Published: 2011
• Subjects: DRNTU::Engineering::Materials::Composite materials
• Online Access: http://hdl.handle.net/10356/45980
• Institution: Nanyang Technological University

Elastic-plastic stress analysis has been carried out for the value of J Integral of a sub-interface crack with small scale yielding. In the study, the shape of plastic zone is assumed as a long, slim strip at both crack tips. In the plastic zone, both normal stress and yield stress exist and are considered, due to the bi-material interface. The values of plastic zone size, normal stress and shear stress are pre-determined by satisfying the conditions that both Mode I and Mode II stress intensity factors vanish and the Von Mises yield criterion is met. The value of J Integral is obtained by finding the average value when the loading is fully applied. Lastly, the effect of loading, crack depth (distance to interface), crack length and the thickness of the top layer are being discussed.