Fracture mechanics investigation on interface crack kinking

• Main Author: Toh, Benjamin Choon How
• Other Authors: Xiao Zhongmin
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Mechanical engineering::Mechanics and dynamics
• Online Access: http://hdl.handle.net/10356/61317
• Institution: Nanyang Technological University

The aim of this project is to study the effect of dissimilar materials with different elastic properties on the stress state around an interface crack in an infinite composite plate subject to tension. A simulation ran by the ABAQUS/Standard 6.10 software is used to model and analyse this phenomenon. The simulation was carried out in three phases. The first phase involved modelling a crack at the interface of a two-dimensional linear elastic composite material. The modelling includes setting up the parameters of the elastic properties as well as the loading and boundary conditions of the model. By varying the Young’s Modulus of the two dissimilar plates, the different Stress Intensity Factors values were obtained from the simulation. The second phase also involved modelling a crack at the interface of a two-dimensional linear elastic composite material. However in this case, XFEM crack growth method is utilized in order to model a crack kink. By varying the Young’s Modulus of the two dissimilar plates, the different Kink Angles were obtained from the simulation. The third phase involved observing the effect of coating-substrate composite on the Stress Intensity Factor and Kink Angle values. This is accomplished by investigating crack propagation of a crack at the interface between two semi-infinite dissimilar materials. From the results, we observe that as the linear elastic material properties of the two plates become more similar, the Stress Intensity Factor ratios converge to unity and the Kink Angle gradually decreases to zero. In addition, the effect of coating-substrate composite is not evident in the Stress Intensity Factor ratios but has a large influence on the Kink Angle values.