Crack problems in thin-layered structures

• Main Author: Lai, Alvin Junqi
• Other Authors: Xiao Zhongmin
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Mechanical engineering::Mechanics and dynamics
• Online Access: http://hdl.handle.net/10356/16166
• Institution: Nanyang Technological University

Thin-layered structures are used in a variety of applications today. Prevention of failure of these structures is important by identify the integrity or strength of these structures. The thickness of the crack residing layer, the distance from crack to the layers interface and elastic modulus mismatch all play an important role in the failure of these structures due to subinterface cracks. The investigations made in this report via finite element analysis software ANSYS suggested that Mode I stress intensity factor at crack tip for the five cases in study (centre and edge cracks in bi-layered structures, centre and edge cracks in tri-layered structures and collinear cracks in tri-layered structures) were affected by elastic modulus mismatch, crack-interface distance and also thickness of the crack-residing layer. Due to the difference in modeling, the results obtained differed from literature in bi-layered structure slightly but they conform to general trends available in literature. The tri-layered structure models presented a few unusual trends for some configurations but most of the results obtained followed general trend surveyed in literature. The investigations showed significant influences on crack stress intensity factor by the three factors above. The collinear cracks study suggested stress intensity factors are affected by the combined interactions between the two cracks and the three factors above.