Boundary element analysis of effects of holes in fiber metal laminates

• Main Author: Gan, Bok Sheng
• Other Authors: Ang Hock Eng
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Aeronautical engineering::Materials of construction
• Online Access: http://hdl.handle.net/10356/16236
• Institution: Nanyang Technological University

Fiber metal laminate (FML) is a new class of structural material that is getting more popular in the aerospace industry due to its high strength-to-weight ratio which enables high potential in reducing total weight and thus reducing costs in the structure. FML possessed high fatigue resistance due to its fiber bridging capabilities, which makes it even more attractive as structural materials in the aerospace industry. It is also well known that introducing holes behind a crack impedes crack propagation significantly. In addition, this method of reducing the stress intensity factor at the crack tip also allows total weight reduction in a structure which may prove to be useful in the aerospace industry. Analysis of a plate with cracks and defects such as holes, pose to be a complex problem due to its multi-connectivity. This kind of problem is therefore suitable to solve using boundary element method with its established high precision. In this project, boundary element method analysis was performed on cracks and the effects of holes in a fiber metal laminate on the plate’s bridging stress and stress intensity factor. Two cases were studied namely, one with holes and the other one with holes. Two kinds of plate were also studied which are the plate with central crack and the other with an edge crack. The size of the holes were varied to study the effects on the bridging stress as well as the stress intensity factor at the crack tip The effect of the location of the holes away from the crack was also studied.