Ultrasonic NDT of composite laminates using phased-array probes
Foo, Chuan Xiong
Date of Issue2016-05-12
School of Mechanical and Aerospace Engineering
Fiber-reinforced plate (FRP) or composite material is rapidly gaining tractions in many industries and has become a favorite for big industries like the aerospace industry with even the fuselage of commercial plane made fully of composite material. However, its non-homogenous material also introduced many defects that are largely invisible to naked eyes. Thus the need of ultrasonic NDT (UT) that can a user be able to detect this defect. By using ultrasonic wave and its sensitivity to the change in attenuation, can a user detect these invisible defects. Besides the introduction of these invisible defects, properties of composite materials also play by another different sets of rules. In particular, the relationship between porosity and tensile strength, something that is less relevant in conventional materials but not in composite materials due to its structure. Thus by experimenting the usage of UT to find the attenuation of the material, one can then determine the relevance of the relationship between porosity and tensile strength as porosity will increase attenuation. Like all technologies, improvement to the method is always there and for UT, is the introduction of a wheel based probe. However, this wheel probe, while easier to use in a flat surface, poses problem on tight curved surface that asks for more improvement to the design.
Final Year Project (FYP)
Nanyang Technological University