Non-destructive testing of defective composite materials

• Main Author: Tan, Wayne Kian Keat
• Other Authors: Brian Stephen Wong
• Format: Final Year Project
• Language: English
• Published: 2018
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/74745
• Institution: Nanyang Technological University

Composite materials have many applications in the aviation industry in the present day. They are commonly used to make the structures aircrafts. For safety reasons, the structures of the aircraft are checked regularly for damages and defects to prevent accidents from happening. Visual inspections are only able to check for surface defects as they are not effective in detecting and identifying defects that are hidden deep inside the material. Hence just visual inspection by itself is not enough as one of the most common defects found in composite laminates is delamination. Delamination can occur at any layers inside the material. Non-destructive testing is currently one of the conventional way to seek out these defects. For this report, the author will be using ultra sonic testing in the form of A-scan and C-scan to detect delamination. Different types of probes of different frequencies will be used to determine their effectiveness in detecting both near surface delamination and normal delamination. To conduct the experiment, Carbon Fibre Reinforced Polymer laminate and Glass Fibre Reinforced Polymers laminate are specially fabricated with defects inside them. Defects of different sizes are carefully implanted in different layers in the specimens to test the limitations of the probes, A-scan and C-scan machine.