Free vibration of laminated composite plates with a hole and a delaminated hole

• Main Author: Lim, Jonathan Zhen-Yang.
• Other Authors: Chai Gin Boay
• Format: Final Year Project
• Language: English
• Published: 2011
• Subjects: DRNTU::Engineering::Aeronautical engineering::Materials of construction
• Online Access: http://hdl.handle.net/10356/45937
• Institution: Nanyang Technological University

This report explores the aspect of vibration testing of Carbon Fiber Reinforced Polymer (CFRP) composite laminates. The test specimens were square composite plates that consisted of eight layers unidirectional layup. The aim is to study the natural frequency of these composite specimens across various mode numbers and to investigate the effects of the composite square plates in terms of hole cutout, delamination size and delamination location. CFRP square specimens with various parameters such as different hole sizes and delamination areas are observed. In this project, a test-rig for vibration testing of composite plates was designed and manufactured. The various CFRP plate specimens were also fabricated. This included specimens with different hole cutouts, along with the presence of delaminations. The CFRP square specimens were put through vibration testing using an accelerometer and impact hammer. The boundary conditions simulated were C-C-C-C (all edges clamped) and C-F-C-F (clamped-free-clamped-free). Results from Finite Element Modeling (FEM) simulation and experimental analysis were gathered and compared. It was discovered that by varying the parameters such as hole diameter, delamination size and delamination location, the natural frequency of the CFRP specimens will change accordingly. The introduction of such variables will cause a change in vibration behavior across different mode numbers.