Biaxial failure response of composite laminates

• Main Author: Goh, Wee Ter
• Other Authors: Sridhar Idapalapati
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/61296
• Institution: Nanyang Technological University

In this report, a modified arcan test-setup is designed and fabricated to investigate the fracture behaviour of glass fibre reinforced epoxy matrix composite (GFRP) laminates in mode I (tensile) loading, mode II (shear loading) as well as mixed-mode loading. Arcan test jig is chosen as this setup allows the extracting of fracture properties in various modes using only only one shape and size of specimen. Bi-directional and uni-directional specimens are used for the tests in the study. Finite element modelling using commercial software package ABAQUS was also used to obtain critical loads and fracture toughness values and subsequently geometrical factors for various loading conditions. Together with average critical loads obtained, the inter-laminar fracture toughness values of mode I, mode II and mixed mode conditions are calculated and compared. Next, the instrumented biaxial test system is described alongside with the design and fabrication of adaptors to fix the transverse loading arms to the new INSTRON testing machine. Different curing methods to achieve a better quality of biaxial test specimen is also discussed in the report. The material used for this project is GFRP 17500 composite laminates, and various equipment have been used to cure the composites, ranging from autoclave oven, curing table and manual convection oven.