Temperature and moisture effects on the failure of composites

• Main Author: Lui, Man To
• Other Authors: Chai Gin Boay
• Format: Final Year Project
• Language: English
• Published: 2018
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/74559
• Institution: Nanyang Technological University

Composite tidal turbine blades are subjected to seawater degradation and mechanical loadings from the operating environment. However, there is limited research on the effects of moisture and voids on the mechanical properties of composite made using Vacuum Assisted Resin Transfer Method (VARTM). Hence, this project will further explore the correlation between void, moisture and strength of composite material, fabricated from T300 Carbon Fibers and Epikote RIMR 135 resin. The main purpose of this project is to analyse the tensile and flexural properties of Carbon Fiber Reinforced Polymer (CFRP) composite through static tensile and 3-point flexural tests. In this project, all the CFRP composite specimens were fabricated through VARTM. The fiber-to-matrix volume fraction was 45:53 for tensile panel and 47:51 for flexural panel. The wet specimens were immersed in the seawater at 60°C for 30 days before the experimental testing. The void content was significantly high in the specimens near the resin port, which introduced higher moisture content into the composite. It was analysed from the void-moisture-strength correlation that moisture reduced the tensile strength of CFRP composite by up to 15%; and flexural strength by up to 47%. In addition, a further increase in moisture had a significant effect on the tensile strength of composite. This explains the reason to avoid using the portion of the panel near the resin port for the fabrication of tidal turbine blades.