Thermal expansion coefficient: A macro-scale indicator of particle filtration in composites fabricated by resin infusion

Abstract

The particle loaded composites are being used widely for tailored properties, however, the particles tend to create concentration gradient along part length during infusion. Keeping in view the limitations of existing characterisation approaches, thermal expansion coefficient (CTE) is used as a macroscopic tool to measure particle filtration for the first time. Composite plates were fabricated by VIM (Vacuum Infusion Moulding) process from glass woven fabric and vinyl ester resin containing silica microparticles (0, 0.5, 1.0, 1.5, and 2.0%). CTE was determined at different positions from composite samples. It was found that the CTE was low at the inlet indicating a high particle concentration. A gradual decrease in the particle concentration was observed from the inlet towards the outlet. The variation of CTE due to the gradient of particle concentration was validated using COMSOL Multiphysics®. Both the experimental and numerical results show a similar global trend, i.e. CTE is decreasing with increase in the particle concentration. Hence the CTE can be effectively used as a qualitative tool for the measurement of particle filtration in the composite part produced by vacuum infusion.

Keywords

• Particle loaded composite materials
• Suspension flow
• Particle filtration
• Numerical methods
• Liquid composite moulding