A study of the mechanical behaviour of a glass fibre reinforced polyamide 6,6: Experimental investigation

In this experimental work, we studied the mechanical behaviour of a short glass fibre reinforced polyamide frequently used in the automobile industry. In order to investigate the influence of glass fibre content, temperature and strain rate, we carried out a series of uniaxial tensile loadings on an unfilled polyamide and glass fibre reinforced polyamide with different weight fractions: 15, 30 and 50 wt%. Experimental results showed that the studied composite is a strain rate, temperature and fibre volume fraction dependant material. Both elastic modulus and tensile strength increase with strain rate and decrease with temperature. Glass fibre reinforced PA66 exhibits improvement in its mechanical strength. The evolution of the normalized modulus and tensile strength as functions of relative density can be described by a type of power function. The acoustic emission (AE) technique, which is recognized as an effective tool for non-destructive testing and material evaluation, has been used to determine the damage threshold and obtain information about fracture mechanisms in the studied composites. Scanning electron microscopy (SEM) analysis was made on the fracture surfaces to visualize the damage process: fibre fracture, matrix rupture and interface rupture.