The Effect of Mechanical and Physical Properties of Polymers on Stress Amplification Factor in Composites with an Internal Damage

The effect of mechanical and physical properties of polymer matrices on stressamplification factors is studied in a composite monolayer. The lamina is subjectedto an elliptical damaged zone of radii “a ” and “b ” while loaded at infinity by a force “P”. The matrix takes both axial and shear loads. The ratio of a/b is allowed to vary in a range of a/b, to simulate almost a crack and a circular hole, for the two values of a 0 and a=b, respectively. Any reduction in stress amplification factor Kr, and peak shear stress in the matrix (Sxy)max, appears to well depend on the value of matrix to fibre volume frac-tion Vm/Vf, and their mechanical properties, as well as shape and size of the hole. For polypropylene and epoxy matrices, at a/b = 0.5 and r = 5, increasing Vm/Vf from 0.5 to 2.0 decreases (Sxy)max by 62 % and 73%, respectively, while Kr is decreased by 17%