Comparative study of S2 glass plain and twill woven composites under fatigue loading

Woven composites have good properties in mutually orthogonal directions, more balanced properties than unidirectional laminates and have better impact resistance. The use of these composites for primary structural applications in place of conventional laminated composites has been increased considerably in the recent years. They are being manufactured by using new processes such as Resin Infusion (VARIM) and Resin Transfer Molding (RTM). These new processes are low cost, affordable and suitable for high volume manufacturing environment. One of the popular plain woven composites is fabricated using S2-Glass and SC-15 resin system components by using Resin Infusion (VARIM) process. These woven composites are being evaluated for Integral Armor applications. These components are expected to be under fatigue loading. To assess the feasibility of this material manufactured through Resin Infusion (VARIM), it is very important to understand the fatigue behavior of these composite materials. The present study provides comparison of the performance evaluation of plain and twill woven composite material for Integral Armor applications. Tension-Compression (R = -1) fatigue experiments were performed. All the fatigue tests are performed at 1 Hz frequency. S-N diagram and stiffness degradation over the fatigue life of the specimens were obtained.