Abstract: Improving the impact toughness and energy absorption abilities of the composite is very important. In this paper, the improvement of inter-laminar toughness through adding glass-fiber surface mat was investigated. S-4800 field emission scanning electron microscope (FESEM), optical microscopy, compression-shearing, 3-piont bending as well as tensile tests were carried out on the specimens of fiber-glass/resin laminates with and without fiber-glass surface mat, respectively. Fracture morphology showed that specimens with surface mat fractured in the surface mat laminar and short fibers worked as bridges which connect the adjacent layers and the fracture surface were relatively rough. The fiber bridging affected the failure mechanism and increased energy absorption ability. It was observed that the energy absorption of specimens with the surface mat increased by 7.3%. Mechanical tests indicated that the force-displacement slope of specimens with the surface mat became more smoothly and the fracture displacement was bigger as compared to the specimens without the surface mat. The results revealed that adding the surface mat reduced the shear stress and the shear modulus by 15.7% and 24.5%, respectively. Besides, adding the surface mat may decrease the curvature of fiber yarns, which will increase the resistance to fail.

Key words: surface mat, inter-laminar toughness, energy absorption