Abstract
Composite materials used in the present study are fabricated by Aramid short fibers and Unsaturated Polyester resin. The bending strength and energy absorption properties of the composite are studied in this paper. From the single-fiber pull-out test it is found that 1mm fiber is not long enough to reinforce the polyester, thus the strength of the composite made of 1mm fiber does not increase when compared to that of the resin. But the strength of the composite made of 3mm fiber starts to increase when compared to that of the resin. The strength and absorbed energy always increases with the length and content of the fiber. Some fiber surface treatments are done in order to increase the bonding between the fiber and the matrix. It is found that these treatments affect the interfacial shear strength and fiber strength simultaneously. As strength is an important property of a new material, the effect of these treatments on the strength is discussed in this paper. The bending strength of the composite is assumed to depend not only on the interfacial shear strength but also on the fiber strength, depending upon the length of the short fibers.
