EFFECTS OF MATERIAL PROPERTIES AND CRUSH CONDITIONS ON THE CRUSH ENERGY-ABSORPTION OF FIBER-COMPOSITE RODS

Crushing along the fiber axis of unidirectional E-glass fiber composit e rods was examined to determine the effects of fiber volume fraction, fiber diameter, matrix compressive yield strength, crush rate, fiber surface treatment, and crush plate geometry. The volume specific energ y absorption was found to increase with fiber content, fiber diameter, matrix yield strength, and crush rate. The crush load stability was f ound to be independent of fiber content and fiber diameter but not of matrix yield strength. The crush load became less stable as the yield strength increased. The crush behavior of specimens containing clean f ibers was about the same as with sized fibers, but specimens with a re lease agent on the fiber surface crushed with less energy absorption t hat decreased even as the fiber content increased, but the crush load was more stable than with sized or clean fibers. The volume specific e nergy absorption was greater when the rod specimens were crushed again st concave surfaces than against a flat plate. A relatively simple mod el was able to account for the dependence of the energy absorption on fiber volume fraction and matrix yield strength.