1996 Volume 45 Issue 5 Pages 490-495
The purpose of the present work is to investigate the effects of matrix resin and fiber content on the behavior of fatigue crack propagation in continuous-glass-fiber-mat reinforced CP-resin composites. For this purpose, ductile matrix resin and brittle one are used. These two kinds of resins have the characteristic that the elastic modulus and tensile strength are nearly the same with each other, while the elongation is different. The composite specimens are made of these resins and continuous glass fiber mat of 20wt.% and 60wt.% fiber contents. The fatigue crack propagation test was conducted by using the tapered DCB specimens to control the stress intensity factor range, ΔK, during the test. The results obtained are as follows;
(1) The relation between the crack propagation rate, da/dN, and ΔK for all the present materials is shown by a straight line in logarithmic representation. (2) For the composites of 20wt.% fiber content, the da/dN of the ductile matrix composite is lower than that of the brittle matrix one at the same ΔK. (3) For the composites with either one of the matrix resins, the ΔK value of the 20wt.% fiber content composites is about 40 percent less than that of 60wt.% at the same da/dN.
