短繊維強化アイオノマー複合材料の引張および疲労特性

抄録

A study has been made on the tensile and fatigue properties of discontinuous carbon fiber reinforced ionomer composites oriented unidirectionally by hand-alignment technique.
The fiber-matrix interfacial shearing strength calculated from the rule of mixture showed considerably lower value than that expected from the good adhesive ionomer matrix. The interfacial shearing strength decreased remarkably with increasing fiber length. It is considered that the fiber-matrix interfacial debonding can arise from the stress concentration at the fiber end, since the fiber overlaps are not perfectly in discontinuous fiber composites, and consequently, the interfacial shearing strength takes a very low value. It seems that the fiber-matrix contacts and the fiber overlaps decrease with increasing fiber length in discontinuous fiber composites oriented unidirectionally by hand-alignment technique.
The low frequency fatigue tests on the unidirectionally oriented composites showed an excellent fatigue strength without braking for N=4×10³ at 65% of ultimate tensile strength.
The dynamic modulus of the fatigued Zn-type ionomer composite showed a 50% decrease against the virgin dynamic modulus at room temperature. The reduction of dynamic modulus may be related to the fiber-matrix debonding. On the other hand, the residual strength retained 90% of the virgin ultimate tensile strength. Even if the interfacial debonding occurs, the fiber could still carry load by the interfacial friction.