CHANGE IN STRAIN OF SHORT FIBER-RUBBER COMPOSITE UNDER DYNAMIC FATIGUE

The change in strain of short fiber-rubber composites under repeated constant load was investi-gated. The short fibers in the composites were oriented to the uniaxial direction. The fatigue test of composites was carried out in the direction of fiber orientation under 25 Hz of frequency and 6±2, 8±4 and 10±2 MPa of sinusoidal load. The change in strain of composites under-fatigue test was characterized with two stages, i.e. the strain linearly increased with increasing cycles at the initial stage, and then the strain showed marked increase deviating from an extrapolated straight line at the higher cycles. It seems that the former was caused by the deformation of interfacial region between fiber and rubber, and the latter was taken place by the destruction of interfacial region. This change in strain was restrained by the RFL-treatment and high loading of short fibers. It was also found that under the dynamic fatigue of large displacement, the destruction of interfacial region occurred at the early stage, since the interfacial region was difficult to deform with the displacement of sinusoidal stress.