Papers by Author: Ai Ping Liu

Abstract: A semi-metallic stainless steel/carbon fiber reinforced PEEK-based friction material was developed in this paper. The composite was PEEK 19.63wt%, stainless steel fiber 7.57 wt%, carbon fiber 10.97 wt%, cashew 6.51 wt% and fillers 55.33%. The molding process was blending for about 30 seconds at higher speed, pre-heating at the temperature of 80
for 30min, molding at 320
and pressure 35Mpa for 3min/mm, then post-curing at the temperature of 80
for 30min , 150
for 30min270
for 30min320
for 180min. The results of abrasion test showed that the developed material N3 had higher and steady friction coefficient and low abrasion value. The SEM morphology study showed that the wear mechanism was particle abrasion at low temperature but adherence abrasion as well as particle abrasion occurred at higher temperature. The cohesive strength of the composite and the heat-resistant property of resin matrix were the key factors affected wear loss. The abrasion depended on the strength of transformed films and matrix.

Abstract: A screw dislocation interacting with a semi-infinite interfacial crack in two dissimilar piezoelectric layers is studied. The complex variable method and the conformal mapping technique are employed to obtain the solution of the problem. The stress and electric displacement intensity factors are given explicitly. We find that the stress and electric displacement intensity factors depend on the effective electro-elastic material constants. Numerical example shows that the influence of piezoelectric effect on the crack tip shielding is significant.