Papers by Author: Bao Chen Sun

Abstract: Measurement of wheel/rail contact forces is of importance. Traditional methods for wheel/rail interaction force measurement all need strain gauges on wheel sets and/or rails. Because strain gauges have the performances of zero-drift, poor anti-interference property and instability of test system, they can’t meet wheel/rail force test requirements in high-speed and heavy haul railways. A new method based on PVDF piezoelectric sensing technology is presented for the test of vertical and horizontal wheel/rail force in this paper. Firstly, based on the wheel/rail interaction characteristics, the restriction condition of track and strain sensing principle of PVDF films, principle for measuring vertical and lateral wheel/rail interaction forces is proposed. Then a series of tests were carried out to compare the performance of PVDF strain sensors with the one of strain gauges. The results show that the PVDF strain sensor has better reliability in wheel/rail force monitoring. Finally numerical analysis by Finite Element Method has been carried out to verify the feasibility of the method presented in this paper.

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.