| Lightweight component is now becoming a developing trend for railway transportation industry. Being an important lightweight material, sheet molding compound(SMC) has already been widely used.In this dissertation, properties and molding processs of SMC were investingated in order to manufacture SMC products for railway transportation industry.(1)Influencing factors about mechanical properties, electrical properties, flame retardant properties and wave-transparent properties of SMC were discussed. Along with the increase of fiber proportion and length, the mechanical properties of SMC improved obviously. Increase of filler proportion could slightly improve the tensile strength and flexural strength, but impact strength could be improved when not exceeding 40%. The electric resistance of SMC could be influenced by fiber and filler proportion. Electric breakdown strength could be influenced by environmental temperature and humidity. Aluminum hydroxide filler could influence dramatically on the flame retardant properties which could achieve V-0 with above 30% aluminum hydroxide of SMC. The increase of fiber and filler proportion could also increase the dielectric constant and loss of SMC.(2) Simulation of compressing molding process about railway transportation responder was done by Moldflow. According to flow and pressure distribution from the simulation, processing pressure was determined as 18.36 MPa.(3) Compressing temperature was confirmed according to T-? extrapolation method by DSC data combined with thickening and curing system. Press timing was determined by viscosity test. According to the research about the influence of press timing, pressure maintain time, compressing temperature and closure pressing speed on product mechanical properties and surface quality, the best processing parameters were: press timing 15 s, pressure maintain time 10 min, compressing temperature 155? and closure pressing speed 10mm/s.(4) Railway transportation responders were trial-manufactured by selfprepared SMC and their appearance, properties and type tests were done. The results showed that self-prepared SMC is suitable for railway transportation responder. |
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