Mechanical and Crash Behaviour of Sheet Moulding Compound Materials

The mechanical and crush behaviour of high-performance sheet moulding compounds (SMCs) was studied. SMC laminates and half tubes were consolidated using a hot press. SMC tubes were made using two half tubes joined together with adhesive bonding and/or mechanical fastening. Both high-toughness SMC (SMC-T) and high-strength SMC (SMC-S) showed excellent tensile and flexural properties under static loading. The fracture toughness of SMC-S was somewhat higher than that of SMC-T, but at room temperature the energy absorption of SMC-T was higher than that of SMC-S. However, the impact strength of SMC-T decreased rapidly with increasing temperature, while that of SMC-S dropped only slightly up to 100° C. Dynamic mechanical thermal analysis (DMTA) results showed that SMC-S maintained its mechanical properties up to 150° C, while the storage modulus of SMC-T reduced rapidly with increasing temperature. SMC tubes were crushed at a speed of 500 mm/min. The specific energy absorption of both SMC-S and SMC-T tubes could reach 50 kJ/kg. The crush strength of the mechanically fastened SMC tubes was much higher than that of adhesively bonded ones.