自動車用SMCパネルの引張強度特性に及ぼすSMCシートのチャージ位置と組成の影響

抄録

Tensile strength tests of SMC panels used for an automotive structural component were conducted by changing the charging positions of SMC sheet and its compositions such as low profile additives and fillers. Three kinds of SMC sheets with different types of low profile additives and different amounts of fillers were prepared. Three of charging positions of such SMC sheet were the central part (M), the flat part (F) and the side of ribs and bosses (R) of a metal mold. Test specimens were cut out from these nine kinds of SMC panels. The cutting directions of tensile specimens were perpendicular (90deg. directional specimens) and parallel (0deg. directional specimens) to the rolling up direction of SMC sheet. Statistical analysis of data obtained from tensile tests was carried out based on the concept of two-parameter Weibull distribution. Analysis results are summarized as follows;
(1) For SMC panels molded at charging positions F and R, strength of 0deg. directional specimen is from 2 to 3 times as high as that of 90deg. directional specimen. On the other hand, for SMC panels molded at M, there is little difference between them.
(2) In case of low profile additive of poly-vinyl acetate system, the flow pattern of fibers is inclined not to be uniform and the fracture strain is less than that in the case of styrene butadiene system.
(3) The tensile strengths of SMC panels tend to become lower as the amount of filler of CaCO₃ increased.