2005 Volume 54 Issue 5 Pages 513-517
SMC products generally have some ribs in order to improve stiffness of structures. However, material flow in the molding process becomes very complicated by establishing the rib in the structure. As the result, glass fiber distribution and fiber orientation in rib part change, and it often happens that required stiffness of products does not obtained. In these cases, while it is needed to change mold design, a great amount of time and cost are required. The mold for compression molding of SMC is very expensive because the mold must be able to endure the molding in high temperature and pressure. Then, the development of CAE system, which estimates the stiffness of the SMC structure with the rib from the molding condition and the mold shape is being needed and tried in order to design the mold efficiently.
Each material constant was calculated in the way that Young's modulus of flat plate part was expressed by Fiber orientation, and that of rib part by B/ts. Here, B/ts is the ratio between rib width “B” and material thickness “ts” as the material passes the rib in molding process. When the rib was perpendicularly attached for the SMC material flow direction, these CAE systems were studied, but when the rib is obliquely attached, the systems are not yet studied. So, in this paper we try to estimate the Young's modulus in rib part in consideration of heterogeneity as Fiber orientation and its distribution and resin-rich, when the rib has obliquely been made for the flow direction. The factor (Fiber weight content, Orientation factor and Fiber orientation angle) that influenced Young's modulus in rib part was able to be arranged by B/ts. As the results, we get good agreement with theoretical Young's modulus and experimental Young's modulus in rib part.
