2001 年 50 巻 9 号 p. 988-993
Sheet Moulding Compound (SMC) has been widely applied to industries such as automotive exterior parts and housing facilities for its excellent mechanical properties, relatively low cost and lightweight and good design possibilities.
Typical SMC products have some ribs in order to reduce weight of the structures without loss of stiffness. However, in these products, various problems such as sink mark, weld lines, warpage and heat cracks often occur. These problems are caused by complexity of fibre distribution and fibre orientation. In these cases, while it is needed to change the design of the mould, moulding tools are expensive and moreover it costs greatly to change the design of them. So, CAE system is needed to improve the efficiency of mould design.
But defects of SMC products formed by compression moulding are greatly influenced by moulding conditions, especially material flow. But the material flow of SMC is complex and unsteady. And in ribs, it is more difficult to predict the material flow of SMC and fibre distribution and orientation and so on. Therefore it is useful to apply the database that can express these factors simply. And we are trying to construct the CAE system to predict the stiffness of structure in SMC compression moulding.
In this paper, we investigated mechanical properties in rib part of SMC products. From the results, we constructed a method for estimation of Young's modulus in rib part in consideration of heterogeneity as fibre orientation and its distribution and resin-rich. As the results, in predicting Young's modulus in rib part, we get good agreement with theoretical value and experimental value.