Paper number 627


Seong Taek Lim, Moon Koo Kang and Woo Il Lee

Department of Mechanical Engineering
Seoul National University, Seoul 151-742, Korea

Summary The void content within RTM parts is responsible for a severe degradation of part strength. Due to the non-uniform permeability of the preform on sub-tow scales, formation of air void highly depends on the resin velocity and the surface tension at the flow front during mold filling. Capillary number is the decisive factor affecting the void formation. In this study, a mathematical model for the void formation as a function of capillary number was developed. Experiment was performed for a one-dimensional flow in which the capillary number varies with the moving flow front. The proposed model could efficiently predict the size and content of air voids. Applied to a body panel of a passenger car, the potential of this model to predict the void distribution in arbitrary shapes is illustrated.
Keywords RTM, voids, permeability, capillary pressure, mold filling, microscopic flow.

Theme : Processing, Integrated Design and Manufacturing

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