Numerical study on filling process in progressive compression method

Abstract

A modified vacuum infusion (VI) process, which we refer to as the progressive compression method (PCM), has been proposed to reduce the filling process. In PCM, the bag is divided into several segments. During infusion, all segmented bags are pulled upward by the vacuum. Resin is easily infused into the loose preform. Once enough volume of resin is infused, the vacuum on the segmented bags is released in a step-wise manner. The atmospheric pressure is progressively applied on the segmented bags that are inflated to squeeze the surplus resin from the wetted preform through the dry preform. The flow enhancement is achieved since the dry preform remains loose during the filling process. Once the preform is fully saturated, the post-filling stage is performed for achieving the uniform thickness of the part. In the present study, seven cases is utilized to investigate the effect of three key process variables, including the number of the compression segment, initiating timing of the next segmented compression and volume of infused resin, on the complete filling process. Numerical results show that the multi-segment compression and appropriately premature initiation of the next segmented compression can reduce the filling process; whereas, the excess infused resin can significantly increase the total filling time due to the very slow post-filling stage. Compared with the traditional VI process, PCM at the optimal case reduces the filling time by 10.15% with the same resin consumption as VI.

Keywords:

• vacuum infusion
• filling process
• numerical simulation