Elastomeric microfluidic valve for active resin flow control within composite structure

Abstract

Due to the existence of curvature, non-uniform pressure field forms within fiber reinforced polymer (FRP) composite during processing. Complex resin flow induces significant thickness deviation and defects concentration at corners. In this study, a microfluidic valve based on self-structure was proposed to restrict the mutual flow between regions for thickness uniformity control. Besides, little resin was actively guided to flow towards microfluidic valve, which helped avoid ply wrinkling, evacuate bubbles and enhance the surface quality of composite. By introducing an isolation film with a certain number of micropores on composite surface, the microfluidic valve formed naturally. Its microstructure adjusted self-adaptively to deviate local flow directions, and finally reverted to its initial states. This method allowed composite parts to be manufactured with uniform thickness (Maximum deviation of thickness: 0.01 mm), and without the need for extra hardware.