Experimental and numerical studies on two-point incremental forming of woven fabric composite sheet

Stamping of fiber reinforced plastic (FRP) composite sheet, especially the woven fabrics and their prepregs, has been extensively researched. However, for small-batch production, high cost and long cycle due to design of complicated molds are still critical issues in composite manufacturing. In this paper, a novel hybrid process is proposed to reduce manufacturing costs and cycles of composite parts in small-batch production with the combination of incremental sheet forming and autoclave process. To verify the process feasibility, two-point incremental sheet forming of a typical pyramid part using plain fabric prepreg was preliminarily studied through experimental and numerical methods. A metal-fiber-metal (MFM) sandwich panel configuration consisting of two dummy sheets and core fabric prepreg layer was used to prevent the woven fabric from directly contacting the forming tool and support die, which can avoid viscous friction and guarantee the practicability of the ISF process. Based on the mechanical properties of the plain weave obtained from uniaxial tension and bias extension tests, a continuous approach-based finite element model (FEM) was established in PAM-FORM. Next, cross section profiles, peripheral outlines and shear angle distributions were extracted from experimental and simulation results. The corresponding comparison results were used to evaluate prediction accuracy of the established FE model. Finally, the influence of fabric layer on dummy sheets, fabric deformation history and the influence of friction coefficient on simulation results were analyzed.