Effects of Shallow Bi-Angle, Thin-Ply Laminates on the Structural Performance of Composite Wings

Thesis (Master's)--University of Washington, 2016-06

In this study, we investigate the enhancement of mechanical properties that shallow bi-angle, thin-ply laminates bring to fiber reinforced polymer composites. Coupon- and structural-level tests are conducted along with numerical simulations. According to the coupon tests, we find that shallow bi-angle fibers and thin plies can increase the axial stiffness of laminates significantly at the cost of relatively small decrease in their transverse and shear moduli. For the structural tests, we fabricate composite wing structures using an out-of-autoclave vacuum assisted resin transfer molding process. By conducting static bending tests, we show superior structural performances of the wing structure that employs shallow bi-angle fibers and thin-ply fabric, compared to those that use conventional fiber-angle and thick plies. Shallow bi-angle and thin-ply technologies can open new routes to designing composite structures with improved stiffness and strength with fast and cost-effective fabrication processes.