Vibration optimization of laminated composites with curvilinear reinforcing fibers for shell structures

Abstract

Tailored Fiber Placement (TFP) is an embroidery technique that enables it possible to design free fiber shapes on base material sheets. The TFP generally creates curved fibers on a flat surface. However, CFRP structures are often used as shell structures rather than as flat plates, and there is not enough research to design fiber shapes on curved surfaces. In this research, we applied our previous optimization method for curved fiber shapes to shell structures. Curved fiber shapes were created by the linear combination of radial basis functions (RBFs) to represent complex fiber shapes. The fiber shape on a curved surface was represented by projecting the fiber shape on a plane surface using a coordinate transformation technique. Using this method, we investigated optimum fiber shapes to improve the first natural frequency of shell structure composites. The results showed that the optimum fiber shape gave higher natural frequencies than the linear fiber orientation. Obtained optimum fiber shape resulted in higher natural frequencies than the linear fiber orientation.