Uniform Multiple Laminates Interpolation Method for Angle Optimization of Double-Double Composite Laminates Based on Multi-Material Topology Optimization Strategy

Double-Double laminates present an innovative laminate layup, incorporating a repetition of sub-plies featuring two groups of balanced angles.This layup provides composite materials a broad design flexibility together with the ease of design and manufacturing.This paper proposes an optimization design method for Double-Double laminates based on multi-material topology optimization, which can be applied to the angle optimization design of composite structures with Double-Double layups.A uniform multiple laminates interpolation model is proposed to describe the certainty of the layer direction of composite laminates.The uniform multiple laminates interpolation has the additional advantage when dealing with multi-area and multi-layer composite structures, as it significantly reduces the number of calculations required and eliminates the need for adding interlayer constraints during optimization.The stiffness matrix of each combination of angles for Double-Double laminates is interpolated to form virtual laminates.The sensitivity of the optimization problem with the objective of minimizing the compliance is derived.Finally, the method was applied to the design of composite stiffened panels and composite Unmanned Aerial Vehicle wing.The optimal results show that the optimized Double-Double laminates can get better performance than the Quad laminates with the same percentage of angle.