Design of curvilinear variable-stiffness composites considering stiffness, strength and manufacturability

The design of manufacturable variable-stiffness (VS) composite with stiffness and strength requirements is still challenging work. This paper presents an optimization method to achieve such a design, in which the Tsai-Wu strength failure criteria and manufacturing requirements are simultaneously integrated into the compliance minimization problem. A novel parameterization scheme based on the compactly supported radial basis functions is proposed to make the design variable bounded so as to conveniently solve the optimization problem by the gradient-based solver. Owing to the proposed parameterized scheme, the fiber continuity is inherently ensured. Other manufacturing requirements are related to its curl and divergence operations and are easily simplified as the point-wise constraint forms. Further, global strategies based on the p-norm aggregation approach are adopted to handle thousands of local strength constraints and manufacturing constraints. The designs of minimizing the compliance without or with manufacturing constraints, and maximizing strength without or with manufacturing constraints are also conducted and compared. Meanwhile, the effects of the number of the support points, support radius, initial design are also investigated. Numerical results indicate that the effectiveness of the proposed optimization method for designing curvilinear VS composite structures considering the strength, stiffness, and manufacturability.