A NURBS-based level set method for the manufacturing-oriented thermal buckling optimization of curvilinear fiber composite panels with cut-outs

Laminate composite panels with arbitrary cut-outs in a thermal environment may suffer buckling failure because of thermal stress. To address this issue, a manufacturing-oriented thermal-buckling optimization model is proposed for the design of curvilinear fiber paths. Furthermore, instead of using the traditional finite element method (FEM) with high computational costs, a cut non-uniform rational basis spline (NURBS) element method was developed for the thermal buckling analysis of laminate composite panels with arbitrary cut-outs. In this method, a level-set function, segmented density interpolation formulas, and an artificial shear correction factor were developed to describe arbitrary cut-outs, to overcome localized eigenmodes, and to avoid shear locking. Furthermore, a NURBS-based level-set method was proposed to illustrate the curvilinear fiber paths. The norm of the gradient vector of the NURBS-based level-set function was used to express the gap/overlap constraint. Subsequently, a thermal buckling optimization framework with compliance and manufacturing constraints was formulated. The effectiveness of the proposed optimization framework was verified numerically.