Nonlinear buckling analysis of helicoidal composite panels with curvilinear stiffeners

Abstract

This study introduces a semi-analytical method designed to efficiently and accurately analyze the nonlinear buckling response of complex curvilinear stiffened panel structures, addressing the computational challenges associated with such designs. The proposed method establishes displacement compatibility conditions to couple stiffeners and base plate, while employing Legendre polynomials to expand displacement fields, thereby enhancing robustness and accuracy. The Ritz method is utilized to solve the nonlinear buckling equations, yielding equilibrium path deviations consistently below 5 % compared to finite element method results while achieving a 61.43 % reduction in computation time. Parametric studies conducted under uniaxial and biaxial compressive loads confirm the capability of the method to accurately capture the nonlinear buckling behavior of curvilinear stiffened panels. The findings reveal a reduction in nonlinear critical loads, approximately 20 % lower than those predicted by linear buckling analysis, emphasizing the necessity of nonlinear analysis for accurate system evaluation. The study underscores the potential of the proposed semi-analytical method as a reliable and computationally efficient tool for nonlinear buckling analysis in complex stiffened structures.