Stability of Composite Smooth Shells with Peripheral Reinforcement Under Combined Loads

Abstract

In this study, the buckling stability of flat composite shells with a thickness of 5 cm and individual element dimensions of 40 × 200 cm, arranged in an interconnected mesh and subjected to combined loads (axial, lateral, and external pressure), was investigated. Using the First-Order Shear Deformation Theory (FSDT) and numerical implementation in Abaqus, two environmental reinforcement strategies—temperature-dependent and external pressure-dependent functions—were integrated as controllable variables into the model. Nonlinear static analysis revealed that, without environmental reinforcement, the shells experienced sudden collapse at displacements of 7–11 cm. In contrast, temperature-based environmental reinforcement increased the yield load by up to 68%, and after surpassing the linear buckling threshold, the structure exhibited ductile behavior with significantly enhanced energy absorption attributed to the release of residual stresses and more uniform stress distribution across laminates. In the external pressure-based reinforcement model, although the yield load decreased, overall displacement was reduced by 10% and the maximum von Mises stress dropped by 82%, indicating effective mitigation of bending-induced stresses and improved post-buckling stability. Despite their distinct mechanisms, both reinforcement methods induced a qualitative shift in structural behavior—from abrupt, localized failure to controlled, gradual deformation. This study is the first to introduce and validate “environmental reinforcement” in composite shell literature as an active, equipment-free design strategy that transforms ambient conditions from destabilizing factors into performance-enhancing tools. The findings lay a foundation for the development of intelligent roofs, aerospace structures, and resilient systems in civil, aerospace, and defense engineering under complex loading scenarios.