Modulating the Buckling Energy Barrier in Thin-Shell Structures Through Local Imperfections

Thin-shell structures, integral to ultra-lightweight deployable systems, face challenges due to their extreme sensitivity to imperfections, which can significantly influence their buckling stability. We employ a perturbation approach to quantify the effects of local geometric imperfections on the buckling energy barrier. A probing methodology is used to map stability landscapes, quantify energy barriers, and explore the buckling behavior of both perfect and imperfect geometries. Through finite element simulations, this study demonstrates how localized imperfections can either enhance or erode the buckling energy barrier depending on their location, amplitude, and width. Negative dimples significantly lower the resistance to buckling, which often results in an early spontaneous collapse, whereas positive dimples mainly enhance stability up to a specific threshold, after which structural integrity is threatened. Furthermore, we demonstrate that the influence of the width of the imperfection follows three distinct regimes and that there exists a critical threshold beyond which the minimum load required to initiate buckling under disturbances increases. The findings provide effective strategies to utilize imperfections for modulating the buckling energy barrier, thus enhancing the performance of thin shells.