Thin-walled structures are extensively used in aerospace, automotive and mechanical engineering applications due to their high strength- and stiffness-to-weight ratios. However, the performance of these structures tends to be heavily influenced by localised features such as manufacturing defects or design details included for non-structural reasons, e.g. inspection cut-outs. Understanding the sensitivity of structural performance to these nominal stiffness variations, and especially their spatial distribution through the volume of the structure, is important to the designer. We propose a new methodology, the Localised Nominal Stiffness method, to quantify the sensitivity of buckling performance to the distribution of nominal stiffness variations across the structure. The underpinning idea involves reducing the stiffness in small localised regions of the structure and quantifying the ensuing variation in linear buckling capacity before returning the stiffness to its original value. The process is repeated for all locations ensuring coverage of the entire structural domain, which leads to a sensitivity map. In practice, each location corresponds to an element in a finite element mesh. Focusing on structures subject to buckling constraints, and with the aim of using highly efficient structural analysis, we identify sensitivities using the hierarchical Unified Formulation. The resulting sensitivity contour maps can be used to identify regions of the structure where defects or removal of material (for lightweighting) would not significantly affect buckling and post-buckling performance. The effectiveness of the method is tested through three examples: a simply-supported plate; a simply-supported, thin-walled box-section column; and a thin shell with simply-supported and clamped boundary conditions. In all cases, the buckling performance of structures can be maintained with reduced structural weight.

薄壁结构因其高强度和刚度重量比而广泛用于航空航天、汽车和机械工程应用。然而，这些结构的性能往往受到局部特征的严重影响，例如制造缺陷或出于非结构原因包括的设计细节，例如 检查切口。了解结构性能对这些标称刚度变化的敏感性，尤其是它们在结构体积中的空间分布，对设计师来说很重要。我们提出了一种新方法，即局部标称刚度方法，以量化屈曲性能对整个结构标称刚度变化分布的敏感性。基本思想包括降低结构小局部区域的刚度，并在将刚度恢复到其原始值之前量化线性屈曲能力的随后变化。对所有位置重复该过程，确保覆盖整个结构域，从而生成灵敏度图。实际上，每个位置对应于有限元网格中的一个元素。关注受屈曲约束的结构，为了使用高效的结构分析，我们使用分层统一公式确定敏感性。由此产生的灵敏度等高线图可用于识别缺陷或材料去除（用于轻量化）不会显着影响屈曲和屈曲后性能的结构区域。通过三个实例验证了该方法的有效性：简支板；简支薄壁箱形截面柱；和一个带有简支和夹紧边界条件的薄壳。在所有情况下，可以通过减轻结构重量来保持结构的屈曲性能。我们使用分层统一公式确定敏感性。由此产生的灵敏度等高线图可用于识别缺陷或材料去除（用于轻量化）不会显着影响屈曲和屈曲后性能的结构区域。通过三个实例验证了该方法的有效性：简支板；简支薄壁箱形截面柱；和一个带有简支和夹紧边界条件的薄壳。在所有情况下，可以通过减轻结构重量来保持结构的屈曲性能。我们使用分层统一公式确定敏感性。由此产生的灵敏度等高线图可用于识别缺陷或材料去除（用于轻量化）不会显着影响屈曲和屈曲后性能的结构区域。通过三个实例验证了该方法的有效性：简支板；简支薄壁箱形截面柱；以及带有简支和夹紧边界条件的薄壳。在所有情况下，可以通过减轻结构重量来保持结构的屈曲性能。由此产生的灵敏度等高线图可用于识别缺陷或材料去除（用于轻量化）不会显着影响屈曲和屈曲后性能的结构区域。通过三个实例验证了该方法的有效性：简支板；简支薄壁箱形截面柱；以及带有简支和夹紧边界条件的薄壳。在所有情况下，可以通过减轻结构重量来保持结构的屈曲性能。由此产生的灵敏度等高线图可用于识别缺陷或材料去除（用于轻量化）不会显着影响屈曲和屈曲后性能的结构区域。通过三个实例验证了该方法的有效性：简支板；简支薄壁箱形截面柱；和一个带有简支和夹紧边界条件的薄壳。在所有情况下，可以通过减轻结构重量来保持结构的屈曲性能。