With the advance of manufacturing techniques, quasi-perfect thin-walled structures with initial geometrical imperfections are widely used in engineering. However, much experience is needed to introduce proper perturbations to consider the impact of these undetermined imperfections on structural stability. In this paper, a symmetric secant stiffness method considering the accumulated stress gradients is established through energy approach. With this approximation of the exact stiffness matrix, natural perturbations can be introduced into stability analyses. Numerical examples and experimental comparisons demonstrate that the proposed method can obtain reasonable results for quasi-perfect thin-walled structures merely based on perfect geometrical models.

随着制造技术的进步，具有初始几何缺陷的准完美薄壁结构已在工程中广泛使用。但是，需要大量经验来引入适当的扰动，以考虑这些未确定的缺陷对结构稳定性的影响。本文通过能量法建立了考虑累积应力梯度的对称割线刚度法。利用精确刚度矩阵的这种近似，可以将自然扰动引入稳定性分析中。数值算例和实验比较表明，所提出的方法仅基于完美的几何模型，就可以对准完美薄壁结构获得合理的结果。