中文摘要：

施工误差、杆件的初偏差等不可控制因素必然导致网壳结构具有一定的初始缺陷．初始缺陷及其随机性是影响结构稳定和承载力的重要因素．基于标准正交基的随机场展开法为理论基础，通过对随机初始缺陷相关结构的分解将其投影在结构屈曲模态正交基上．算例表明，本方法可以用较少的随机变量描述原随机缺陷场，从而全面高效地寻求初始缺陷的最不利分布形式，保证缺陷敏感性结构具有较高的安全可靠性，适用于大型工程结构的随机缺陷分析．

英文摘要：

The uncontrollable factors such as construction errors, the initial deviation of components, etc. will inevitably lead to a certain initial imperfections. It is generally known that the stochastic initial imperfections of the structure are an important factor to affect structural stability and bearing capacity. Since these imperfections are random in nature, this paper proposes the method mainly based on the standard orthogonal basis to expand the stochastic field, and takes into account the decomposition of the stochastic initial imperfections related to structures, which is projected in the buckling modal orthogonal basis. Numerical example shows that this method can use less random variables effectively to describe the original stochastic imperfections field, and efficiently search for the most unfavorable initial imperfection distribution form in order to ensure the imperfection sensitivity structures have a higher reliability. So it can be applied to large-scale engineering structure stochastic imperfection analysis.