In this paper, a multi-objective probabilistic design optimisation approach is presented for reliability and robustness analysis of composite structures and demonstrated on a mono-omega-stringer stiffened panel. The proposed approach utilises a global surrogate model of the composite structure while accounting for uncertainties in material properties as well as geometry. Unlike the multi-level optimisation approach which freezes some parameters at each level, the proposed approach allows for all parameters to change at the same time and hence ensures global optimum solutions in the given parameter design space (for both probabilistic and deterministic optimisations) within a certain degree of accuracy. The proposed approach is used in this study to conduct extensive multi-objective probabilistic and deterministic optimisations (without considering safety factors) on a mono-stringer stiffened panel. In particular, a global surrogate model is developed utilising the computational power of a high-performance computing facility. The inputs of the surrogate model are the omega-stringer geometry and the mechanical properties of the composite material, while the outputs are the fundamental linear buckling load (LBL) and the nonlinear post-buckling strength (NPS). LBL and NPS are obtained via detailed parametric finite element models of the mono-stringer stiffened panel; in the nonlinear model, the interface between the skin and the omega-stringer is modelled via cohesive elements to allow for debonding in the post-buckled regime. Extensive multi-objective optimisations are conducted on the surrogate model using deterministic and probabilistic approaches to examine the omega-stringer geometric parameters mostly affecting the system robustness and reliability. The differences between deterministic and probabilistic designs are highlighted as well.

在本文中，提出了一种用于复合结构的可靠性和鲁棒性分析的多目标概率设计优化方法，并在单声道纵梁加劲板上进行了演示。所提出的方法利用了复合结构的全局替代模型，同时考虑了材料特性以及几何形状的不确定性。与多级优化方法冻结每个级别的某些参数不同，该方法允许所有参数同时更改，从而确保在给定的参数设计空间内（针对概率和确定性优化）全局最优解。一定程度的准确性。在本研究中，所提出的方法用于在单纵梁加劲板上进行广泛的多目标概率和确定性优化（不考虑安全因素）。特别地，利用高性能计算设施的计算能力来开发全局代理模型。替代模型的输入是欧米茄纵梁的几何形状和复合材料的机械性能，而输出是基本线性屈曲载荷（LBL）和非线性屈曲后强度（NPS）。LBL和NPS是通过单纵梁加劲板的详细参数有限元模型获得的；在非线性模型中，皮肤和欧米茄纵梁之间的界面通过内聚元素进行建模，以允许在后屈曲状态下剥离。使用确定性和概率方法对替代模型进行广泛的多目标优化，以检查主要影响系统鲁棒性和可靠性的欧米茄纵梁几何参数。确定性和概率性设计之间的差异也被强调。