复合材料框架结构是飞行器主承力结构实现大尺度和轻量化的理想结构形式，轻量化与动力环境高可靠性设计是其关键设计需求。现有框架结构优化主要基于传统隐式拓扑优化方法，引入密度场、水平集函数或基结构杆件刻画结构分布，不可避免的存在维数灾难、组合爆炸及几何边界无法精确描述困难。本申请旨在基于显式拓扑优化方法，在材料微结构参数及框架构型两个几何尺度上，开展并发的多尺度拓扑及边界不确定性下可靠性优化研究。主要研究内容包括：①构建离散复合材料夹芯组件几何模型，建立显式拓扑描述下复合材料框架结构多尺度并发优化模型；②考虑制造缺陷、环境温度等影响，建立边界不确定性条件下均匀与非线性概率显式摄动模型，发展高效可靠性分析方法；③针对飞行器避开结构共振性能需求，建立考虑频率特性的复合材料框架结构多尺度拓扑及可靠性优化模型。研究成果将发展复合材料多尺度优化设计理论、方法，推动轻质、高可靠性复合材料框架结构的工程应用。

The composite frame structure is an ideal main load-bearing structure for aircraft to achieve large-scale and lightweight. The high-reliability design of lightweight structure under a dynamic environment is the key requirement for such structure. The existing research works on composite frame structure design optimization are mainly based on the traditional implicit topology optimization methods. Which depict the structural distribution by introducing the definition of the corresponding density field, level set function, or primary structure members in the entire design domain, this inevitably introduces a large number of design variables of dimensional disaster or combined explosion. Based on the explicit topology optimization method, the present application is to carry out the study of concurrent multi-scale topology and reliability optimization by considering boundary uncertainty on two geometrical scales. They are the micro-scale material parameters and macro-scale frame configuration, respectively. The main research contents include: ① Construct a geometric model of discrete composite sandwich components, based on which the present research will establish a concurrent multi-scale optimization model under corresponding explicit topology description for composite frames. ② Considering the effects of manufacturing defects, extreme temperatures, etc., the present study will construct uniform and non-linear probability explicit perturbation models under boundary uncertainty and develop efficient reliability analysis methods. ③ Given the requirement of aircraft structure to avoid structural resonance performance, the multi-scale topology and reliability optimization model for composite frames under the maximum dynamic frequency characteristics is established. The research results will develop the design theory and method of multi-scale design optimization of composite structure/material, and promote the engineering application of lightweight, and high-reliability composite frame structures.