Three-dimensional (3D) braided composites have been widely used in the aeronautics and astronautics industries, especially as components in hot-pressing conditions. However, its mechanical performances are specially affected under high temperatures. This work proposes to detect the influence of thermal oxygen aging on residual mechanical behaviors and failure mechanisms of 3D five-directional braided composites with different braiding parameters using the multi-scale method. Firstly, a micro-scale theoretical mass loss model was developed to predict the mass loss, and the effective mechanical properties of the fiber bundle were calculated using the Mori-Tanaka model. Moreover, meso-scale parameterized model was established to capture the damage evolution and predict residual mechanical responses. Finally, the compressive experiments of aged composites were conducted to verify theoretical and numerical models. The results concluded that as the aging days increased, the compressive performance continuously decreased, and the degradation of performance retention rate slowed down. The resin plasticization and interface debonding were primary factors to result in the decline of mechanical performances of composites. The effect of thermal oxygen aging on composites with small braiding angle was more significant. The theoretical and simulation strategies could effectively predict aging behaviors of component structures and residual mechanical properties.

三维 (3D) 编织复合材料已广泛应用于航空航天工业，特别是作为热压条件下的组件。然而，其机械性能在高温下尤其受到影响。这项工作提出使用多尺度方法检测热氧老化对具有不同编织参数的 3D 五向编织复合材料的残余力学行为和失效机制的影响。首先，开发了一个微尺度理论质量损失模型来预测质量损失，并使用 Mori-Tanaka 模型计算了纤维束的有效力学性能。此外，还建立了细观参数化模型来捕捉损伤演化并预测残余机械响应。最后，进行了老化复合材料的压缩实验，以验证理论和数值模型。结果表明，随着老化天数的增加，抗压性能不断下降，性能保持率下降速度减慢。树脂塑化和界面脱粘是导致复合材料力学性能下降的主要因素。热氧老化对小编织角复合材料的影响更为显着。理论和仿真策略可以有效地预测部件结构的老化行为和残余机械性能。并且性能保持率的下降减缓。树脂塑化和界面脱粘是导致复合材料力学性能下降的主要因素。热氧老化对小编织角复合材料的影响更为显着。理论和仿真策略可以有效地预测部件结构的老化行为和残余机械性能。并且性能保持率的下降减缓。树脂塑化和界面脱粘是导致复合材料力学性能下降的主要因素。热氧老化对小编织角复合材料的影响更为显着。理论和仿真策略可以有效地预测部件结构的老化行为和残余机械性能。