【摘要】 复合材料Ω形柱在碰撞吸能和轻量化方面具有一定的应用潜力，为研究铺层角度和加载速率对复合材料Ω形柱吸能性能的影响，开展了碳纤维复合材料Ω形柱的轴向压缩实验，深入分析了其吸能评价指标及破坏机理。主要研究内容及结果如下：进行了3种铺层角度([0/90]_3s、[0/45/90/-45]₃和[±45]_3s)Ω形柱的准静态和动态压缩实验研究。准静态加载时，[0/90]_3s和[0/45/90/-45]₃铺层角度试样均表现为渐进破坏，而[±45]_3s铺层角度试样表现为非稳态破坏，破坏模式的不同导致其比吸能约为前2种铺层试样的1/2；动态加载时，3种铺层角度的Ω形柱均表现为渐进破坏，且比吸能较为接近。其中，[0/90]_3s和[0/45/90/-45]₃铺层角度Ω形柱在动态加载时的比吸能较准静态分别降低了29.70%和20.97%，而[±45]_3s比吸能较准静态提高了46.10%，破坏模式的转变是其比吸能提高的主要原因。准静态加载时，铺层角度对Ω形柱比吸能有一定影响。而动态加载时，加载速率的影响占主导地位，铺层角度影响较小。更多还原

【Abstract】 shaped composite tubes have certain application potential in terms of collision energy absorption and lightweight.To study the effects of ply orientation and loading rate on the energy absorption characteristics of the Ω-shaped composite tubes, quasi-static and dynamic axial compression experiments were carried out on carbon-fiber-reinforced composite Ω-shaped tubes by using an electronic universal testing machine and a high-speed hydraulic servo testing machine, respectively. In addition, the failure modes and evaluation index relevant to energy absorption were analyzed based on the crushing load-displacement curves and failure morphologies. In the experiments, the Ω-shaped tubes with three ply orientations, namely [0/90]_3s, [0/45/90/-45]₃ and [±45]_3s, were compressed under quasi-static and dynamic loading rates. Under quasi-static loading, the specimens with [0/90]_3s and [0/45/90/-45]₃ ply orientations both showed progressive failure, while the specimens with [±45]_3s ply orientation showed a catastrophic failure mode. The specific energy absorption（SEA） of the specimens with [±45]_3s ply orientation is about half of those of the other two specimens due to different failure modes. Under the dynamic loading, the Ω-shaped tubes with three ply orientations, where the SEA almost remains the same, were all featured by the progressive crushing. Moreover, the SEAs of the specimens with [0/90]_3s and [0/45/90/-45]₃ ply orientations under dynamic loading are reduced by 29.70% and 20.97%, respectively, compared with those under quasi-static loading. However,the SEA of the specimens with [±45]_3s ply orientation is 46.10% higher than that under quasi-static loading. The change of failure modes is the main reason for the increase of the SEA. Under quasi-static loading, the ply orientation has a certain effect on the SEA of the Ω-shaped tube, while under dynamic loading, its influence is relatively weak. The main reasons are as follows. Under a low loading rate, buckling fracture and interlaminar delamination of fiber and matrix gradually occur,resulting in a global response of the structure. On the other hand, under a higher loading rate, the contact time between the Ω-shaped tubes and the indenter is short, leading to a localized response, which is dominated by the loading rate, while the failure mode is less affected by the ply orientations.更多还原