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通过实验和数值模拟研究了T300碳纤维叶片的抗冲击性能,探讨了碳纤维叶片的变形损伤模式及纤维层数对叶片抗冲击性能的影响。采用明胶鸟弹对不同层数碳纤维叶片开展了冲击实验,基于宏观连续损伤力学理论和Hashin失效准则针对碳纤维材料的失效形式编写了用户材料(vectorized user-material,VUMAT)子程序,采用光滑粒子流体动力学方法模拟明胶鸟弹,运用ABAQUS有限元软件对不同层数碳纤维叶片的动态响应过程进行了数值模拟,在鸟弹冲击过程中叶片变形、鸟流状态、冲击持续时间等方面,模拟结果与实验结果吻合较好。在鸟撞叶片初始冲击阶段,三种不同层数的叶片都有较大的变形,且叶片的变形模式相近;在冲击衰减阶段与恒流稳定阶段,不同层数碳纤维叶片的挠度与断裂位置都有较大差别。在鸟弹冲击叶片过程中,叶片以弯曲和扭转耦合变形模式为主,其中弯曲变形对其损伤破坏起主导作用。实验结果表明,碳纤维叶片损伤模式主要表现为:(1)叶根部边缘损伤,(2)叶根部完全断裂,(3)叶根部与叶顶部完全断裂。碳纤维抗冲击性能受层数的影响较大,通过实验和数值模拟对鸟弹冲击叶片进行机理分析,可为碳纤维叶片的工程设计和应... 相似文献
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Channel state information (CSI) is essential for downlink transmission in millimeter wave( mmWave) multipleinput multiple output (MIMO) systems. Multi-panel antenna array is exploited in mmWave MIMO system due to itssuperior performance. Two channel estimation algorithms are proposed in this paper, named as generalized jointorthogonal matching pursuit (G-JOMP) and optimized joint orthogonal matching pursuit (O-JOMP) for multi-panelmmWave MIMO system based on the compressed sensing (CS) theory. G-JOMP exploits common sparsity structureamong channel response between antenna panels of base station ( BS) and users to reduce the computationalcomplexity in channel estimation. O-JOMP algorithm is then developed to further improve the accuracy of channelestimation by optimal panel selection based on the power of the received signal. Simulation results show that theperformance of the proposed algorithms is better than that of the conventional orthogonal matching pursuit (OMP)based algorithm in multi-panel mmWave MIMO system. 相似文献
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这个季节,如果有人问哪款手机能让人带上音乐,随兴起舞,恐怕大多数人第一个想到的就是索尼爱立信(Sony Ericsson)的W800c。这款造型活泼亮丽的WALKMAN手机,因其突破性的设计,使得音频播放不再是手机附属的玩具功能,而成为时尚一族随时随地欣赏音乐的首选。 相似文献
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