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以由中心刚体与柔性板构成的刚柔耦合系统为对象,研究了零次近似模型和耦合模型在动力学方程以及实际计算中表现出来的差异.首先,从连续介质理论出发,在变形位移中,计及了在结构动力学中被忽略的变形位移的附加耦合项,建立了由中心刚体与柔性板构成的刚柔耦合系统的一次近似动力学模型.用一致质量有限元法对柔性板进行离散,基于Jourdain速度变分原理推导出大范围运动为自由的柔性板刚柔耦合动力学连续变分方程.通过数值仿真研究中心刚体和柔性板的大范围运动和变形运动的规律,揭示刚柔耦合动力学性质.通过数值对比,指出了零次近似模型的局限性. 相似文献
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The flutter instability and response of finite-span flexible plates in uniform flow are investigated experimentally. The effects of the plate aspect ratio on its dynamic responses are mainly analyzed. A hysteretic phenomenon is observed and can be described such that the plate flutters spontaneously as the flow velocity is greater than a critical value UC and the plate returns to its stable state as the flow velocity is slowly decreased to another critical one UD. We find that the aspect ratio has a greater effect on UC than on UD. The flutter frequency decreases and the amplitude increases with the increase in the flow velocity. When the flutter instability of the plate occurs, three typical flutter modes are identified and are associated with the aspect ratio and the flow velocity. 相似文献
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Cu(In,Ga)Se2 Thin Films on Flexible Polyimide Sheet: Structural and Electrical Properties versus Composition 下载免费PDF全文
The structural and electrical properties of Cu(In,Ga)Se2 (CIGS) films grown on polyimide (PI) sheet using the three-stage co-evaporation process are investigated by x-ray diffraction spectra (XRD), scanning electron microscopy (SEM), Raman spectra, and Hall effect measurements, respectively. The results show that the properties of CIGS films on PI sheet are strongly dependent on the compositional ratio of Cu/(In+Oa) (Cu/Ⅲ). In contrast to the non-stoichiometric CIGS films, stoichiometric CIGS films show better structural and electrical properties, such as a relatively larger grain size, lower resistivity and higher carrier concentration. The flexible CIGS solar cells on PI sheet with the conversion efficiencies of 9.7% and 6.6% are demonstrated for the CIGS absorber layer with Cu/Ⅲ of 0.96 and 0.76, respectively (active area, 0.20cm^2). The cell efficiency for Cu-poor CIGS films is limited by a relatively lower open circuit voltage and fill factor. 相似文献
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JIN Guoyong YANG Tiejun LIU Zhigang JI Zhenlin LIWanyou 《声学学报:英文版》2007,26(2):138-157
The structural-acoustic coupling characteristics, mechanisms, effect of structural-acoustic coupling on natural mode and natural frequencies of the system are analyzed theoretically and numerically. Formulae for the natural frequencies of the coupled system are derived. Some new conclusions are obtained. Analytical results demonstrate that the strongly coupled system indicates obvious closed-loop feedback characteristics, whereas the weakly coupled system indicates obvious feedforward characteristics, and it is because of the presence of the feedback loop that the natural characteristics and natural frequencies are changed. Cluster coupling characteristic between the structural and acoustic modes for the regular cavity and panel system is found, which determines the coupling interaction between the flexible panel and cavity. Any mode in one mode cluster only interferes the modes and the modal natural frequencies in the same cluster independently. The modal cluster coupling changes not only the natural frequencies of the system but also the modal order and structural mode shape. 相似文献
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Yong Xie Tong Zhao Guoping Cai 《Acta Mechanica Solida Sinica》2011,24(5):467-476
The internal balance technique is effective for model reduction in flexible structures, especially those with dense frequencies. However, due to the difficulty in extracting the internal balance modal coordinates from the physical sensor readings, research so far on this topic has been mostly theoretic and little on experiment or engineering applications. This paper, by working on a DSP TMS320F2812-based experiment system with a flexible plate and bringing forward an approximating approach to accessing the ... 相似文献
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基于模态耦合法建立了考虑对侧柔性壁板的矩形封闭腔体声固耦合模型,导出了耦合系统声振响应随柔性板材料属性及厚度变化的近似关系.通过数值仿真计算,详细分析了单柔性板-单侧激励、双柔性板-双侧激励及双柔性板-单侧激励三种情况下板的轻量化设计对系统声固耦合特性及腔内声压响应的影响.结果表明:对于单柔性板-单侧激励及双柔性板-双侧激励情况,低频段腔内声压主要取决于板厚,其次是杨氏模量,而与板密度关系较弱.因此使用适当增厚的轻质板可以同时达到减重和低频区降噪的目标.对于双柔性板-单侧激励情况,适当的轻量化设计可以显著增强两板间低频段振动的耦合,从而降低该频段的声腔模态响应及腔内噪音.在中高频段,增加板厚和材料密度对降低三种情况的腔内声压均有利。 相似文献
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