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时速600 km/h高速磁浮列车-轨道梁耦合系统的横向动力学性能对系统安全性、舒适性和经济性有重要影响,有必要建立列车-轨道梁的横向耦合振动统一方程组模型进行研究.基于多刚体动力学,采用矩阵组装法建立246自由度的5节编组列车横向振动微分方程组;基于连续体受迫振动理论,采用模态叠加法建立240自由度的40跨柔性轨道梁的... 相似文献
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目前,对于火灾升温阶段及自然冷却降温过程的温度场变化已经有了一定的研究,而对消防过程中由于消防水作用迅速冷却的温度场分布变化规律的研究还相对较少。本文建立单室结构模型,利用FDS软件中的喷淋系统,模拟消防过程中的喷水灭火,研究了消防灭火过程中室内温度场的变化。模拟过程中考虑初始消防时间、喷头单位时间流量等对空间温度场分布及变化的影响,得到了单室建筑在灭火过程中的空间温度分布和温度梯度变化特点。研究发现,在消防冷却过程中,室内温度场在消防介入瞬间,离消防水较近区域会出现明显的温度骤降,离消防水较远区域温度下降相比较为平缓,造成了空间温度梯度极为不均。 相似文献
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A finite element formulation was presented for the nonlinear free vibration of thin-walled curved beams with non-symmetric open across section. The kinetic and potential energies were derived by the virtual principle. The energy function includes the effect of fiexural-torsional coupling, the torsion warping and the shear centre location. For finite element analysis, cubic polynomials were utilized as the shape functions of the two nodal thin-walled curved elements. Each node possesses seven degrees freedom including the warping degree of freedom. The nonlinear eigenvalue problem was solved by the direct iteration technique. The results are compared with those for straight beams as available in the literature. The results for nonlinear free vibration analysis of curved beams for various radii and subtended angle are presented. 相似文献
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