共查询到17条相似文献,搜索用时 93 毫秒
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针对工程中广泛应用的浮筏隔振装置,建立柔性基础复杂激励作用下多维耦合浮筏隔振系统的动力学模型。由于浮筏隔振系统在低频范围内减振效果欠佳,为改善浮筏隔振系统的隔振性能,把吸振器引入到浮筏系统。利用子结构导纳综合法分别建立带有动力吸振器、自调谐吸振器和主动式自调谐吸振器的浮筏隔振系统动力学模型。以功率流为指标,研究单频激励下吸振器对浮筏系统功率流传递特性的影响。最后分析多频激励下带有自调谐吸振器的浮筏隔振系统的功率流传递特性。以传递到基础的功率流为目标函数,分析主动式自调谐吸振器在多频激励下的减振效果。仿真结果表明,吸振器对浮筏具有良好的低频隔振效果,吸振器类型不同与安装方式不同对传递到基础的功率流有不同程度的抑制效果。 相似文献
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针对大型船用浮筏隔振系统的声学优化设计问题,从振动能量传递角度出发,研究浮筏隔振系统各子结构参数变化对系统隔振性能的影响,分析振动能量由设备机脚经浮筏隔振系统传至基础的传递规律。采用子结构导纳综合法,建立基于弹性基础的多激励源多自由度浮筏隔振系统动力学模型,通过仿真分析不同子结构参数条件下浮筏系统振动功率流传递特性和变化规律。仿真结果表明:平置式浮筏系统中隔振器刚度、机组和筏体质量、弹性基础板厚度等结构参数对传入基础的功率流影响较大,减小隔振器刚度、增加机组设备、增加筏体质量、增大基础板厚度均可有效降低传入基础的振动能量。 相似文献
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对基于柔性基础的双层隔振系统的功率流传递特性进行了分析,利用有限元分析软件ANSYS计算了传递到基础的功率流,并用概率灵敏度分析方法研究了功率流对隔振系统给定参数的灵敏度,为双层隔振系统的优化设计奠定了基础. 相似文献
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Scour around bridge pier is the main reason for the failure of bridges. The local scour around the pier causes exposure of the foundation and may lead to undermining of the structure. Different types of protection measures such as the provision of raft, apron, sheet piles, etc. can be used as scour protection measures. One of the possible effective bridge scour protection measures is to provide a raft foundation with cut-off walls and provision of flexible stone aprons towards upstream (u/s) and downstream (d/s) sides of the pier. In this study, the effectiveness of various bridge pier scour protection measures using raft and aprons is investigated through hydraulic model studies in the laboratory. The results are compared for various cases, such as a simple pier, pier with raft and extended raft, pier resting on a raft with stone aprons at u/s and d/s of the raft and pier resting on an extended raft with stone aprons on u/s and d/s of it. The comparison of various cases showed that rigid raft with stone aprons on u/s and d/s and extended raft with apron are found to be more effective in reducing immediate scour beyond the rigid raft, thereby giving protection to the bridge piers. 相似文献
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《Engineering Analysis with Boundary Elements》2005,29(9):859-877
In this paper, a new boundary/domain element method is developed to analyse plates resting on elastic foundations. The developed formulation is then used in analysing building raft foundations. For more practical representation, the considered raft plate is treated as thick plate with free edge boundary conditions. The soil or the elastic foundation is represented as continuous media (follows the Winkler assumption). The boundary element method is employed to model the raft plate; whereas the soil is modelled using constant domain cells or elements. Therefore, in the present formulation both the domain and the boundary of the raft plate are discretized. The associate soil domain integral is replaced by equivalent boundary integrals along each cell contour. The necessary matrix implementation of such formulation is carried out and explained in details. The main advantage of the present formulation is the ability of analysing rafts on non-homogenous soils. Two examples are presented including raft on non-homogenous soil and raft for practical building applications. The results are compared with those obtained from other finite element and alternative boundary element methods to verify the validity and accuracy of the present formulation. 相似文献
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基于有限差分法,对某核电站筏板基础工程的大体积混凝土温度场进行了计算;并在此基础上通过温度应力的计算对此工程大体积混凝土进行了抗裂验算;最后,结合此工程对大体积混凝土的温控措施进行了初步探讨。 相似文献
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边界元分层总和法联合解厚筏基础 总被引:1,自引:0,他引:1
本文以无奇点边界元法分析地基厚板,而用分层总和法计算地基沉降,并将两者联系起来,即利用边界元法解出的厚板下的地基反力作为分层总和法的外力,从而求出地基的沉降。经过反复迭代,使之得出沉降计算数值相协调的最终结果。本方法结合两种算法的优点,易于编程,计算时间短,且适应性好,适于任意形状和多种边界条件的厚筏基础。 相似文献
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对变厚度油罐筏板采用16节点实体退化单元进行有限单元法分析.计算结果证明,应用16节点退化实体单元能大大减少了单元数目,大幅度提高了计算效率,并能达到相当高的精度.该研究结果适合大型油罐桩筏基础的计算,具有广泛的应用前景. 相似文献