共查询到20条相似文献,搜索用时 218 毫秒
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研究了水平激励下二维矩形储箱中流体的晃动,抑制晃动的装置为竖向的刚性隔板,建立了隔板在储箱自由液面处的解析模型。首先通过引入人工界面的方式,将流体域划分成若干个流体子域,使每个流体子域对应的速度势函数满足C1连续性条件。基于叠加原理,使用分离变量法求得每个流体子域的速度势的形式解,将形式解代入子域间界面与自由液面条件可得含有待定系数的级数方程,通过加权积分消去方程中的空间坐标,截断方程可得特征方程,由此可得晃动频率与模态。将水平激励下的速度势函数分解为摄动速度势与刚体速度势,将摄动速度势和刚体速度势代入自由液面的波动方程即可求得含广义坐标的动力响应方程,求解该方程可得储箱中流体的晃动响应。 相似文献
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横向流体激励下绳索的动力学分析 总被引:2,自引:0,他引:2
通过分析横向流体对绳索的作用力 ,建立了绳索的动力学方程。借助 Pilipchuk坐标变换 ,使具有零刚度的绳索动力学方程包含静刚度项 ,继而使用两变量摄动方法对绳索运动进行近似分析。然后 ,用数值方法考核了近似分析结果的可靠性 ,讨论了流体速度、绳索质量、重力和初始状态等对绳索运动行为的影响。 相似文献
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水介质对多种边界条件方板振动频率及辐射效率的影响 总被引:1,自引:2,他引:1
本提出了一种简便计算置于无限大障板上的方板水中振动频率以及辐射效率的计算方法。在假定流体不可压、方板作小振幅振动、水中模态挠度近似为真空模态挠度的条件下,利用瑞利积分得到了因流体压而引起的附加质量密度。进而应用瑞利方法得到了方板水中振动频率与真空中振动频率、无量纲附加虚质量增量之间的关系。在真空中模态的有限元方法分析数据以及采用适当方法处理奇点积分的基础上,应用离散积分计算了无量纲附加虚质量增量的值。从真空中模态特征频率出发用迭代法直到水中频率收敛为止而得到水中方板的特征频率,进而计算了方板的模态辐射效率。方法的有效性通过方板的无量纲附加虚质量增量与献[11]结果对比的一致性来验证。 相似文献
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子波分析在声辐射和声散射中的应用 总被引:1,自引:0,他引:1
文章提出将子波分析用于求解声学中的边界积分方程,能提高现有边界元方法解决工程问题的能力。在子波分析于声辐射和声散射的应用研究中,提出了把积分核函数用级数展开,建立频率响应函数计算的频率迭代技术,大大提高了频率响应函数的计算效率。讨论了子波分析在声学工程数值计算中的研究前景。 相似文献
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结构动特性灵敏度分析的边界元摄动法 总被引:2,自引:0,他引:2
本文对离散后的边界积分方程采用摄动理论,把求结构特征解灵敏度的偏导数公式改写成摄动公式,导出了用边界元法计算结构动特性灵敏度的一种新方法。文中给出了边界元摄动法灵敏度分析的公式,数值实施过程和数值结果。算例表明,本文方法是正确的,且有良好的精度。 相似文献
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Z. Zong 《Acta Mechanica》2003,161(3-4):179-194
Summary. The dynamic plastic response of a submerged free-free beam to an underwater explosion bubble is studied in this paper. A
fluid-structure analysis is given to find the fluid force acting on the beam. Assuming that the beam is made from rigid, perfectly
plastic material, we obtain the hydroplastic equation governing the dynamic plastic deflection of such a beam. The equation
is analytically solved. Examples are given to discuss the features of the dynamic plastic response. It is observed that longer
beams sustain larger plastic deformations than shorter beams, but shorter beams undergo larger rigid body motion than longer
beams. Most of energy is consumed on plastic deformation rather than on rigid body motion. It is impossible, however, for
more than three hinges to form on the beam.
Received May 23, 2002; revised October 22, 2002
Published online: April 17, 2003 相似文献
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Coupled FE–BE method for eigenvalue analysis of elastic structures submerged in an infinite fluid domain 下载免费PDF全文
C. J. Zheng C. Zhang C. X. Bi H. F. Gao L. Du H. B. Chen 《International journal for numerical methods in engineering》2017,110(2):163-185
For thin elastic structures submerged in heavy fluid, e.g., water, a strong interaction between the structural domain and the fluid domain occurs and significantly alters the eigenfrequencies. Therefore, the eigenanalysis of the fluid–structure interaction system is necessary. In this paper, a coupled finite element and boundary element (FE–BE) method is developed for the numerical eigenanalysis of the fluid–structure interaction problems. The structure is modeled by the finite element method. The compressibility of the fluid is taken into consideration, and hence the Helmholtz equation is employed as the governing equation and solved by the boundary element method (BEM). The resulting nonlinear eigenvalue problem is converted into a small linear one by applying a contour integral method. Adequate modifications are suggested to improve the efficiency of the contour integral method and avoid missing the eigenvalues of interest. The Burton–Miller formulation is applied to tackle the fictitious eigenfrequency problem of the BEM, and the optimal choice of its coupling parameter is investigated for the coupled FE–BE method. Numerical examples are given and discussed to demonstrate the effectiveness and accuracy of the developed FE–BE method. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Timoshenko薄壁梁弯扭耦合振动的动态传递矩阵法 总被引:1,自引:1,他引:0
通过直接求解单对称均匀Timoshenko薄壁梁单元弯扭耦合振动的运动偏微分方程,导出了其自由振动时的动态传递矩阵,同时采用结合频率扫描法的二分法求解频率特征方程,并讨论了剪切变形和转动惯量对弯扭耦合Timoshenko薄壁梁的固有频率的影响.数值结果验证了本文方法在其适用范围内的精确性和有效性. 相似文献
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《Engineering Analysis with Boundary Elements》1999,23(9):745-755
This paper presents the solution for a fixed cylindrical irregular cavity of infinite length submerged in a homogeneous fluid medium, and subjected to dilatational point sources placed at some point in the fluid. The solution is first computed for a wide range of frequencies and wavenumbers, which are then used to obtain time-series by means of (fast) inverse Fourier transforms into space–time.The method and the expressions presented are implemented and validated by applying them to a fixed cylindrical circular cavity submerged in an infinite homogeneous fluid medium subjected to a point pressure source for which the solution is calculated in closed form.The boundary elements method is then used to evaluate the wave-field elicited by a point pressure source in the presence of fixed rigid cylindrical cavities, with different cross-sections, submerged in an unbounded fluid medium and in a half-space. Simulation analyses with this idealized model are then used to study the patterns of wave propagation in the vicinity of these inclusions. The amplitude of the wavefield in the frequency vs axial-wavenumber domain is presented, allowing the recognition, identification, and physical interpretation of the variation of the wavefield. 相似文献
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竖向地震荷载下输液管道弯曲振动的有限元分析 总被引:13,自引:1,他引:12
将与固定构筑物连接处的管道视为弹性梁,并考虑管道基础的不均匀沉降竖向地震荷载的作用及管内液体流动引起的耦联振动,建立数学模型,进行动力响应分析,针对某些介质和结构参数,给出了一些数值结果,得出了流速对管道动力响应管道动力响应影响及管端不均匀沉降对其动力响应影响的若干初步结论。 相似文献
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附加减震装置的一维杆或剪切梁模型属于非连续的非经典阻尼分布参数系统.对于它的动力分析,通常是建立分段的运动方程,然后利用各段动力反应的实振型叠加形式和连续条件进行动力计算.这是一种实模态综合方法,尽管它可以求得近似的动力反应,但反映不出阻尼对整体系统动力特性的影响.为了考虑附加减震装置引起的阻尼和刚度非连续性,基于广义... 相似文献
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基于线性PTT本构模型对非等温粘弹流体4∶1平板收缩流进行了模拟,其中分子松弛时间、聚合物黏度与温度的依赖关系通过WLF公式描述。控制方程采用同位网格有限体积法求解,速度-压力以及速度-应力间的耦合采用动量插值技术处理。文中给出了不同We数下粘弹流体等温和非等温情况下流场和应力场的变化情况,分析了温度对流场和应力场的影响,考察了Pe数、We数以及能量方程中参数k对温度场的影响。 相似文献
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This paper investigates the free vibrations of a cantilever micro-beam submerged in a bounded frictionless and incompressible fluid cavity. Based on the Fourier–Bessel series expansion and using linear potential theory, an analytical method is proposed to analyze the eigenvalue problem, where the fluid effect emerges as an added mass. Wet beam vibration mode shapes together with the sloshing modes of the oscillating liquid are depicted. Moreover, effects of geometrical configuration and fluid density on the natural frequencies of the coupled system are evaluated. Results show that in spite of the high added mass values related to lower modes, presence of the fluid changes the higher modes more effectively. 相似文献