共查询到19条相似文献,搜索用时 281 毫秒
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粘弹性边界梁在低速冲击下的动力响应分析 总被引:1,自引:1,他引:0
实际工程中的梁结构通常具有粘弹性边界,这些约束表现为弹性和阻尼特征.建立了具有粘弹性边界梁的力学模型,该模型综合考虑弹性和阻尼支承、集中质量块以及支承不对称等情况,根据冲击局部区域的接触力-侵入深度关系式并利用拉格朗日方法建立了横向冲击下粘弹性边界梁的动力方程,并通过与简支梁在相同冲击条件下冲击力和横向位移的对比分析,说明了粘弹性支承对结构动力响应的影响.研究表明,粘弹性边界梁的横向位移比简支梁要小,而且位移到达峰值时的时间有所增加,从而提高结构的抗力. 相似文献
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从三维粘弹性本构关系出发,导出了具有多个点弹性支承的Kelvin型粘弹性矩形薄板的运动微分方程。针对方程中出现的二维广义d函数,采用积分方程法导出了具有多个点弹性支承的四边简支Kelvin型粘弹性矩形薄板自由振动的复特征方程,分析了材料的无量纲延滞时间、点弹性支承的弹性系数和支承位置对矩形薄板的固有频率的影响。 相似文献
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阻尼材料对环肋柱壳稳态响应影响的分析 总被引:1,自引:0,他引:1
利用Flugge壳体理论,讨论了敷设自由层粘弹性阻尼材料的环肋柱壳受周期性径向激励的稳态响应,用复模量形式计及基壳和粘弹性阻尼材料的损耗因子,并计入流固耦合作用,讨论了粘弹性阻尼材料的物理参数和厚度对其稳态响应的影响。 相似文献
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本文研究了具有纵向干摩擦支承的矩形板和梁的非线性强迫振动,文中采用双线性迟滞弹簧摩擦模型表示边界摩擦力,按照该模型,随位移幅值增加,板和梁的摩擦面相继经历粘住,瞬态滑动,粘住-滑动三种运动状态,由Galerkin法和一阶HBM法求板和梁的稳态响应,通过对摩擦力参数变化时的典型幅频曲线的数值仿真,揭示在软,硬弹簧非线性的综合影响下,系统的振动性态及其摩擦阻尼的作用机理,此外,文中还导出边界干摩擦力的 相似文献
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基于Euler-Bernoulli梁理论,分析了具有粘弹性支座的钢筋混凝土梁在低速冲击作用下的弹性动力响应问题。根据准静态Hertz接触理论和梁的横向振动方程,建立了梁在弹性阶段的动力响应方程组,给出了梁动力函数和支座动力函数的计算方法。研究表明:粘弹性支座使梁的位移峰值减小,而且位移到达峰值的时间也有所延后,有利于提高梁结构的抗冲击能力。与刚性支承相比,粘弹性支座的附加惯性力降低了梁动力函数和支座动力函数值,并降低了梁的振动频率;梁动力函数和支座动力函数值随支座阻尼增大而减小,且支座阻尼加速了动力函数值衰减;除了采用粘弹性支座外,缩短冲击荷载的作用时间也可以减小结构的动力响应。 相似文献
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Zijie Fan 《International journal for numerical methods in engineering》2001,51(5):619-630
This work considers transient vibration and sound radiation from an impact‐excited rectangular plate with viscoelastic boundary supports. The approach used is based on the modal strain energy (MSE) method. Vibration of the plate is approximated by a double infinite series in the spatial co‐ordinates. Each term of the series is constructed with vibration modes of beams having the same boundary conditions as the plate, multiplied by a time‐dependent function. Modal loss factor of each mode is obtained by the MSE method. The sound radiation pressure in the time and frequency domain is obtained by numerical integration of the Rayleigh integral. Effects of the viscoelastic boundary supports on the vibration response and the radiated sound pressure of the vibrating plate are also discussed. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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建立了带压电分流阻尼系统的四边固支正方形弹性薄板振动控制的实验模型。针对其前五阶模态振动响应的抑制问题,以压电元件存储的电能最大化为优化目标,对采用多个压电元件的压电分流阻尼系统进行了布局优化分析。将压电元件布局优化后的压电分流阻尼系统应用于弹性薄板的多阶模态振动响应的抑制实验,分别研究了不同压电元件数量和布局对抑振效果的影响。在压电分流阻尼抑振实验中,与分流电路开路时相比,电路闭路后弹性薄板的频响函数在对应的模态频率处的幅值分别降低了11.90dB、16.94dB、16.94dB、19.91dB和16.77dB,说明经过布局优化后的压电分流阻尼系统使弹性薄板的前五阶稳态响应都得到了很好的抑制。同时也进行了非优化布局的压电分流阻尼抑振实验,实验结果对比表明,对压电元件进行布局优化可以明显提高压电分流阻尼系统的抑振效果。 相似文献
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共固化粘弹性复合材料兼具结构承载和阻尼减振功能。针对传统的混合单元法在应用于粘弹性夹层复合材料结构阻尼性能分析时存在着前处理困难、计算规模大、精度低以及难以考虑正交各向异性铺层自身损耗能力的缺点,推导了一种基于Layerwise离散层理论的四节点四边形复合材料层合板单元,并利用直接复特征值解法建立了共固化粘弹性复合材料结构的阻尼性能分析方法。将该方法应用于不同的阻尼结构,分析结果与文献中已公开结果和混合单元法的计算结果进行了对比验证。结果表明,基于离散层理论的层合板单元具有计算精度高、前处理建模简单和计算规模小的优点,可有效应用于复杂共固化粘弹性复合材料结构的阻尼性能分析和设计。 相似文献
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V. G. Karnaukhov I. F. Kirichok M. V. Karnaukhov 《Journal of Engineering Mathematics》2008,61(2-4):399-411
A mathematical formulation of a new nonlinear problem for active vibration damping (ACD) of thin viscoelastic plates by distributed piezoelectric sensors and actuators is given. The influence of dissipative heating on ACD is considered. The nonlinearity of the problem is caused by the temperature dependence of the material properties and the nonlinearity of the dissipative function. The thermomechanical behavior of the materials under harmonic loading is described by the concept of complex characteristics. Numerical and analytical methods are used for solving this problem. As an example, the influence of dissipative heating on damped axisymmetric bending vibrations of a circular viscoelastic plate is investigated. It is shown that this influence can be significant in the case of ACD of polymeric plates. 相似文献
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对一般线性粘弹性阻尼器(含线性橡胶隔震支座)耗能结构的非正交振型叠加精确解法进行了系统研究。首先采用最一般的线性粘弹性阻尼器的积分型精确分析模型,用微分积分方程组实现一般粘弹性阻尼器耗能结构的时域非扩阶精确建模;然后采用传递矩阵法,直接在耗能结构原始空间上获得了一般线性粘弹性耗能变频结构在任意激励和非零初始条件下位移与速度时域瞬态响应的非正交振型叠加精确解;通过与3种典型结构的对比分析,验证了该精确解的正确性、简易性和普适性。该非扩阶精确解具有明确的物理意义,可视为现有比例粘滞阻尼定常结构的经典正交振型叠加精确解在一般线性粘弹性阻尼耗能变频结构的推广,能从本质上精确揭示耗能结构的振动机理,即尽管耗能结构的振型不具有正交性,但耗能结构响应仍然可精确分解为各振型响应的线性组合。此振动机理将为建立耗能结构精确的振型分解反应谱法提供分析路径,同时可将现有用于一般粘滞阻尼定常结构的参数识别、动力修改、最优控制及优化设计等方法推广到一般粘弹性阻尼变频非定常结构。 相似文献
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Employing a method of vibration testing due to Kennedy and Pancu, with elementary extensions, forced damped modes of vibration of unit fabricated structures have been studied. Theoretical and practical procedures associated with the tests are discussed and the response vector diagrams and mode shape diagrams presented for the third bending mode of vibration of single and combined unit structures. The existence and accuracy of damped modes of vibration are discussed. Test results indicate that by applying this vibration testing method, approximate forced damped modes of vibration of unit structures are uncovered. The dynamic characteristics of these modes will be suitable for use in design and development studies. 相似文献
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提出了敷设粘弹性阻尼层的复合材料层合结构随机振动分析的高效精确算法。考虑了粘弹性阻尼材料对激振频率的依赖性及Adams 提出的复合材料层合结构的阻尼模型。为解决依赖频率变化的非经典阻尼的复杂结构, 结合实模态降阶直接解法对虚拟激励法做了相应的发展, 精确求解了降阶后的随机振动方程。以国产有限元程序系统DDJ 为平台开发了相应的程序,并对波音737 客机的水平尾翼的复合材料安定面结构进行模拟研究,从复杂的计算及合理的结论可以看出, 本文中所提出的方法对复合材料的随机振动分析十分有效。 相似文献
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Y. Xiang Y. B. Zhao G. W. Wei 《International journal for numerical methods in engineering》2002,55(8):947-971
Part 2 of this series of two papers presents the applications of the discrete singular convolution (DSC) algorithm. The main purpose of this paper is to explore the utility, test the accuracy and examine the convergence of the proposed approach for the vibration analysis of rectangular plates with internal supports. Both partial internal line supports and complex internal supports are considered for 21 square plates of various combinations of edge support conditions. The effects of different size, shape and topology of the internal supports and different boundary conditions on the vibration response of plates are investigated. The partial internal line supports may vary from a central point support to a full range of cross or diagonal line supports. Several closed‐loop supports, such as ring, square and rhombus, and their combinations are studied for complex internal supports. Convergence and comparison studies are carried out to establish the correctness and accuracy of the DSC algorithm. The DSC results are compared with those in the available literature obtained by using other methods. Numerical results indicate that the DSC algorithm exhibits controllable accuracy for plate analysis and shows excellent flexibility in handling complex geometries, boundary conditions and support conditions. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献