共查询到19条相似文献,搜索用时 158 毫秒
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研究不同位置四点支承条件下矩形薄板的自由振动特性.首先,在板结构模型的不同位置上引入横向约束弹簧,并设定人工弹簧的刚度值以模拟出四点支承的边界条件.然后,基于二维改进傅里叶级数表示结构的位移容许函数,其中改进部分的正弦附加项可解决以往位移函数在边界上可能存在的求导不连续问题.建立矩形板系统能量对应的泛函,令其取驻值建立线性方程组.最后,求解矩阵特征值问题得到点支承矩形板自由振动频率等参数,给出不同位置四点支承条件下矩形薄板的振动特性.所应用二维改进傅里叶级数法中,位移函数基于改进傅里叶级数展开时的附加项能够提高结果的精度和收敛速度.研究结果为不同位置点支承矩形板的自由振动问题提供一定的参考. 相似文献
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石墨烯是一种新型的碳纳米材料,将石墨烯添加到不同基体中可达到增强基体力学性能,并优化结构的效果.本文主要研究了在悬臂边界条件下石墨烯复合材料板的非线性动力学行为,通过Halpin-Tsai模型计算了复合材料板的等效杨氏模量,运用一阶剪切板理论和Hamilton原理得到复合材料板的非线性动力学方程.通过模态缩聚,得到复合材料板横向位移的运动控制方程.应用Rayleigh-Ritz法计算出复合材料板的固有频率,发现第二阶与第四阶固有频率间存在1:3的关系.利用多尺度法研究了复合材料板在1:3内共振情况下的非线性振动响应,通过数值模拟分析了外激励对板结构非线性振动响应的影响.结果表明:横向外激励对复合材料板的非线性动力学行为影响较大,对实际工程具有一定的指导意义. 相似文献
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李亚魁 《自动化与仪器仪表》1994,(4):14-16
1 概述 随着科学技术的飞速发展,自动化技术也不断提高。但是,在现代化工业生产过程控制和检测系统中,仍离不开节流式标准孔板,尤其是对能源控制,更少不了标准孔板,而且对其要求,更加精确可靠。然而,标准孔板结构上的弱点,是众所周知的。它无法在较长时间里保持高的精确性和可靠性。因此,促使人们不断探索新型孔板结构及其计算和应用的方法。目前,对此种孔板的工业 相似文献
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折叠翼是可变体飞行器设计最有前景的方案之一.在折叠变形过程中,飞行器的气动特性以及振动特性将会发生变化.为了研究折叠翼可变体飞行器机翼的振动特性,本文设计制作了折叠板结构,介绍了建立复杂结构力学模型的方法,用力学实验得到用于离散折叠板结构的低阶模态,并且考察了系统可能存在的内共振频率. 相似文献
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双参数弹性地基上板的自由振动 总被引:3,自引:2,他引:1
建立了双参数弹性地基上的正交异性矩形薄板自由振动位移函数微分方程,并得到其一般解.这可用以精确地求解板在任意边界条件下的自由振动问题.以四边固定的正方形板为例进行了分析,计算过程简单,便于实际应用.亦适用于求解单参数弹性地基和各向同性板情形。 相似文献
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The free transverse vibration characteristics of rectangular plates, including the effect of transverse shear deformation and rotary inertia, are presented. A method based on the variational procedure in conjunction with the finite difference technique is used to determine the natural frequencies and mode shapes. The convergence characteristics of the present method are studied by varying the thickness parameter and running a comparison with the classical thin plate solutions. The effects of the thickness parameter and taper thickness ratio on the vibration characteristics are studied. The predictions are presented for the simply supported and clamped plates and they are compared with existing solutions based on the thin plate theory. 相似文献
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Quartz is a widely used piezoelectric material and quartz resonators are the primary components in many industrial applications due to the piezoelectric effect. To have a thorough understanding on the vibration characteristics of quartz plates, the experimental measurement of resonant frequencies and mode shapes is indispensable. In this paper, two experimental techniques, amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI) and laser Doppler vibrometer (LDV), which are, respectively, full-field and point-wise displacement measurement methods, are used to obtain the out-of-plane vibration characteristics of AT-Cut quartz in real time. The resonant frequencies and the corresponding vibration mode shapes are successfully obtained at the same time from AF-ESPI method. However, only the resonant frequencies of the out-of-plane vibration modes are determined by the LDV. The cantilever and completely free quartz plates are used in this study and the experimental results are verified by the finite element method (FEM) analysis. The cantilever quartz plates are excited from applying voltage and acoustic waves. Furthermore, three designs of electrode for a quartz plate with free-boundary condition are studied. Excellent agreement between the measured data from the optical method and the numerical results predicted by FEM are found for both resonant frequencies and mode shapes. 相似文献
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目前系列化接骨板在材料节约和应力分散上不合理。为快捷设计出理想的接骨板,利用平均化骨骼模型,提出通过语义参数编辑优化设计接骨板的方法。首先,为系列化接骨板在数量与尺寸上的分布合理,构建了一种带权值的平均化骨骼模型;然后,基于平均化骨骼模型设计出具有通用性的参数化接骨板,便于后期编辑修改与优化;最后,利用有限元分析,用基于二分策略调整厚度参数来优化接骨板,在满足应力条件下使接骨板材料尽可能少。实验结果显示,对三叶型接骨板和股骨远端Ⅲ型接骨板优化后体积分别减小2.7%和12.2%,最大应力分别减小56.9%和24.4%,表明所提方法能够节省接骨板材料,分散接骨板应力,是一种有效的接骨板优化设计方法。 相似文献
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Gerard C. Pardoen 《Computers & Structures》1978,9(1):89-95
The asymmetric vibration and stability of circular and annular plates using the finite element method is discussed. The plate bending model consists of one-dimensional circular and annular ring segments using a Fourier series approach to model the problem asymmetries. Using displacement functions which are the exact solutions of the static plate bending equation, the stiffness coefficients corresponding to the 1st and nth harmonics are used in closed form. By assuming that the static displacement function closely represents the vibration and stability modes, the mass and stability coefficient matrices for an annular and circular element are also constructed for the 1st and nth harmonics. Several numerical examples are presented to demonstrate the efficiency and accuracy of the finite element model with that of classical methods. 相似文献
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Anders A. Larsen Bogi Laksafoss Jakob S. Jensen Ole Sigmund 《Structural and Multidisciplinary Optimization》2009,37(6):585-594
We propose a topological material layout method to design elastic plates with optimized properties for vibration suppression
and guided transport of vibration energy. The gradient-based optimization algorithm is based on a finite element model of
the plate vibrations obtained using the Mindlin plate theory coupled with analytical sensitivity analysis using the adjoint
method and an iterative design update procedure based on a mathematical programming tool. We demonstrate the capability of
the method by designing bi-material plates that, when subjected to harmonic excitation, either effectively suppress the overall
vibration level or alternatively transport energy in predefined paths in the plates, including the realization of a ring wave
device.
Most of this work was performed while AAL was employed at the Department of Mechanical Engineering. 相似文献
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《Computers & Structures》2007,85(11-14):1089-1096
A fluidelastic model has been developed for studying the dynamics of cantilevered plates in axial flow, with an additional spring support at the plate trailing edge. The plate is supposed to be two-dimensional; a nonlinear equation of motion based on the inextensibility condition is used to account for the possible large vibration amplitude. For the fluid-dynamic part, an unsteady lumped vortex model is used for calculating the fluid loads acting on the plate undergoing deformation; the longitudinal displacement of the plate associated with lateral motions is also taken into account. The fluidelastic model is first validated through comparisons with experimental data published for systems without the spring support; it is then used to investigate the dynamics of cantilevered plates in axial flow with an additional spring support at the plate trailing edge. Some interesting results of the dynamics of the fluid–structure system are presented. 相似文献
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对作大范围运动功能梯度材料矩形薄板的刚柔耦合动力学问题进行了研究.以连续介质力学为基础,在柔性薄板面内变形中考虑了传统建模方法忽略的二次耦合变形量,采用假设模态法对薄板变形位移进行离散,运用拉格朗日方程推导了大范围运动功能梯度材料板的刚柔耦合动力学方程.对旋转运动下取不同功能梯度指数的悬臂功能梯度板的动力学行为进行仿真,比较了本文建立的一次近似耦合模型和传统不计耦合变形项的零次近似模型.结果表明,随着转速的提高,传统零次模型发散,而本文模型收敛,能够较好地描述系统动力学行为.利用本文建立的一次近似模型,研究了功能梯度指数对转动功能梯度板变形的影响,研究表明,随着功能梯度指数的增大,板的横向变形也增大.通过求解旋转FGM板在恒定转速下的固有频率,进一步分析了功能梯度板材料组分变化对板振动特性的影响. 相似文献
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Dynamic stiffness elements for plates are developed using first order shear deformation theory to carry out exact free vibration analysis of plate assemblies. The analysis has been facilitated by the application of Hamiltonian mechanics and symbolic computation. The Wittrick–Williams algorithm has been used as the solution technique. Results have been extensively validated using published literature for both uniform and non-uniform plates. Some finite element results are also provided. The accuracy and computational efficiency of the method are demonstrated. In the final part of the investigation, significant plate parameters are varied and their subsequent effects on the free vibration characteristics are studied. 相似文献