共查询到19条相似文献,搜索用时 156 毫秒
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采用有限元法,建立约束阻尼板的动力学模型;结合瑞利积分方程推导板结构的振动辐射声功率。建立以辐射声功率最小化为目标函数,以约束阻尼材料布置位置和厚度为设计变量的约束阻尼结构声辐射优化模型。提出基于渐进优化算法(ESO)和遗传算法(GA)的约束层阻尼板振动声辐射的分层优化设计策略,获得约束阻尼材料的位置和厚度优化配置。结果表明:在保持附加质量不变的条件下,以约束阻尼材料布置位置最优的约束阻尼板为初始结构,对各区域约束阻尼材料的厚度重新配置,能够获得更好的结构振动辐射声功率的控制效果。 相似文献
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根据经典薄板理论,建立约束阻尼板有限元模型,将其视作镶嵌于无限大刚性障板,利用Rayleigh积分法推导结构的辐射声功率及灵敏度表达式。以一阶峰值频率或频带激励下的声功率最小化为目标,约束阻尼材料体积分数为约束条件,建立拓扑优化模型,采用渐进优化算法,编制了优化计算程序,获得了约束阻尼材料的最优拓扑构型,并与全覆盖板及基板的辐射声功率进行了对比。研究表明:以声功率最小化为目标,对约束阻尼材料布局进行拓扑优化,能有效抑制结构的振动声辐射,为结构低噪声设计提供了重要的理论参考和技术手段。 相似文献
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频率相关自由阻尼层复合材料加筋板动力分析 总被引:1,自引:0,他引:1
采用子空间迭代法和精细积分对敷设粘弹性阻尼层的含损伤复合材料加筋板结构进行了频率和动力响应分析。分析中对层合板和层合梁采用了Adams应变能法与Raleigh阻尼模型相结合的阻尼矩阵构造方法;对表面粘弹性阻尼材料则考虑了材料性质和耗散系数对激振频率与温度的依赖性,建立了频率相关粘弹性材料阻尼矩阵的计算方法。通过有限元分析,分别研究了敷设自由阻尼层无损伤和含分层损伤复合材料加筋板的自振频率和模态特征,并根据幅频曲线讨论了阻尼材料模量、耗散系数和阻尼层厚度等因素对结构响应的影响,提出的计算方法对通过合理选择阻尼层材料与几何参数来有效地控制加筋板结构的振动特性,具有一定的参考价值。 相似文献
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Loss behavior of viscoelastic sandwich structures: A statistical-continuum multi-scale approach 总被引:1,自引:0,他引:1
Yao KoutsawaWiyao Leleng Azoti Salim Belouettar Rodolphe MartinEvgeny Barkanov 《Composite Structures》2012,94(4):1391-1397
This work presents a multi-scale model of viscoelastic constrained layer damping treatments for vibrating plates/beams. The approach integrates a finite element (FE) model of macro-scale vibrations and a statistical-continuum homogenization model to include effects of micro-scale structure and properties. The statistical-continuum homogenization model makes the micro- to macro-scale transition to approximate the effective behavior of the heterogeneous core by using n-point probability functions. A simple sound transmission model is used to show the effect of material microstructure on the sound transmission loss of the sandwich structure. The damping behavior resulting from the presence of voids and negative stiffness regions in the core material is modeled. This study clearly shows that, it is of high interest to research either material structures or processing techniques which lead to negative stiffness behavior. The results also poignantly show that the proposed multi-scale model yields insight on heterogeneous material behavior leading to increased damping properties and ultimately enhances the ability to design sandwich beam/plates. 相似文献
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Yao Koutsawa Michael R. Haberman El Mostafa Daya Mohammed Cherkaoui 《International Journal of Mechanics and Materials in Design》2009,5(1):29-44
This work presents a multiscale model of viscoelastic constrained layer damping treatments for vibrating plates/beams. The
approach integrates a finite element (FE) model of macroscale vibrations and a micromechanical model to include effects of
microscale structure and properties. The FE model captures the shear deformation of the viscoelastic core, rotary inertial
effects of all layers, and viscoelastic boundaries of the plate. Comparison with analytical and FE results validates the proposed
FE model. A self-consistent (SC) model makes the micro to macro scale transition to approximate the effective behavior a heterogeneous
core. Modal damping resulting from the presence of voids and negative stiffness regions in the core material is modeled. Results
show that negative stiffness regions in the viscoelastic core material, even at low volume fractions, yield superior macroscopic
damping behavior. The coupled SC and FE models provide a powerful multiscale predictive design tool for sandwich beams and
plates. 相似文献
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M. A. Trindade A. Benjeddou R. Ohayon 《International journal for numerical methods in engineering》2001,51(7):855-864
An electromechanically coupled finite element model has been presented in Part 1 of this paper in order to handle active–passive damped multilayer sandwich beams, consisting of a viscoelastic core sandwiched between layered piezoelectric faces. Its validation is achieved, in the present part, through modal analysis comparisons with numerical and experimental results found in the literature. After its validation, the new finite element is applied to the constrained optimal control of a sandwich cantilever beam with viscoelastic core through a pair of attached piezoelectric actuators. The hybrid damping performance of this five‐layer configuration is studied under viscoelastic layer thickness and actuator length variations. It is shown that hybrid active–passive damping allows to increase damping of some selected modes while preventing instability of uncontrolled ones and that modal damping distribution can be optimized by proper choice of the viscoelastic material thickness. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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The free vibration and damping characteristics of plates consisting of composite stiff-layers and an isotropic viscoelastic core were studied under thermal loads using finite element method. The temperature dependence of viscoelastic core properties and effects of pre-stresses are taken into account. The inherent composite damping and damping due to viscoelastic layer are compared. Parametric study is conducted with fiber angle, ply lay-up, and core thickness as parameters. The results show some interesting phenomenon like shifting of modes with temperature. 相似文献
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Hybrid damping designs with active piezoelectric materials and passive viscoelastic materials (VEMs) combine the advantages of both active and passive constrained layer damping (ACLD/PCLD) treatments.Researchers have established the standards for the extent and placement of the PCLD treatment for common structures. However for ACLD treatment, such detailed studies are not available. This study is aimed to examine, the effect of parametric variation of active constrained layer on the vibration control of the beams treated with optimally placed active or passive constrained layer damping patches. Finite element model is developed to model the open-loop and close-loop dynamics of active/passive constrained layer damping treated beam. The placement strategies of ACLD patches are devised using the modal strain energy (MSE) approach. Extensive experimentation studies are conducted by making twenty one separate samples of ACLD/PCLD treated beams with variations in viscoelastic material layer thickness, ACLD/PCLD patch coverage and location of the patch. Effects of key parameters, such as control gain, viscoelastic material thickness, coverage and location variation of ACLD patch on the system loss factor have been investigated. The careful analysis of results from partially covered ACLD treated beam suggests that the maximum damping of the first mode can be achieved by attaching the ACLD patch only up to 50% coverage. It also reveals that with proper choice of the control voltage and thickness, the effective loss factor can be almost doubled. The present study suggests the potential use of parametric studies that establish some guide lines for the extent and placement of the ACLD patches on the cantilevered beam. 相似文献
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S. R. Sahoo M. C. Ray 《International Journal of Mechanics and Materials in Design》2018,14(3):359-374
This paper is concerned with the development of mesh free model for the performance analysis of active constrained layered damping (ACLD) treatments on smart laminated composite beams. The overall structure is composed of a substrate laminated composite beam integrated with a viscoelastic layer and a piezoelectric layer attached partially or fully at the top surface of the substrate beam. The piezoelectric layer acts as the active constraining layer of the smart beam and the viscoelastic layer acts as the constrained layer. A layer wise displacement theory has been used to derive the models. Both symmetric cross-ply and antisymmetric angle-ply laminated beams are considered for the numerical analysis. It is observed that ACLD treatment significantly improves the active damping properties of the substrate beam. The numerical results also reveal that the triangular ACLD treatment is more effective than the rectangular ACLD treatment of same thickness and volume for active damping of smart composite beams. 相似文献
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计算粘弹结构动力学参数的新模态应变能方法 总被引:1,自引:0,他引:1
粘弹结构在噪声与振动控制领域已得到广泛应用,然而准确地计算粘弹结构的动力学参数一直存在困难,模态应变能法及其修正方法常用作近似计算。在分析模态应变能方法和已有修正方法的原理及其相互关系的基础上,提出一种基于损耗因子幅值的新模态应变能方法,用于计算粘弹结构的损耗因子与固有频率。新方法的修正因子随粘弹结构对应模态阶次损耗因子幅值变化。取可等价为粘弹性夹层梁/板的四参数原型系统和新型高阻尼航天载荷隔振器为算例,通过与已有方法的对比分析了新方法的准确性。 相似文献