Mechanics Research Communications最新文献_第10页

Effect of shape and interpenetration of ellipsoidal pores on effective physical properties of closed-cell porous materials 椭圆孔的形状和相互渗透对闭孔多孔材料有效物性的影响

IF 2.3 4区工程技术 Q3 MECHANICS

Mechanics Research Communications

Pub Date : 2025-09-24 DOI: 10.1016/j.mechrescom.2025.104527

Hiroyuki Ono , Masaki Kobayashi , Hirokazu Matsuura

The purpose of this study is to clarify the effects of pore shape and interpenetration on the effective elastic modulus and thermal conductivity of closed-cell porous materials. For this purpose, the theoretical solutions for these effective physical properties of a model with ellipsoidal pores oriented randomly in the matrix are derived based on some homogenization methods such as the differential scheme (DS). The obtained solutions are expressed uniformly in terms of the geometrical factors given only by the aspect ratio of ellipsoidal pores. In addition, a model in which ellipsoidal pores are not only oriented randomly in the material but also interpenetrating is generated using the regular polyhedron orientation method associated with the golden ratio. Finite element method (FEM) analyses of this model are also performed. The effective physical properties of various closed-cell porous materials are calculated by the theoretical solutions and FEM. These results are compared with the experimental ones. When spherical pores do not interpenetrate, the DS results for effective physical properties show good agreement with the experimental and FEM results. However, when spherical pores interpenetrate, the DS results tend to be slightly higher than these results. This difference becomes negligible when the pore volume fraction is less than 0.5. Moreover, when the pore shape is non-spherical, such as elongated or flattened, the effect of interpenetration is reduced. As a result, the DS results show good quantitative agreement with the FEM results. These findings demonstrate that the DS can evaluate the effective physical properties of porous materials with a certain degree of accuracy, regardless of the shape and interpenetration of pores. The effective Young’s modulus and thermal conductivity tend to be highest when the pore shape is spherical and decrease as the pore shape becomes flatter. As an application of these findings, we present design guidelines for hybrid porous materials that improve insulation while maintaining stiffness.

本研究的目的是阐明孔隙形状和相互渗透对闭孔多孔材料有效弹性模量和导热系数的影响。为此，基于微分格式（DS）等均质化方法，推导了椭球状孔隙在基体中随机取向模型的这些有效物理性质的理论解。所得的解统一地表示为仅由椭球孔长径比给出的几何因子。此外，利用黄金分割的正多面体定向方法，生成了椭球状孔隙在材料中随机定向且相互贯通的模型。并对该模型进行了有限元分析。采用理论解和有限元方法计算了各种闭孔多孔材料的有效物理性能。所得结果与实验结果进行了比较。当球形孔隙不互渗时，有效物性的DS计算结果与实验和有限元计算结果吻合较好。然而，当球形孔隙相互渗透时，DS结果往往略高于这些结果。当孔隙体积分数小于0.5时，这种差异可以忽略不计。此外，当孔隙形状为非球形时，如拉长或扁平时，相互渗透的影响减弱。结果表明，数值模拟结果与有限元计算结果吻合较好。这些结果表明，在不考虑孔隙形状和相互渗透的情况下，DS能够以一定的精度评价多孔材料的有效物理性质。孔隙形状为球形时，有效杨氏模量和导热系数最高，孔隙形状越扁平，有效杨氏模量和导热系数越低。作为这些发现的应用，我们提出了混合多孔材料的设计指南，以提高绝缘，同时保持刚度。

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引用次数: 0

Recent developments in the modeling of thin-walled structures combining GBT and shell finite elements GBT与壳单元结合薄壁结构建模的最新进展

IF 2.3 4区工程技术 Q3 MECHANICS

Mechanics Research Communications

Pub Date : 2025-09-17 DOI: 10.1016/j.mechrescom.2025.104525

Rodrigo Gonçalves , Dinar Camotim , David Manta

This paper presents a state-of-the art report on recent developments concerning the modeling of thin-walled members and frames, by combining the advantages of Generalized Beam Theory (GBT) and conventional shell finite elements. Two approaches are reported. The first one combines, in the same model, GBT-based (beam) and shell finite elements, through appropriate constraint equations. The beam elements are employed only in the elastic and prismatic zones, since the remaining zones are handled more efficiently with shell elements. The second approach recovers the insightful GBT mode participations from shell finite element results, through post-processing operations. This approach is useful when GBT elements are not available, cannot be employed (e.g., in tapered members) or are not computationally advantageous, and has a significant potential of application in standard finite element programs, since its implementation is quite straightforward. Throughout the paper, several numerical examples are presented and discussed, to illustrate the application and show the capabilities of the two approaches.

本文结合广义梁理论（GBT）和传统壳有限元的优点，介绍了薄壁构件和框架建模的最新进展。报告了两种方法。第一种是在同一模型中，通过适当的约束方程，将基于gbt的（梁）有限元和壳有限元结合起来。梁单元仅用于弹性和棱柱区域，因为其余区域使用壳单元更有效地处理。第二种方法通过后处理操作从壳有限元结果中恢复有洞察力的GBT模式参与。当GBT单元不可用，不能使用（例如，在锥形构件中）或计算上不有利时，这种方法很有用，并且在标准有限元程序中具有重要的应用潜力，因为它的实现非常简单。在整篇文章中，给出并讨论了几个数值例子，以说明这两种方法的应用和能力。

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引用次数: 0

Energy harvesting from topological interface states in an elastic beam array system 弹性束阵列系统拓扑界面态能量收集

IF 2.3 4区工程技术 Q3 MECHANICS

Mechanics Research Communications

Pub Date : 2025-09-15 DOI: 10.1016/j.mechrescom.2025.104506

Stepa Paunović , Milan Cajić , Danilo Karličić , Mihailo Lazarević , Sondipon Adhikari

Recent discoveries of exotic topological phenomena in mechanical phononics and metamaterials have become a prominent focus in engineering research. These findings not only expanded the functionality and potential applications of such artificial materials and structures but also went well beyond the initial identification of effects such as band gaps. In this study, we propose energy harvesting from localized interface modes in a periodic beam array system. The system is composed of elastically connected parallel beams, with bimorph piezoelectric beams considered at the interface. We derive a system of governing equations, and respective eigenvalue problems for both the full finite lattice model and a reduced-order model based on Bloch mode synthesis are defined and solved. We analyze the topological properties, eigenspectrum, frequency–voltage relationships, and steady-state responses to explore localized interface modes and their energy harvesting capabilities. Additionally, we investigate the robustness of the frequency of topologically protected interface modes in the presence of a mass defect in the lattice, demonstrating the efficiency of the proposed energy harvesting system.

近年来，机械声学和超材料领域的奇异拓扑现象的发现已成为工程研究的一个突出热点。这些发现不仅扩展了这种人造材料和结构的功能和潜在应用，而且远远超出了最初对带隙等效应的识别。在这项研究中，我们提出了在周期波束阵列系统中从局域界面模式收集能量。该系统由弹性连接的平行梁组成，在界面处考虑双晶型压电梁。我们推导了一个控制方程组，定义并求解了基于Bloch模态综合的全有限格模型和降阶模型的特征值问题。我们分析了拓扑特性、特征谱、频率-电压关系和稳态响应，以探索局域界面模式及其能量收集能力。此外，我们研究了在晶格中存在质量缺陷时拓扑保护界面模式频率的鲁棒性，证明了所提出的能量收集系统的效率。

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引用次数: 0

Size effects in hexagonal and Re-entrant metamaterial beams under bending 弯曲作用下六边形和可重入超材料梁的尺寸效应

IF 2.3 4区工程技术 Q3 MECHANICS

Mechanics Research Communications

Pub Date : 2025-09-14 DOI: 10.1016/j.mechrescom.2025.104526

Ahmad Baroutaji

This paper investigates the effects of boundary conditions, cell topology, relative density, and functionally graded pattern on the size effects of metamaterial beams with a hexagonal unit cell subjected to concentrated transverse bending loads. Beams with clamped and simply supported end conditions were studied. Two hexagonal unit cell topologies (regular hexagonal and re-entrant geometries) and two functionally graded approaches (transversally functionally graded and axially functionally graded patterns) are adopted to create various metamaterial beams with different configurations. Numerical finite element analysis (FEA) simulations and the Euler-Bernoulli (EB) beam model were used to estimate the bending responses of the different metamaterial beams.

The results indicate that metamaterial beams with hexagonal unit cells exhibit stiffness-softening size effects under bending. This means that the smaller the difference between the unit cell size and the overall beam size, the larger the apparent deflection of the beam. This size-dependent behaviour of the hexagonal metamaterial beam is well captured by a nonlocal strain-gradient model. The cell topology and functionally graded patterns displayed limited impact on the size effects, while the relative density significantly influenced the size effects. Metamaterial beams with high relative density exhibit weaker size effects than their low relative density counterparts.

本文研究了边界条件、单元拓扑结构、相对密度和功能梯度模式对六边形单元单元梁在集中横向弯曲荷载作用下的尺寸效应的影响。研究了端部夹紧和端部简支的梁。采用两种六边形单元胞拓扑（正六边形和重入几何）和两种功能梯度方法（横向功能梯度和轴向功能梯度模式）来创建不同构型的各种超材料梁。采用数值有限元分析（FEA）和Euler-Bernoulli梁模型对不同超材料梁的弯曲响应进行了估计。结果表明，具有六边形单元胞的超材料梁在弯曲作用下表现出刚度-软化尺寸效应。这意味着单元格尺寸和整体梁尺寸之间的差异越小，梁的表观挠度就越大。非局部应变梯度模型很好地捕捉了六边形超材料梁的这种尺寸依赖性行为。细胞拓扑结构和功能梯度模式对尺寸效应的影响有限，而相对密度对尺寸效应有显著影响。高相对密度的超材料梁比低相对密度的超材料梁表现出更弱的尺寸效应。

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引用次数: 0

Investigation of two-dimensional airfoil ice fracture behavior and influencing factors under aerodynamic loading 气动载荷作用下二维翼型冰断裂行为及影响因素研究

IF 2.3 4区工程技术 Q3 MECHANICS

Mechanics Research Communications

Pub Date : 2025-09-12 DOI: 10.1016/j.mechrescom.2025.104520

Jiaqi Duan , Xianlei Guan , Xian Wang , Xian Yi

Aircraft frequently encounter icing and ice shedding during flight, which poses a serious threat to flight safety. To investigate the fracture and shedding mechanisms of ice accumulation on the wing surface under aerodynamic loads, a numerical model for the fracture and shedding of airfoil ice is established in this paper based on the bond-based peridynamics theory. The aerodynamic load distribution on the outer surface of the ice is obtained using the computational fluid dynamics method and applied as a boundary load to the outer particle layer of the peridynamics model to predict crack initiation and propagation behavior. The ice is formed by the icing of supercooled large water droplets, resulting in a ram’s horn shape. The effects of inflow velocity, angle of attack, ice elastic modulus, and ice critical bond stretch on the fracture behavior of airfoil ice are analyzed. The model effectively predicts the crack initiation time, location, propagation path, and propagation rate. Under low inflow velocity, no cracks were generated; however, as velocity exceeds a critical threshold and the angle of attack increases, cracks are more likely to develop in high-stress regions. Additionally, a lower elastic modulus and fracture toughness significantly accelerate crack formation and propagation. This study provides a theoretical foundation and technical reference for the design of aircraft ice protection systems.

飞机在飞行过程中经常遇到结冰和脱落冰，对飞行安全构成严重威胁。为了研究气动载荷作用下翼面积冰断裂脱落的机理，基于键合周动力理论建立了翼型冰断裂脱落的数值模型。采用计算流体力学方法得到了冰外表面的气动载荷分布，并将其作为边界载荷作用于冰周动力学模型的外颗粒层，以预测裂纹的起裂和扩展行为。冰是由过冷的大水滴结冰形成的，形成了公羊角的形状。分析了入流速度、迎角、冰弹性模量和冰临界粘结拉伸对翼型冰断裂行为的影响。该模型有效地预测了裂纹的起裂时间、位置、扩展路径和扩展速率。低入流速度下，不产生裂缝；然而，当速度超过临界阈值和攻角增大时，高应力区域更容易出现裂缝。此外，较低的弹性模量和断裂韧性显著加速了裂纹的形成和扩展。该研究为飞机防冰系统的设计提供了理论基础和技术参考。

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引用次数: 0

Comparative analysis of beam responses via Hencky and fractional models under different mass distributions 采用Hencky模型和分数阶模型对不同质量分布下的梁响应进行对比分析

IF 2.3 4区工程技术 Q3 MECHANICS

Mechanics Research Communications

Pub Date : 2025-09-11 DOI: 10.1016/j.mechrescom.2025.104511

Soner Aydinlik , Ahmet Kiris , Wojciech Sumelka

This study presents a comparative analysis of the mechanical responses of beams modeled using Hencky and fractional approaches under various mass distribution conditions. The beam models considered in this study are composed of rigid segments connected by rotational springs, with three distinct mass distribution schemes analyzed: masses concentrated at the joints, masses located at the midpoints of each rigid part, and masses uniformly distributed along each segment. The developed model converges to the Euler–Bernoulli beam theory in the continuum limit, as the number of rigid segments tends to infinity. Closed-form expressions for natural frequencies are derived for simply supported boundary conditions. To approximate the dynamic response of these discrete models and capture their scale-dependent effects, corresponding nonlocal fractional continuum models are formulated using the symmetric Caputo derivative. These models enable precise fractional parameter calibration based on discrete systems’ dispersion relations. The analysis reveals a strong influence of the mass distribution on the dynamic behavior, with stiffening or softening effects emerging depending on the mass arrangement. The proposed fractional framework successfully replicates the dispersion characteristics of each discrete Hencky model and confirms that the accurate selection of fractional derivative parameters effectively models the vibrational behavior of microstructured beams.

本文对不同质量分布条件下采用Hencky法和分数法建模的梁的力学响应进行了比较分析。本文所考虑的梁模型由由旋转弹簧连接的刚性段组成，分析了三种不同的质量分布方案：质量集中在节点处，质量位于每个刚性部分的中点，质量沿每个刚性段均匀分布。该模型在连续体极限下收敛于欧拉-伯努利梁理论，刚性段数趋于无穷大。导出了简支边界条件下固有频率的封闭表达式。为了逼近这些离散模型的动态响应并捕捉它们的尺度依赖效应，利用对称Caputo导数建立了相应的非局部分数连续体模型。这些模型能够基于离散系统的色散关系进行精确的分数参数校准。分析表明，质量分布对动态性能有很强的影响，随着质量分布的不同，会出现硬化或软化效应。所提出的分数阶框架成功地复制了每个离散Hencky模型的色散特性，并证实了分数阶导数参数的准确选择有效地模拟了微结构梁的振动行为。

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引用次数: 0

Hygrothermal-induced dynamic behavior of stratified composite plates based on mindlin-reissner analysis 基于mindlin-reissner分析的分层复合材料板湿热致动力行为

IF 2.3 4区工程技术 Q3 MECHANICS

Mechanics Research Communications

Pub Date : 2025-09-07 DOI: 10.1016/j.mechrescom.2025.104519

Saira Javed

This study investigates the vibration analysis of stratified composite plates of constant thickness subjected to hygrothermal effects. The analysis considers the impact of temperature and moisture variations on the material properties and structural response of stratified composite plates. Governing equations are derived using Mindlin-Reissner Theory (MRT) to capture transverse shear effects accurately. The hygrothermal effects are incorporated into the constitutive equations through temperature- and moisture-dependent material properties, leading to a coupled thermo-mechanical model. A numerical approach, such as the spline approximation method, is employed to analyse the frequencies and mode shapes under various edge conditions. The results indicate that increased temperature and moisture content reduce the stiffness of the stratified composite plates, leading to a decrease in natural frequencies. Additionally, the influence of material alignment, assembling sequence, and boundary conditions on the vibrational response is examined. The findings provide critical intuitions into the design and reliability of stratified composite structures exposed to varying environmental conditions, such as in aerospace, marine, and automotive applications.

本文研究了等厚层状复合材料板在湿热作用下的振动分析。分析考虑了温度和湿度变化对层合板材料性能和结构响应的影响。利用Mindlin-Reissner理论（MRT）推导了控制方程，以准确地捕捉横向剪切效应。通过温度和水分相关的材料特性，将湿热效应纳入本构方程，从而形成耦合的热-力学模型。采用样条近似法等数值方法分析了不同边缘条件下的频率和模态振型。结果表明，温度和含水率的升高会降低层状复合材料板的刚度，导致其固有频率降低。此外，还研究了材料排列、装配顺序和边界条件对振动响应的影响。这些发现为暴露在不同环境条件下的分层复合材料结构的设计和可靠性提供了关键的直觉，例如航空航天，船舶和汽车应用。

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引用次数: 0

Non-Fourier heat conduction: Discrete vs continuum approaches 非傅立叶热传导：离散与连续方法

IF 2.3 4区工程技术 Q3 MECHANICS

Mechanics Research Communications

Pub Date : 2025-09-05 DOI: 10.1016/j.mechrescom.2025.104512

S.L. Sobolev

Under far from local-equilibrium conditions, that is on ultra-short space and time scales, the inherent non-locality of the heat conduction process begins to play a crucial role. The discrete variable model (DVM), which assumes that time and space are discrete variables, is one of the most effective approaches to describe the nonlocal effects. Heat conduction equation, energy conservation law, and constitutive equation for the heat flux have been formulated and analyzed in the framework of the DVM. The DVM predicts rather unusual behavior in the spectral characteristics of discrete heat equations on ultrashort time and length scales compared to predictions of continuum approaches. This unusual behavior may serve as a guide for new experimental investigations of high-frequency heat flow regimes, observation of new physical phenomena in solid and thermal materials to expand the range of their technological applications.

To bridge the gap between the discrete and continuum approaches, two invariants for the continualization procedure, namely, thermal diffusivity and propagation velocity of temperature disturbances, have been employed. It has been demonstrated that in the continuum limit the discrete heat equation contains an infinite hierarchy of partial differential equations including classical Fourier, hyperbolic, Guyer-Krumhansl and Jeffreys heat conduction equations. Generalizations of the DVM to two-dimensional and two-temperature cases have been considered. Possible applications of the discrete approach to heat conduction in nano systems and metamaterials have been discussed.

在远离局域平衡的条件下，即在超短的空间和时间尺度上，热传导过程固有的非局域性开始发挥关键作用。离散变量模型（DVM）假设时间和空间是离散变量，是描述非局部效应最有效的方法之一。在DVM的框架下，建立并分析了热传导方程、能量守恒定律和热流本构方程。与连续介质方法的预测相比，DVM在超短时间和长度尺度上预测离散热方程的光谱特征中具有相当不寻常的行为。这种不寻常的行为可以作为高频热流机制的新实验研究的指导，观察固体和热材料中的新物理现象，以扩大其技术应用的范围。为了弥合离散和连续方法之间的差距，连续化过程中使用了两个不变量，即热扩散率和温度扰动的传播速度。在连续介质极限下，离散热方程包含了一个无限层次的偏微分方程，包括经典的傅立叶、双曲、盖耶-克鲁姆汉斯和杰弗里斯热传导方程。将DVM推广到二维和双温度的情况。讨论了离散方法在纳米系统和超材料热传导中的可能应用。

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引用次数: 0

A discrete model for elasticity with microstructure 具有微观结构的离散弹性模型

IF 2.3 4区工程技术 Q3 MECHANICS

Mechanics Research Communications

Pub Date : 2025-09-03 DOI: 10.1016/j.mechrescom.2025.104510

D. Polyzos , T.V. Gortsas , S.V. Tsinopoulos , D.E. Beskos

In the mid-1960s, Mindlin introduced his theory of strain gradient elasticity (SGE), along with one of its most widely recognized simplified versions, known as SGE-Form II. These enhanced theories were motivated by the need to capture dynamic phenomena that classical elasticity fails to address. Although theoretically elegant, the inclusion of numerous material constants and internal length scale parameters makes the practical application of both SGE and SGE-Form II challenging—even for one-dimensional (1D) problems. A practical approach for identifying these parameters involves validating the theories through lattice models, where both the microstructure and macrostructure are materially and geometrically well-defined. Using a simple 1D lattice model with nearest and next-nearest neighbor spring connections and distributed mass, Polyzos and Fotiadis (Int. J. Solids Struct. 49, 470–480, 2012) were the first to successfully validate Mindlin’s SGE-Form II and to interpret the intrinsic parameters introduced by the theory. Despite significant efforts, no lattice model has yet been shown to fully replicate the behavior described by the general SGE theory, even in 1D cases. This gap is addressed in the present work through the use of a simple 1D lattice model and the implementation of a continualization process similar to that employed by Polyzos and Fotiadis (2012).

在20世纪60年代中期，Mindlin介绍了他的应变梯度弹性理论（SGE），以及其最广泛认可的简化版本之一，即SGE- form II。这些强化理论的动机是需要捕捉经典弹性力学无法解决的动态现象。虽然理论上很优雅，但包含大量材料常数和内部长度尺度参数使得SGE和SGE- form II的实际应用具有挑战性-即使是一维（1D）问题。确定这些参数的实用方法包括通过晶格模型验证理论，其中微观结构和宏观结构在材料和几何上都是明确定义的。利用具有最近邻和次近邻弹簧连接和分布质量的简单一维晶格模型，Polyzos和Fotiadis (Int.；J. Solids Struct. 49, 470-480, 2012)首次成功验证了Mindlin的SGE-Form II，并解释了该理论引入的内在参数。尽管付出了巨大的努力，但目前还没有晶格模型能够完全复制一般SGE理论所描述的行为，即使在一维情况下也是如此。在目前的工作中，通过使用简单的一维晶格模型和实现类似于Polyzos和Fotiadis（2012）所采用的连续化过程来解决这一差距。

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引用次数: 0

Nonlinear electromechanical behaviour of piezoelectric thin sheet actuators under large deformation 大变形下压电薄板作动器的非线性机电行为

IF 2.3 4区工程技术 Q3 MECHANICS

Mechanics Research Communications

Pub Date : 2025-09-03 DOI: 10.1016/j.mechrescom.2025.104509

Mostafa Alizadeh, Xiaodong Wang

Piezoelectric thin sheet actuators have diverse potential applications in designing advanced structures, such as programmable systems, tunable active metamaterials and buckling-based energy harvesting systems. In this paper, the nonlinear electromechanical behaviour of piezoelectric thin sheet actuators under large deformation is studied based on a generalized elastica model. The presented model is distinct from the classical elastica, notably by considering the extensibility of the actuator and the coupled electromechanical loads. The thin-sheet actuator is treated as an extensible electroelastic Euler–Bernoulli beam, incorporating piezoelectric effects, axial deformation and large deflection. The problem is formulated as a generalized elastica problem and the analytical solution is provided. The general nonlinear behaviour of the actuator is then evaluated and the existence of different deformation modes is discussed. Typical examples are provided to show the effect of the electromechanical loading condition upon the nonlinear response of the actuator. The results from the new model are also compared with those from a simplified nonlinear model of elastic thin sheets to evaluate the effect of large deformation. The comparison shows a very good agreement for small deformation but predicts a significant discrepancy between the two modes when the deformation is large, indicating the necessity of considering the elastica effect when large deformation is to be considered in design. The current work offers fundamental insights into the electromechanical behaviour of thin-sheet piezoelectric actuators with large deformation, thereby advancing their performance for applications in advanced structures.

压电薄板驱动器在设计先进结构方面具有多种潜在的应用，例如可编程系统、可调谐活性超材料和基于屈曲的能量收集系统。基于广义弹性力学模型，研究了压电薄板作动器在大变形作用下的非线性机电行为。该模型不同于传统的弹性力学模型，特别是考虑了作动器的可扩展性和耦合机电载荷。将薄板作动器视为可扩展的电弹性欧拉-伯努利梁，具有压电效应、轴向变形和大挠度。将该问题表述为广义弹性问题，并给出了解析解。然后评估了执行器的一般非线性行为，并讨论了不同变形模式的存在性。通过典型算例说明了机电加载条件对作动器非线性响应的影响。并将新模型的结果与弹性薄板的简化非线性模型的结果进行了比较，以评估大变形的影响。对比结果表明，在小变形情况下，两种模态具有很好的一致性，而在大变形情况下，两种模态之间存在较大的差异，说明在设计中考虑大变形时必须考虑弹性效应。目前的工作为大变形薄板压电致动器的机电行为提供了基本的见解，从而提高了它们在先进结构中的应用性能。

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引用次数: 0