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三层压电梁结构在电场作用下发生变形后会产生诱发电势,进而改变材料整体电势分布,本文考虑此变形和电势耦合效应,基于欧拉-伯努利梁变形理论,推导出能够准确预测压电智能悬臂梁传感器与驱动器性能的解析表达式。考虑压电梁结构弯曲变形后产生的电场影响,建立了三层压电梁结构的控制方程;建立了压电梁作为驱动器时端部输出位移、驱动力矩与输入电压之间联系的解析表达式,以及作为传感器时输出电压与端部作用力之间联系的解析表达式。通过与ANSYS有限元模拟结果以及传统的驱动器和传感器性能表达式的对比,验证了所推导的解析表达式的准确性。 相似文献
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An efficient quadrilateral element, recently developed by the authors, based on an improved zigzag theory is assessed for the static electromechanical response of hybrid plates with electroded piezoelectric sensors and actuators. The theory accounts for the transverse normal strain due to the electric field in the approximation of deflection. The electric potential is approximated as layerwise quadratic across the thickness. By introducing an electric node in the element for the electric potentials of the electroded piezoelectric surfaces, the equipotential condition of such surfaces is modelled very efficiently. The electric potential degrees of freedom (DOF) corresponding to the quadratic component of the electric potential distribution are associated with the four physical nodes to allow for the inplane electric field induced due to direct piezoelectric effect. The requirement of C1 continuity of interpolation functions of the deflection is circumvented by employing the improved discrete Kirchhoff constraint technique. The finite element (FE) formulation is validated by comparing the results with other available results in the literature. Comparison of the present results for static response of a variety of piezoelectric bimorph, hybrid composite and sandwich plates, with 3D analytical and FE solutions and those of other available elements establishes that the present element is accurate, robust and computationally efficient. 相似文献
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为了描述离子聚合物金属复合材料(ionic polymer metal composites, 简称IPMC)悬臂型驱动器在直流电激励下的非线性大变形行为,采用数字图像相关法(digital image correlation, 简称DIC)获得的IPMC应变梯度与激励电压间的关系,与修正后的IPMC电极分布式电阻电容(resistor-capacitor, 简称RC)电路模型相结合,提出了一种具有解析解的IPMC弯曲大变形力-电耦合模型,并采用Pt电极和Ag电极两种IPMC试样对该模型进行了实验验证。结果表明,该模型能够准确地反映IPMC悬臂型驱动器在直流电激励下的整体弯曲变形现象,且适用于采用沉积法制备电极的IPMC驱动器。 相似文献
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为解决变体机翼中蒙皮大变形与承载力之间的矛盾,同时满足光顺性及疲劳寿命的要求,提出了一种以形状记忆合金板为驱动元件的双程弯曲驱动器。基于形状记忆效应及材料力学弯曲理论,通过对驱动器变形过程中的力学特性进行分析,推导出双程弯曲驱动器的设计理论,再利用热成形法与反变形训练法制备出驱动器样件并进行了变形性能测试。研究结果表明:依据推导出的理论所设计的形状记忆合金双程弯曲驱动器的变形量与试验结果一致;随着加热温度的升高,驱动器的挠度及输出力逐渐增大,直至达到最大值;随着回复弹簧钢板厚度的增大,驱动器的最大挠度及最大输出力减小,加热变形响应速度减慢,但冷却回复响应速度加快;经过循环激励后,驱动器的变形效果稳定。 相似文献
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The coupling effects between the mechanical and electric properties of piezoelectric materials have drawn significant attention
for their potential applications as sensors and actuators. In this investigation, two piezoelectric actuators are symmetrically
embedded in a simply supported plate. Electric voltages with the same amplitude and opposite sign are applied to the two symmetric
piezoelectric actuators, resulting in the bending effect on the plate. The bending moment is derived by using the theories
of elasticity and piezoelectricity. The analytical solution of the flexural displacement of a simply supported plate subjected
to the bending moment is solved by using the plate theory. The analytical solution is compared with the finite element solution
to show the validation of present approach. The effects of the size and location of the piezoelectric actuators on the response
of a plate are presented through a parametric study. 相似文献
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基于有限元法对三辊非对称滚弯成形工艺进行了研究,对比分析了三辊非对称滚弯成形和三辊对称滚弯成形过程中,变形区应力场、板材上表面的塑形应变场及卷制力的变化规律。仿真结果表明:侧辊位移进给量相同的工况下,三辊非对称滚弯成形的卷制力大于三辊对称滚弯成形的卷制力;三辊非对称滚弯变形区的纵向应力和径向应力均大于三辊对称滚弯成形的纵向应力和径向应力;三辊非对称滚弯成形板材压弯段的成形质量高于三辊对称滚弯成形的成形质量。最后,经三辊非对称滚弯试验验证,有限元模型的成形误差为6.8%,有较高的精度。 相似文献
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Nonlinear free and forced vibration of simply supported shear deformable laminated plates with piezoelectric actuators 总被引:3,自引:0,他引:3
This paper deals with the nonlinear vibration and dynamic response of simply supported shear deformable cross-ply laminated plates with piezoelectric actuators subjected to mechanical, electrical and thermal loads. The material properties are assumed to be independent of the temperature and electric field. Theoretical formulations are based on the higher order shear deformation plate theory and general von Kármán-type equation, which includes thermo-piezoelectric effects. Due to the bending and stretching coupling effects, a nonlinear static problem is first solved to determine the pre-vibration deformation caused by temperature field and control voltage. By adding an incremental dynamic state to the pre-vibration state, the equations of motion are solved by an improved perturbation technique to determine nonlinear frequencies and dynamic responses of hybrid laminated plates. The numerical illustrations concern nonlinear vibration characteristics of unsymmetric cross-ply laminated plates. The results presented show the effects of temperature rise, applied voltage and stacking sequence on the nonlinear vibration and dynamic response of the plates. 相似文献
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数值模拟中的模拟方法对于建立一个可信赖的有限元模型非常重要。板料成形中包含大变形、大位移和摩 擦行为,模拟结果对不同的有限元模型有很大的不确定性。采用有限元软件MARC基于不同拉格朗日法建立了一 个有限元模型来分析深冲压成形过程。模拟中板料作为变形体,模具看作刚体,接触面间的摩擦约束采用修正的库 仑摩擦模型。板料应变、厚度的模拟和实验结果比较表明完全拉格朗日法(T.L.)和更新拉格朗日法(U.L.)的主 要区别在大变形和大位移上,小变形和小位移两者吻合较好。 相似文献
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Liu Y Zhou W Cui K Tian N Wang X Liu L Li L Zhou Y 《The Review of scientific instruments》2011,82(4):045104
We designed and constructed an extensional rheometer for in situ small and wide angle x-ray study on flow-induced crystallization of polymer. Two rotating drums with an axis distance of 20 mm are employed to impose extensional deformation on the samples. With a constant angular velocity, the two drums generate a constant Henkcy strain rate as sample length for testing keeps constant during deformation. An ionic liquid is used as heating medium to prevent polymer melt from bending downward due to gravity, which is excellent in terms of high thermal stability, low viscosity, and relative low adsorption on x-ray. Flow-induced crystallization experiments are conducted with this apparatus on x-ray scattering station in Shanghai Synchrotron Radiation Facility (SSRF), which allows us to collect rheological and structural data simultaneously and may lead to a better understanding on flow-induced crystallization of polymer. 相似文献
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In order to improve quarter waves occurred in the wide and thin gauged alloy steel rolled by 20-high sendzimir mill, a computer simulation based on the divided element method and an actual cold rolling experiment were carried out. Quarter waves were simulated by elastic deformation analysis of rolls considering bending deformation of back up rolls and the effect of control actuators on controllability of quarter waves were analyzed. Computer simulation showed that control actuators such as shifting of the 1st intermediate roll and crown adjustment of As-U-Roll in back up rolls were not effective to control quarter waves and that changing taper mode (both length and magnitude) at the barrel-end taper radius of the 1st intermediate roll was rather very effective. From an actual rolling experiment it was verified that quarter waves could be reduced remarkerably by changing taper mode of the 1st intermediate roll. 相似文献
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Jyh-Horng Chou Shinn-Horng Chen Min-Yung Chang An-Jia Pan 《International Journal of Mechanical Sciences》1997,39(7):751-760
In this paper, a time domain approach is presented to treat the problem of active controlling simultaneously the bending and torsional vibration of flexible composite beams under both mode truncations and parameter perturbations. In the proposed approach, the residual model, which is known as unstructured uncertainty, is viewed as an additive perturbation to the controlled model. Based on a state space model, which incorporates both bending and torsional deformation effects, of the flexible composite beam with piezoelectric sensors and actuators, a robust stability condition is derived to guarantee that both bending and torsional vibration of the flexible composite beam, which is subject to both mode truncation and linear time-varying parameter perturbations, can be actively controlled by an observer-based controller. The proposed robust stability condition gives an insight into the relationship between the stability margins of the controlled and residual mode subsystems, spillover effects and additive time-varying parameter perturbations. Finally, an active robust vibration control problem of a cantilevered flexible composite beam with piezoelectric sensors and actuators is provided for illustration. 相似文献
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Pneumatic actuators and electric actuators have almost been applied to all manufacturing industries. The two kinds of actuators can replace each other in most fields, such as the point to point transmission occasion and some rotating occasions. However, there are very few research results about the advantages and disadvantages of two kinds of actuators under the same working conditions so far. In this paper, a novel comprehensive assessment method, named as overall life cycle comprehensive assessment (OLCCA), is proposed for comparison and assessment of pneumatic and electric actuators. OLCCA contains mechanical properties evaluation (MPE), life cycle cost analysis based on users (LCCABOU) and life cycle environmental impact analysis (LCEIA) algorithm in order to solve three difficult problems: mechanical properties assessment, cost analysis and environmental impact assessment about actuators. The mechanical properties evaluation of actuators is a multi-objective optimization problem. The fuzzy data quantification and information entropy methods are combined to establish MPE algorithm of actuators. Two kinds of pneumatic actuators and electric actuators with similar bearing capacity and similar work stroke were taken for example to verify the correctness of MPE algorithm. The case study of MPE algorithm for actuators verified its correctness. LCCABOU for actuators is also set up. Considering cost complex structure of pneumatic actuators, public device cost even method (PDCEM) is firstly presented to solve cost division of public devices such as compressors, aftercooler, receivers, etc. LCCABOU method is also effective and verified by the three groups of pneumatic actuators and electric actuators. Finally, LCEIA model of actuators is established for the environmental impact assessment of actuators. LCEIA data collection method and model establishment procedure for actuators are also put forward. With Simapro 7, LCEIA comparison results of six actuators can be obtained: Fossil fuels are the major environmental factor of pneumatic and electric actuators; Environmental impact of electric actuator is large than one of pneumatic actuator under the similar mechanical properties and working conditions of pneumatic and electric actuators. The results are correct and correspond with the actual mechanical properties of actuators. This paper proposes a comprehensive evaluation method of the actuators, which can solve the critical problem that similar electromechanical products are very difficult to be compared with each other from the angle of performance, cost and environment impact. 相似文献
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SUZUKI Katsiyoshi 《机械工程学报(英文版)》2007,20(2):73-76
A rectangular bimorph will vibrate in bending mode under alternating current (AC) electric field. If two opposite tips along longitudinal direction are both clamped,the maximum magnitude of bending displacement occurs on the short center line. Using bimorph type vibrators forementioned as actuators,an invention of simple traveling machine based on stick-slip principle is presented. The machine can not only move along both x and y direction within horizontal working plane,further-more,excellent bearing ability and agile response as well as stable step are also proved. In addition,the machine can work on stepping mode and scanning mode at the same time,hence the contradiction between long stroke and high precise positioning is solved. Therefore,it meets the needs of mi-cro/nanometer precise positioning under long stroke and is desired to be used as carrying stage for micro-assembling system and locomotive mechanism for miniature robot system. 相似文献
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基于Maxwell 3D的汽车电磁缓速器瞬态电磁场有限元分析与仿真 总被引:1,自引:0,他引:1
文中根据电磁场理论,引入电磁位对和库仑规范,推导了汽车电磁缓速器电磁场的控制方程,采用主、从边界建立了其有限元模型,并对汽车电磁缓速器的瞬态电磁场进行了仿真,分析了仿真结果,可作为汽车电磁缓速器的进一步研究基础. 相似文献
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Structural aspects of organic molecular films, such as disordering, packing density, molecular bending or tilts, and phase separation, influence electrical properties as well as friction and adhesion. This indicates a correlation between nanomechanical and charge transport properties of molecular films at the molecular scale. In this review, we highlight the recent studies on correlations between charge transport and nanomechanical properties probed with atomic force microscopy. We discuss the key issues that determine charge transport and nanomechanical properties on several organic molecular films, including self-assembled monolayers formed by saturated hydrocarbon molecules conjugated molecules, and hybrid molecules as well as polymer and polymer blend films. We address the role of molecular deformation and bending in friction and conductance measurements. 相似文献
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该文从电动执行机构的机理和现场应用存在的问题出发,重点介绍了针对传统电动执行机构技术改造的位置调整模块的设计要点。 相似文献
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