Electromechanical Coupling Problem Research Articles

Electromechanical Coupling and Application of High-Frequency Communication Antenna Channel Capacity

The next-generation communication base station antennas represented by phased array antennas are towards high frequency, high gain, high density, and high pointing accuracy. The influence of mechanical structure factors on communication system channel quality is obviously increasing, and the electromechanical coupling problem is becoming more prominent. To effectively guarantee the realization of 5G/6G communication in complex working environments and accelerate the commercial process of future communication systems, an electromechanical coupling channel capacity model is established in comprehensive consideration of the positional shift, attitude deflection, and temperature change of the communication base station phased array antennas. It can be used to rapidly evaluate the communication index degradation of RF devices within the heating environment. Moreover, a sensitivity model of the electric field strength and array antenna channel capacity to the random position error of each element is constructed. The influence of the random positioning error of each element on the communication indicators is analyzed and compared under different working conditions. The simulation results show that the proposed model can effectively provide a theoretical basis and guiding role for the design and manufacture of high-frequency array base station antennas.

Preface

Due to recent pandemic, 2022 3rd International Conference on Mechanical Instrumentation and Automation (ICMIA 2022) was held virtually online during March 25-27, 2022. The decision to hold the virtual conference was made in compliance with many restrictions and regulations that were imposed by countries around the globe. Such restrictions were made to minimize the risk of people contracting or spreading the COVID-19 through physical contact. There were 80 individuals who attended this on-line conference, represented many countries including Malaysia, Singapore, Indonesia, Brazil and China. ICMIA 2022 is to bring together International Symposium on Mechanical Instrumentation and Automation to a common forum. And another goal is to promote scientific information interchange between researchers, developers, engineers, students, and practitioners working all around the world. The conference will be held every year to make it an ideal platform for people to share views and experiences in International Symposium on Mechanical Instrumentation and Automation and related areas. During the conference, the conference model was divided into three sessions, including oral presentations, keynote speeches, and online Q&A discussion. In the first part, some scholars, whose submissions were selected as the excellent papers, were given about 5-10 minutes to perform their oral presentations one by one. Then in the second part, keynote speakers were each allocated 30-45 minutes to hold their speeches. In the second part, we invited four professors as our keynote speakers. Prof. Hamid Reza Karimi, Politecnico di Milano, Italy. His original research and development achievements span a broad spectrum within the topic of control systems, mechatronics, intelligent systems, and fault diagnosis with applications such as vehicles, robotics and manufacturing systems. And then we had Prof. Na Li, Xidian University, China. Her research focused on the error theory of electronic equipment, multi-scale electromechanical coupling problems, and the design and optimization of new nanoelectronic equipment structures. Assoc. Prof. Mohamed Arezki Mellal, M’Hamed Bougara University, Algeria. His research interests include developing new nature-inspired optimization methods for solving engineering problems of system dependability, design, manufacturing, and energy efficiency. Finally, we had Assoc. Prof. Lisu Yu, Nanchang University, China as our finale keynote speaker. Their insightful speeches had triggered heated discussion in the third session of the conference. Every participant praised this conference for disseminating useful and insightful knowledge. List of Committee member are available in this pdf.

Experimental Observation and Modelling of the Electroplastic Effect in Nonferromagnetic Ductile Metals

In this study, an innovative methodology to experimentally distinguish the ElectroPlastic (EP) effect from the thermal expansion and thermal softening was developed and applied to validate the proposed theoretical electro-mechanical model. Two series of quasi-static uniaxial tension experiments with titanium and copper were conducted and a quadratic dependence was observed of the EP strain on the electric current density, corrected for increased dislocation density levels. This study experimentally confirmed the existence of EP phenomenon in ductile metals. The significance of the non-EP effects in the electro-mechanical coupling problems was estimated and the experimental procedure limitations were thoroughly discussed as well as the sensitivity and uncertainty, associated with each of the model parameters. Conclusions and suggestions for future work supplement the study. This piloting work on electro-mechanical coupling provides a solid foundation for further modelling and experimental observation of the electroplastic effect.

Research on operating domain optimization of power split hybrid electric vehicle based on global bifurcation and chaos threshold

The power-split hybrid electric vehicle (PS-HEV) has multiple working modes to maintain high operation efficiency according to different conditions. The main modes involved in the vehicle driving process are pure electric mode and the hybrid driving mode. Because the electromechanical coupling problem is involved in the above two working modes, the transmission system exhibits strong non-linear characteristics. If the operation range of the engine and motor are unreasonable, the rotor system will vibrate and become instability. In this paper, the non-linear dynamic equations of the electromechanical coupling of the transmission system are established for electric driving mode and hybrid driving mode. The closed-homoclinic phase trajectory equation at the center point of the disturbance-free Hamilton system is determined. The chaotic thresholds for the pure electric and hybrid driving modes are derived through the Melnikov’s method to obtain the optimal working domain of the engine and motor. Finally, numerical simulation analysis is conducted to verify the feasibility of the work domain optimization scheme. Simulation results show that the proposed engine and motor working area optimization scheme can effectively avoid the homoclinic bifurcation in the PS-HEV during the driving process and prevent the vehicle from entering the chaotic state.

Electromechanical decoupled model for cantilever-beam piezoelectric energy harvesters

Analysis of cantilever-based piezoelectric energy harvesting systems is usually performed using coupled equations that represent the mechanical displacement and the voltage output. These equations are then solved simultaneously. In contrast to this representation, we use analytical solutions of the governing equation to derive an algebraic equation of the power as a function of the beam displacement, electromechanical coefficients, and the load resistance. Such an equation can be more useful in the design of such harvesters. Particularly, the mechanical displacement is computed from a mechanical governing equation with modified natural frequency and damping ratio that account for the electromechanical coupling. The voltage and the harvested power are then obtained by relating them directly to the mechanical displacement. We validate the proposed analysis by comparing its solution including the tip displacement and harvested power with those of numerical simulations of the governing equations. To demonstrate the generality of the proposed approach, we consider the cases of base excitation, galloping, and autoparametric vibration. The model proposed in this study simplifies the electromechanical coupling problem for practical applications of cantilever-beam piezoelectric energy harvesting systems.

A Finite Element Method for Inhomogeneous Deformation of Viscoelastic Dielectric Elastomers

Viscoelasticity is known to adversely affect the performance of a dielectric elastomer actuator and limit its application. In this paper, we present a finite element method for dielectric elastomers based on a nonlinear field theory that couples viscoelasticity and electrostatics. This method is implemented in a commercial finite element software. We use the method to solve electromechanical coupling problems of viscoelastic dielectric elastomers under inhomogeneous deformation in various configurations.

电子装备机电耦合研究的现状与发展

High-performance and highly accurate electronic equipment are utilized in various areas on land, in the sea, in the air, and in outer space. As a prelude to exploring the electromechanical coupling problem in electronic equipment, this paper first gives a broad overview of the state-of-the-art in electronic equipment, including concept, theory, and methodology, problem areas, hot spots, research progress, and new trends in the field. Consequently, typical examples of electronic equipment are discussed, including the microwave re ector antenna, plate-slot array antenna, active phased array antenna, and high density chassis.

Review of electromechanical coupling of electronic equipment

High-performance and highly accurate electronic equipment are utilized in various areas on land, in the sea, in the air, and in outer space. As a prelude to exploring the electromechanical coupling problem in electronic equipment, this paper first gives a broad overview of the state-of-the-art in electronic equipment, including concept, theory, and methodology, problem areas, hot spots, research progress, and new trends in the field. Consequently, typical examples of electronic equipment are discussed, including the microwave re ector antenna, plate-slot array antenna, active phased array antenna, and high density chassis.

A 2D Electromechanical Model of Human Atrial Tissue Using the Discrete Element Method.

Cardiac tissue is a syncytium of coupled cells with pronounced intrinsic discrete nature. Previous models of cardiac electromechanics often ignore such discrete properties and treat cardiac tissue as a continuous medium, which has fundamental limitations. In the present study, we introduce a 2D electromechanical model for human atrial tissue based on the discrete element method (DEM). In the model, single-cell dynamics are governed by strongly coupling the electrophysiological model of Courtemanche et al. to the myofilament model of Rice et al. with two-way feedbacks. Each cell is treated as a viscoelastic body, which is physically represented by a clump of nine particles. Cell aggregations are arranged so that the anisotropic nature of cardiac tissue due to fibre orientations can be modelled. Each cell is electrically coupled to neighbouring cells, allowing excitation waves to propagate through the tissue. Cell-to-cell mechanical interactions are modelled using a linear contact bond model in DEM. By coupling cardiac electrophysiology with mechanics via the intracellular Ca2+ concentration, the DEM model successfully simulates the conduction of cardiac electrical waves and the tissue's corresponding mechanical contractions. The developed DEM model is numerically stable and provides a powerful method for studying the electromechanical coupling problem in the heart.

Analysis of the Electro-Mechanical Responses of the Piezoelectric Motor Based on Finite Element Method

The piezoelectric field and structure field of piezoelectric resonator of ultrasonic motor are intercoupling. It is difficult to obtain the solution under some circumstances because of the complex stress boundary condition and the influence of coupling effect. An electro-mechanical coupling finite-element dynamic equation is established on the basis of the Hamilton’s Principle about piezoceramic and elastomer. The equation is decoupled through the shock excitation of the piezoelectric resonator and the piezoelectricity element and material provided by finite-element analysis. As a result, an admittance curve as well as the distribution status of the nodal DOF is obtained, which provides an effective method to solve electro-mechanical coupling problems.

A finite element method for dielectric elastomer transducers

We present a finite element method for dielectric elastomer (DE) transducers based on the nonlinear field theory of DE. The method is implemented in the commercial finite element software ABAQUS, which provides a large library functions to describe finite elasticity. This method can be used to solve electromechanical coupling problems of DE transducers with complex configurations and under inhomogeneous deformation.

Inclusion of arbitrary polygon with graded eigenstrain in an anisotropic piezoelectric full plane

In this paper, an exact closed-form solution for the Eshelby problem of a polygonal inclusion with a graded eigenstrain in an anisotropic piezoelectric full plane is presented. For this electromechanical coupling problem, by virtue of Green’s function solutions, the induced elastic and piezoelectric fields are first expressed in terms of line integrals on the boundary of the inclusion. Using the line-source Green’s function, the line integral is then carried out analytically for the linear eigenstrain case, with the final expression involving only elementary functions. Finally, the solution is applied to the semiconductor quantum wire (QWR) of square, triangle, circle and ellipse shapes within the GaAs (001) substrate. It is demonstrated that there exists significant difference between the induced field by the uniform eigenstrain and that by the linear eigenstrain. Since the misfit eigenstrain in most QWR structures is actually non-uniform, the present solution should be particularly appealing to nanoscale QWR structure analysis where strain and electric fields are coupled and are affected by the non-uniform misfit strain.

전기-기계 연성해석 코드 ATILA를 이용한 수중 음향 트랜스듀서 설계

Underwater acoustic transducers are widely used for SONAR application, whose important design parameters are shapes. materials, dimensions and supporting structures. Practical design method of transducers consists of manufacturing, experiments and modifications so that it requires much time and expenses. In this study, an analytical method was developed for the Tonpilz type transducers using the commercial finite element analysis code ATILA which can solve the electro-mechanical coupling problems. A finite element model was established including the transducer elements such as ceramic stack, head mass, tail mass, tensile bolt, and molding layers. The proposed model was verified and modified by comparing the in-air and in-water test results of prototypes. The developed analysis method will be effectively used for the sensitivity analysis of design parameters in transducer design process.

A sub-layer model for a thick piezoelectric patch bonded on elastic substrate

In this paper, the two-dimensional electromechanical coupling problems that a piezoelectric patch of finite size bonded to an elastic substrate are considered. A subdivision model that the single physical piezoelectric layer is mathematically divided into a number of thinner layers is proposed to analyze the electromechanical responses of the structures. Within each virtual sub-layer of the piezoelectric patch the electric displacement and normal stress in the axial direction are assumed to be linear functions of the thickness coordinate. Hellinger-Reissner variational principle for elasticity is extended to the systems of piezoelectric multi-materials. The governing equations that comprise one-dimensional differential equations and integro-differential equations are rigorously derived from the stationary conditions of the variational functional along with substitution of the assumed electromechanical fields. The subdivision model satisfies all mechanical and electric continuity conditions across the virtual interfaces and the physical interface of piezoelectrics/substrate. The numerical solutions of the governing equations are conducted, and the convergence of the subdivision model is demonstrated.

Domain switching and non-linear coupling of ferroelectric composites

One of the most notable characteristics of ferroelectric materials is that they could undergo spontaneous polarization and spontaneous strain changes by applied fields. Reorientation of the spontaneous polarization and spontaneous polarization strain of ferroelectric inclusions in ferroelectric composites can change microstructures and affect effective electroelastic properties of ferroelectric composites. Based on orientation distribution function and its evolution as well as switching criterion, non-linear electromechanical coupling behaviour of ferroelectric composites is studied by application of micromechanics. A constitutive model of ferroelectric composites is developed. Comparison between analytical and experimental results shows that the model presented can describe many non-linear electromechanical coupling problems of ferroelectric composites such as polarization or depolarization, etc.