Jingjuan Zhai

Bio: Jingjuan Zhai is an academic researcher from Shenyang Aerospace University. The author has contributed to research in topics: Shell (structure) & Finite element method. The author has an hindex of 4, co-authored 8 publications receiving 37 citations. Previous affiliations of Jingjuan Zhai include Dalian University of Technology.

Integrated design optimization of structural size and control system of piezoelectric curved shells with respect to sound radiation

Abstract: Simultaneously optimizing the thickness of the base structure and the location of piezoelectric sensors/actuators as well as control gains is investigated for minimizing the sound radiation from the vibrating curved shell integrated with sensors/actuators under harmonic excitation. The finite element formulation of the piezoelectric curved shell structure is described. The piezoelectric element is coupled into the base shell element using nodal displacement constraint equations. The active control of structural vibration-acoustic radiation is formulated using the velocity feedback algorithm. Based on both passive and active control measures, an integrated optimization model of the vibro-acoustic problem is proposed, in which the sound power is taken as the objective function. The thickness of the base shell elements and the parameters of control system, including the location of sensors/actuators and control gains, are chosen as the design variables. In order to restrict the complexity of the control system, the number of sensors/actuators is considered as a constraint. A simulated annealing algorithm is extended to handle the vibro-acoustic optimization problem with the continuous and discrete variables co-existing. Numerical examples demonstrate the effectiveness of the optimization scheme and the correctness of the computation program.

Integrated design optimization of structure and vibration control with piezoelectric curved shell actuators

Abstract: The investigation focuses on simultaneously optimizing the locations and thicknesses of piezoelectric curved actuators as well as transient control voltages to achieve the best performance index. A...

Topology optimization for coupled acoustic-structural systems under random excitation

Abstract: Topology optimization for coupled acoustic-structural systems subjected to stationary random excitations is investigated. Bi-material elastic continuum structures without damping are considered. The finite element method is utilized to deal with coupled acoustic-structural problems. An accurate and highly efficient algorithm series for stationary random analysis techniques, pseudo excitation method, is extended to calculate the acoustic random response generated by the vibrating structures. Minimization of the auto power spectral density of sound pressure is taken as design objective and its sensitivities with respect to topological variables are derived by adjoint method. A penalty term is proposed to suppress the intermediate volumetric densities. Numerical examples are given to demonstrate the validity of the presented methods.

Topology optimization of piezoelectric curved shell structures with active control for reducing random vibration

Abstract: This paper investigates topology optimization of the surface electrode coverage on piezoelectric sensor/actuator layers attached to a curved shell structure subjected to stationary random force excitation, with the aim to minimize the random vibration response under active control. In the optimization model, the power spectral density (PSD) of displacement response at the specified point is considered as the objective function. The pseudo-densities describing the surface electrode distribution are assigned as the design variables, and an artificial active damping model with penalization is employed to suppress intermediate density values. The voltage across each actuator is determined by velocity feedback control law. Pseudo excitation method (PEM) is introduced to analyze random vibration response of a piezoelectric curved shell structure with active control. In this context, the adjoint variable method for the sensitivity analysis of displacement PSD with respect to topological design variables is derived. Numerical examples fully demonstrate the validity of the proposed approach.

Review on the use of piezoelectric materials for active vibration, noise, and flow control

Abstract: Considering the number of applications, and the quantity of research conducted over the past few decades, it wouldn't be an overstatement to label the piezoelectric materials as the cream of the crop of the smart materials. Among the various smart materials, the piezoelectric materials have emerged as the most researched material for practical applications. They owe it to a few key factors like low cost, large frequency bandwidth of operation, availability in many forms, and the simplicity offered in handling and implementation. For piezoelectric materials, from an application standpoint, the area of active control of vibration, noise, and flow, stands, alongside energy harvesting, as the most researched field. Over the past three decades, several authors have used piezoelectric materials as sensors and actuators, to (i) actively control structural vibrations, noise and aeroelastic flutter, (ii) actively reduce buffeting, and (iii) regulate the separation of flows. These studies are spread over several engineering disciplines-starting from large space structures, to civil structures, to helicopters and airplanes, to computer hard disk drives. This review is an attempt to concise the progress made in all these fields by exclusively highlighting the application of the piezoelectric material. The research carried out in the past five years, in the areas of modeling, and optimal positioning of piezoelectric actuators/sensors, for active vibration control, are covered. Along with this, investigations into different control algorithms, for the piezoelectric based active vibration control, are also reviewed. Studies reporting the use of piezoelectric modal filtering and self sensing actuators, for active vibration control, are also surveyed. Additionally, research on semi-active vibration control techniques like the synchronized switched damping (on elements like resistor, inductor, voltage source, negative capacitor) has also been covered

Vibrational behavior of doubly curved smart sandwich shells with FG-CNTRC face sheets and FG porous core

Abstract: As a first endeavor, the free flexural vibration behavior of doubly curved complete and incomplete sandwich shells with functionally graded (FG) porous core, FG carbon nanotube reinforced composite (FG-CNTRC) face sheets and integrated piezoelectric layers is investigated. The variable radii shells with the three most common types of geometries, i.e., elliptical, cycloid and parabolic, are considered. The system equations are derived based on the general higher-order shear deformation theory and Maxwell's equation. The generalized differential quadrature (GDQ) method is employed to discretize the governing partial differential equations subjected to different boundary conditions. The accuracy and reliability of the approach are verified by comparing the results with the existing solutions in open literature. The effects of porosity parameter and porosity distribution through the thickness direction, carbon nanotube (CNT) volume fraction, different boundary conditions and various shell geometrical parameters on the flexural vibrational behavior of the smart sandwich shell structures are investigated and useful results are presented.

Topology optimization of piezoelectric macro-fiber composite patches on laminated plates for vibration suppression

Abstract: This work presents a new methodology for the topology optimization of piezoelectric actuators in laminated composite structures with the objective of controlling external perturbation induced by structural vibrations. The linear-quadratic regulator (LQR) optimal control technique is used and the topology optimization is formulated seeking to find the optimum localization of the macro-fiber composite (MFC) active piezoelectric patch by means of the maximization of the controllability index. For the structural model, we propose a simplified MFC/structure interaction model. It is assumed that the MFC is one of the orthotropic material layers with an initial strain arising from the application of an electric potential. This strain acts on the remainder of the structure and its effect is considered analytically. Numerical results show that the proposed MFC structure interaction model presents good agreement with experiments and numerical simulations of models that take into account the electromechanical effect. Results of the actuator location optimization show that the implemented technique improves the structural vibration damping. Results and comparisons are presented for the vibration control strategy using the LQR controller.