Smart Composite Panels Research Articles

A variable kinematic multi-field model for lamb wave propagation analysis in smart composite panels

The study explores the propagation of symmetric and antisymmetric fundamental Lamb waves in laminated composite strips, employing multi-field piezo-elastic plate models. The findings indicate the necessity of employing higher-order kinematic models to enhance the accuracy of wave propagation assessments. To further optimize computational efficiency, node-dependent kinematic models are utilized. The research delves into the tradeoff between reducing computational costs and maintaining result accuracy demonstrating a reduction of up to 60% in computational expenses in simple models while keeping the error below 1%. Two-dimensional wave propagation in laminated composite plates was further considered, expanding the scope due to material orthotropy.

Active aeroelastic flutter control of supersonic smart variable stiffness composite panels using layerwise models

This work focuses on the layerwise finite element modelling and active aeroelastic flutter control of smart variable stiffness laminated composite panels with surface bonded piezoelectric layers/patches under supersonic airflow. The proposed aero-electro-elastic models make use of the First- and Third-order Shear Deformation Theories, along with a linear through-thickness distribution of the electric potential, whereas the effect of the supersonic airflow is described by the First-order Piston Theory. Numerical applications of simply supported smart composite panels with either curvilinear or unidirectional fibres are provided for the accuracy assessment of the proposed models predictive capabilities, considering various side-to-thickness ratios and control conditions. The effect of proportional control on the aeroelastic flutter response is discussed for both airflow along the x-axis and yawed airflow, in addition to three different placement configurations of the piezoelectric patches.

Analysis of smart laminated composites integrated with piezoelectric patches using spectral element method and lamination parameters

This paper investigates the effect of stacking sequence on the power output of a smart composite panel integrated with piezoelectric patches, using lamination parameter formulation and spectral element method (SEM). The deformation of the panel is expressed using the first-order shear deformation theory. The strain energy of the host plate is formulated using lamination parameters and the governing equations are derived following Hamilton’s principle. To solve the governing equations accurately and efficiently, a spectral element method is applied where the structure is divided into regions that are continuous in terms of geometry, and element matrices of each region are calculated using the spectral Chebyshev approach. This method benefits both from the (geometry) flexibility of the finite element method and the accuracy of the meshless methods. The developed electromechanical model is used to study the effect of the number of piezo patches and their sizes. To demonstrate the accuracy and performance of the presented SEM, six case studies were investigated by comparing natural frequencies, structural/voltage frequency response functions (FRFs), and computational duration to those obtained from a finite element analysis (FEA). The maximum difference in the predicted natural frequencies between the SEM and FEA results is below 1% and the FRFs obtained using the presented solution technique excellently match the FEA results. Yet, the simulation duration is significantly reduced compared to FEA. To exploit the computational efficiency of the presented analysis approach, optimization case studies were also performed implementing a genetic algorithm to maximize the power output by optimizing the stacking sequence and patch distribution.

Piezoelasticity solution for edge stress field in weakly bonded piezoelectric composite laminates

The delamination/debonding failure in laminated structures is often caused by development of concentrated stress fields near the edges. Because of their three-dimensional (3D) nature, it is important to develop accurate elasticity solutions for these fields, which should include the possibility of non-rigid layer interfaces, to have realistic predictions. This article presents an accurate 3D piezoelasticity-based analytical solution for smart composite panels featured with piezoelectric sensor/actuator layers, having interfacial bonding imperfections and showing edge effects. The displacement and electric field discontinuities at the imperfectly bonded layer interfaces are represented by adopting the generalized spring–layer model. The model is implemented into the Reissner-type mixed variational principle for the piezoelectric medium. The partial differential equations thus developed are solved using the mixed-field multiterm Kantorovich method, which exactly satisfy all the mechanical and electric boundary conditions at the panel edges, top and bottom surfaces of the panel and interlaminar continuity/jump conditions. The accuracy and convergence of the present results are established in comparison with the available exact piezoelasticity solutions for simply supported panels. The effect of compliance and imperfection location on the electromechanical response of piezolaminated composite panels with edge effects is investigated. The influence of actuator debonding on the interlaminar stress transfer and actuation authority is also shown.

Multiscale finite element prediction of thermomechanical flexural strength of nanotube-reinforced hybrid smart composite panel bonded with SMA fibre

The influence of shape memory alloy (SMA) fibre embedding on the thermomechanical flexural strength of carbon nanotube (CNT) reinforced polymer composite structure has been predicted using multiscale-multi-physical finite element material model. To evaluate the structural bending responses, the smart composite model has been formulated mathematically in the framework of the higher-order polynomial kinematics including the shear deformation effect and necessary stress continuity. The structural bending due to the combined effect of mechanical loading and the elevated temperature is evaluated by solving the static equilibrium equations. The activation of functional material (SMA) has been achieved due to the variation of environmental conditions and the intrinsic material properties (prestrain and volume fraction) to arrest the excess structural deformations. This is the first time the effect SMA fibre i.e. memorizing the initial structural configuration has been introduced for the CNT reinforced composite via multiscale material model. The degree of structural strength improvement due to the activation of SMA has been computed numerically using the hybrid numerical algorithm considering the different scale and their physics. The current material model is consisting of two different techniques i.e., Mori-Tanaka scheme (randomly oriented CNT-reinforced composite) and the rule of mixture (CNT-polymer-SMA composite) to evaluate the hybrid composite elastic properties. The solution consistency and accuracy have been verified to illustrate the proposed finite element model authenticity. Lastly, a wide range of numerical examples is solved to show the model applicability and the outcomes highlighted in details by varying the source input parameters (geometry and material).

Geometrically nonlinear transient vibrations of actively damped anti-symmetric angle ply laminated composite shallow shell using active fibre composite (AFC) actuators

In present work, the thin laminated composite shallow shell as smart structure with AFC material’s ACLD treatment is analyzed for geometrically nonlinear transient vibrations. The AFC material is used to make the constraining layer of the ACLD treatment. Golla-Hughes-McTavish (GHM) is used to model the constrained viscoelastic layer of the ACLD treatment in time domain. Along with a simple first-order shear deformation theory the Von Kármán type non-linear strain displacement relations are used for deriving this electromechanical coupled problem. A 3-dimensional finite element model of smart composite panels integrated with the ACLD treated patches has been modelled to reveal the performance of ACLD treated patches on improving the damping properties of slender anti-symmetric angle-ply laminated shallow shell, in controlling the transient vibrations which are geometrically nonlinear. The mathematical results explain that the ACLD treated patches considerably enhance the damping properties of anti-symmetric angle-ply panels undergoing geometrically nonlinear transient vibrations.

Nonlinear flexural analysis of single/doubly curved smart composite shell panels integrated with PFRC actuator

Abstract This article deals with the geometrical nonlinear flexural behaviour of laminated composite shell panels integrated with the piezoelectric fibre reinforced composite (PFRC) layer. In this study, the PFRC embedded panel has been modeled mathematically using Green-Lagrange nonlinear kinematics in the framework of the higher-order shear deformation theory. Moreover, the quadratic variation of the electric potential has been considered. The nonlinear finite element steps have been adopted for the discretisation of the domain. Further, the principle of minimum potential energy in conjunction with the direct iterative method is implemented to compute the desired responses. The nonlinear numerical solutions have been validated by comparing the responses with those of the available published results. The actuating capability of the present PFRC layer to suppress the linear and the nonlinear deformations of the smart composite shell panels have been investigated by using the proposed higher-order nonlinear model. Finally, the effect of different geometrical parameters (thickness ratio, aspect ratio, curvature ratio, support constraints, shell geometry and piezoelectric fibre angle) on the nonlinear static behaviour of smart composite panels has been examined by solving various numerical examples.

Vibration behaviors of hybrid smart composites with SMA strips reinforced SMP lamina under blast loading

The dynamic responses of a hybrid smart composite incorporating shape memory alloys (SMAs) and shape memory polymers (SMPs) being exposed to blast loading are investigated. In order to use new and higher functions by combining the excellent qualities of both SMAs and SMPs, SMA strips reinforced with SMP lamina are sandwiched and adhered between two identical carbon fibers reinforced plastic. The recovery force of the SMA strips and the viscoelasticity of SMPs are applied to mitigate structural vibration induced by blast loading. Constitutive models for SMA strips and SMPs are established to observe their thermomechanical behaviors. Experimental tests of the SMAs and the SMPs are analyzed to acquire the parameters needed for the models. The responses of the hybrid smart composite panel are compared with those of the conventional composite panel taking into consideration the weight of the panels as the crucial design parameter for a fair comparison.

Optimal sensor positioning for impact localization in smart composite panels

Impacts can inflict critical consequences on composite structures; therefore, smart impact monitoring systems can be very helpful. A global optimisation of the piezoelectric sensors position for impact location identification is investigated in this article. The artificial neural networks and probabilistic analysis approach are used to define the objective function. Genetic algorithms are adopted to search for the optimal location of the sensors. The improved crossover and mutation functions are designed. The procedure is applied to a full-scale stiffened composite aircraft panel.

Active control of geometrically nonlinear transient vibrations of laminated composite cylindrical panels using piezoelectric fiber reinforced composite

This paper addresses the analysis of active constrained layer damping (ACLD) of geometrically nonlinear transient vibrations of laminated thin composite cylindrical panels using piezoelectric-fiber- reinforced composite (PFRC) materials. The constraining layer of the ACLD treatment is considered to be made of the PFRC materials. The Golla–Hughes–McTavish (GHM) method has been implemented to model the constrained viscoelastic layer of the ACLD treatment in time domain. The Von Karman type-nonlinear strain-displacement relations and a simple first-order shear deformation theory are used for deriving this electromechanical coupled problem. A three-dimensional finite element (FE) model of smart composite panels integrated with the patches of such ACLD treatment has been developed to demonstrate the performance of these patches on enhancing the damping characteristics of thin symmetric and antisymmetric laminated cylindrical panels in controlling the geometrically nonlinear transient vibrations. The numerical results indicate that the ACLD patches significantly improve the damping characteristics of both symmetric and antisymmetric panels for suppressing the geometrically nonlinear transient vibrations of the panels. The effect of the shallowness angle of the panels on the control authority of the patches has also been investigated.

Decentralized Robust Vibration Control of Smart Structures with Parameter Uncertainties

This study deals with decentralized robust vibration control of a smart composite panel with parameter uncertainties. The composite panel with four collocated piezoelectric actuators and velocity sensors is modeled using finite element method, and then the size of the model is reduced in the state space using Modal Hankel Singular Value. The parameter uncertainties presented by natural frequencies and modal damping ratios are considered in controller design process. To suppress the vibration induced by external disturbance, a decentralized robust H∞ controller is developed using linear matrix inequality techniques. Numerical simulation for the smart panel is performed in order to investigate the effectiveness of decentralized vibration control (DVC). When the system is subjected to an initial displacement field or distributed white noise disturbance, numerical results show that the DVC system is very effective. Although there are 20% parameter uncertainties for modal frequencies, damping ratio, and control input, the decentralized controller can effectively suppress the vibration excited by the external disturbance. Furthermore, the decentralized controller composed of four three-order systems can be practically implemented well.

Adaptive precision positioning of smart composite panels subjected to external disturbances

This paper addresses the simultaneous precision positioning and vibration suppression of smart composite panels with piezoelectric patches. The filtered-x least mean square (LMS) adaptive feedforward control (AFC) for vibration/noise reduction is extended for this purpose, and AFCs with feedback loops are developed. The introduced feedback loops enhance the computational efficiency of the adaptive LMS algorithm and vibration suppression capability. Besides the classic PID feedback loop, the internal model configuration is introduced as well for the case in which the external disturbance is unknown. Experiments are performed on an active composite panel under a harmonic or random disturbance. The effects of the convergence factors of the adaptive algorithm on the overshoot and settling time of the position response of the smart composite panel are investigated. The vibration suppression and precision positioning capabilities of the AFC and the AFC with feedback loops are compared and discussed. The experimental results demonstrate that the overall positioning and vibration suppression performances for the AFC with feedback loops are better than those for the AFC.

Smart damping of laminated thin cylindrical panels using piezoelectric fiber reinforced composites

In this paper performance of a new piezoelectric fiber reinforced composite (PFRC) material has been investigated for active constrained layer damping (ACLD) of laminated thin simply supported composite cylindrical panels. The constraining layer of the ACLD treatment has been considered to be made of this PFRC material. A finite element model of smart composite panels integrated with the patches of such ACLD treatment has been developed to demonstrate the performance of these patches on enhancing the damping characteristics of thin cross-ply and angle-ply laminated composite cylindrical panels. Particular emphasis has been placed on studying the effect of variation of the piezoelectric fiber orientation in the constraining PFRC layer and the shallowness angle of the panels on the control authority of the patches.

Development of Smart Composite Panel with Optical Fiber Sensors

We have developed a novel fiber-optic vibration sensors and applied commercially available strain and temperature sensors to health monitoring of composite structures. In this study, we constructed an optical fiber network integrating four types of optical fiber sensor into a carbon reinforced plastic (CFRP) panel. These four sensors were the vibration sensor developed by our laboratory, two distributed sensors based on Brillouin and Raman backscattering and Fiber Bragg Grating (FBG) sensors. By dealing the data obtained from the measurement systems corresponding to these four sensors, strain/stress and temperature distributions throughout the panel can be monitored. Vibration and elastic waves transmitting on the panel are also detected at several sensing points. Furthermore, we will be able to determine damage locations and modes by processing the wave signals. To make the panel with the optical fiber sensor network more sensitive and smarter, we are developing some techniques that can improve the performance of the sensors and can assess the structural integrity by analyzing measurement results. In this paper, the development of the first generation of our smart composite panel with the optical fiber sensors is described and the techniques making the panel more sensitive and smarter are also described.

Smart composite panels with embedded peak strain sensors

Composite laminates are finding increasing use in load bearing structures of a safety critical nature. This trend means that it becomes increasingly important to be able to measure the accumulated damage within safety critical composite panels. The current research approaches include the use of piezoelectric patches, fibre optics, and even the intrinsic piezoresistive properties of carbon fibres themselves. The aforementioned methods do, however, suffer various difficulties in terms of manufacturing considerations, as well as the complexities associated with some of the monitoring equipment needed to interpret damage levels. A more robust concept has however recently seen development, which relies on embedding metastable ferrous elements or wires within the laminate. Not only can this smart material easily withstand the processing temperatures; but if correctly used, the elements may impart significant load-bearing capacity to the laminate. The damage assessment equipment is simple and can in fact be operated by a person with no specialised training.