Showing papers in "Journal of Intelligent Material Systems and Structures in 2014"
TL;DR: In this article, the use of microfibres is proposed to control the crack width and thus to promote the self-healing efficiency, which is also enhanced by the application of superabsorbent polymers.
Abstract: Concrete cracks due to its low tensile strength. The presence of cracks endangers the durability as they generate a pathway for harmful particles dissolved in fluids and gases. Without a proper treatment, maintenance costs will increase. Self-healing can prevail in small cracks due to precipitation of calcium carbonate and further hydration. Therefore, the use of microfibres is proposed to control the crack width and thus to promote the self-healing efficiency. In the current research, crack sealing is also enhanced by the application of superabsorbent polymers. When cracking occurs, superabsorbent polymers are exposed to the humid environment and swell. This swelling reaction seals the crack from intruding potentially harmful substances. Mortar mixtures with microfibres and with and without superabsorbent polymers were investigated on their crack sealing and healing efficiency. Regain in mechanical properties upon crack healing was investigated by the performance of four-point-bending tests, and the seal...
345 citations
TL;DR: In this article, the authors proposed a method for vibration energy harvesting using piezoelectric material, which has received great research interest in the recent years, and one of the important concern for the development of PEG is to minimize the energy consumption.
Abstract: Vibration energy harvesting using piezoelectric material has received great research interest in the recent years. One important concern for the development of piezoelectric energy harvesting is to...
131 citations
TL;DR: In this paper, a comparative experimental investigation of the aerodynamic properties of the Fish Bone Active Camber morphing structure has been conducted, and a biologically inspired concept has been proposed.
Abstract: This work presents comparative experimental investigations into the aerodynamics of the recently proposed Fish Bone Active Camber morphing structure. This novel, biologically inspired concept consi...
129 citations
TL;DR: In this article, a nonlinear distributed-parameter model for harvesting energy from vortex-induced vibrations of a piezoelectric cantilever beam with a circular cylinder attached to its end is presented.
Abstract: A nonlinear distributed-parameter model for harvesting energy from vortex-induced vibrations of a piezoelectric cantilever beam with a circular cylinder attached to its end is developed and validat...
125 citations
TL;DR: In this paper, the effects of shape variations of a cantilever beam on its performance as an energy harvester were investigated and a reduced-order model based on a one-mode Galerkin approach was derived.
Abstract: We investigate the effects of shape variations of a cantilever beam on its performance as an energy harvester. The beam is composed of piezoelectric and metallic layers (unimorph design) with a rigid mass attached to its free end. A reduced-order model based on a one-mode Galerkin approach is derived. Solutions for the tip displacement, generated voltage, and harvested power are then obtained. Linear and quadratic shape variations are considered in order to design piezoelectric energy harvesters that can generate energy at low frequencies and maximize the harvested energy. The results show that the fundamental natural frequency and mode shape are strongly affected when the shape of the beam is varied. The influence of the electrical load resistance and the shape parameters at resonance on the system’s performance is discussed. It is determined that for specific resistance values, the quadratic shape can yield up to two times the energy harvested by a rectangular shape.
120 citations
TL;DR: In this article, the authors presented predictive modeling of nonlinear guided wave propagation for structural health monitoring using both finite element method and analytical approach, where the nonlinearity of the guided waves is generated by interaction with a nonlinear breathing crack.
Abstract: This article presents predictive modeling of nonlinear guided wave propagation for structural health monitoring using both finite element method and analytical approach. In our study, the nonlinearity of the guided waves is generated by interaction with a nonlinear breathing crack. Two nonlinear finite element method techniques are used to simulate the breathing crack: (a) element activation/deactivation method and (b) contact analysis. Both techniques are available in ANSYS software package. The solutions obtained by these two finite element method techniques compare quite well. A parametric analytical predictive model is built to simulate guided waves interacting with linear/nonlinear structural damage. This model is coded into MATLAB, and the WaveFormRevealer graphical user interface is developed to obtain fast predictive waveform solutions for arbitrary combinations of sensor, structural properties, and damage. The predictive model is found capable of describing the nonlinear wave propagation phenomen...
107 citations
TL;DR: In this article, the concept of harvesting energy from galloping oscillations of a bluff body with different cross-section geometries attached to a cantilever beam was investigated, and the method to convert these oscillations into energy was proposed.
Abstract: The concept of harvesting energy from galloping oscillations of a bluff body with different cross-section geometries attached to a cantilever beam is investigated. To convert these oscillations int...
107 citations
TL;DR: In this paper, the authors used Lamb wave detection for detection of thin-walled structures due to their long propagation capability and sensitivity to a variety of different types of damage types.
Abstract: Lamb waves have shown great potentials in damage detection of thin-walled structures due to their long propagation capability and sensitivity to a variety of damage types. However, their practical ...
102 citations
TL;DR: The use of energy harvesting to provide power to low-power electronic devices has the potential to create autonomous, self-powered electronics as discussed by the authors, where the authors present the investigation of a novel ma...
Abstract: The use of energy harvesting to provide power to low-power electronic devices has the potential to create autonomous, self-powered electronics. This article presents the investigation of a novel ma...
92 citations
TL;DR: In this article, an effective analytical model which considers the effects of the electromechanical coupling and the nonlinear nonlinear magnetic field was proposed to design efficient low-frequency piezomagnetoelastic energy harvesters.
Abstract: In order to design efficient low-frequency piezomagnetoelastic energy harvesters, an effective analytical model which considers the effects of the electromechanical coupling and the nonlinear magne...
87 citations
TL;DR: In this article, a broadband magnet-induced dual-cantilever piezoelectric energy harvester is designed and developed, which consists of an outer and an inner beam with magn...
Abstract: In this article, a broadband magnet-induced dual-cantilever piezoelectric energy harvester is designed and developed. The dual-cantilever structure consists of an outer and an inner beams with magn...
TL;DR: Corrosion of steel reinforcement is one of the main causes of damage and premature failure of reinforced concrete structures, inflicting enormous costs for inspection, maintenance, restoration, and repair.
Abstract: Corrosion of steel reinforcement is one of the main causes of damage and premature failure of reinforced concrete structures, inflicting enormous costs for inspection, maintenance, restoration, and...
TL;DR: In this article, the energy efficiency of traditional McKibben muscle actuators is compared with hydraulic fluidic artificial actuators over full actuation cycles, and the performance of these muscle variants is compared by measuring blocked force and free contraction as a function of pressure, hysteresis, and energy efficiencies.
Abstract: In spite of extensive modeling and characterization efforts, little is known about the energetics of McKibben muscle actuators. This article experimentally investigates the effectiveness of traditional McKibben muscles at converting fluid energy delivered to the actuator to mechanical output work over full actuation cycles. Once these efficiency metrics are established, a comparison of the efficiencies of traditional pneumatic fluidic artificial muscles and hydraulic fluidic artificial muscles is presented. Two new hydraulic oil compatible bladder materials are tested—an elastomeric Viton bladder and an inelastic low-density polyethylene bladder. The performance of these muscle variants is compared by measuring blocked force and free contraction as a function of pressure, hysteresis, and energy efficiencies. The measurement of fluid volume delivered to the fluidic artificial muscles over their actuation ranges is shown to be useful for evaluating the accuracy of existing cylindrical volume models. Models ...
TL;DR: In this article, a nonlinear energy extraction interface achieved by synchronous mechanical switches is presented, where the complex switching control strategy is dodged by taking advantage of mechanical stoppers and the moving part of the piezoelectric oscillator, which is driven by the vibration itself.
Abstract: Nonlinear energy extraction techniques for piezoelectric vibration energy harvesting usually require synchronized electronic switches in their electronic interface circuits But the difficulty to self-power their complex switching control strategies limits their performances, especially in the presence of wideband ambient excitations This technical note presents a nonlinear energy extraction interface achieved by synchronous mechanical switches The complex switching control strategy is dodged by taking advantage of mechanical stoppers and the moving part of the piezoelectric oscillator, which is driven by the vibration itself As a result, the added mechanical stoppers and the self-synchronized nonlinear energy extraction circuit also make the energy harvesting device system be particularly suited to wideband ambient vibrations
TL;DR: In this paper, analytical and finite element electromechanical models that take into account the fact that the piezoelectric sheet does not cover the whole substrate beam are developed.
Abstract: Analytical and finite element electromechanical models that take into account the fact that the piezoelectric sheet does not cover the whole substrate beam are developed. A linear analysis of the a...
TL;DR: In this article, the authors explored a new paradigm through the employment of parametric resonance, which is not limited due to linear damping, therefore, the power output can potentially build up to higher levels.
Abstract: In the arena of vibration energy harvesting, the key technical challenges continue to be low power density and narrow operational frequency bandwidth. While the convention has relied upon the activation of the fundamental mode of resonance through direct excitation, this article explores a new paradigm through the employment of parametric resonance. Unlike the former, oscillatory amplitude growth is not limited due to linear damping. Therefore, the power output can potentially build up to higher levels. Additionally, it is the onset of non-linearity that eventually limits parametric resonance; hence, this approach can also potentially broaden the operating frequency range. Theoretical prediction and numerical modelling have suggested an order higher in oscillatory amplitude growth. An experimental macro-sized electromagnetic prototype (practical volume of ~1800 cm3) when driven into parametric resonance, has demonstrated around 50% increase in half power band and an order of magnitude higher peak power density normalised against input acceleration squared (293 mW cm23 m22 s4 with 171.5 mW at 0.57 m s22) in contrast to the same prototype directly driven at fundamental resonance (36.5 mW cm23 m22 s4 with 27.75 mW at 0.65 m s22). This figure suggests promising potentials while comparing with current state-of-the-art macro-sized counterparts, such as Perpetuum’s PMG-17 (119 mW cm23 m22 s4).
TL;DR: In this paper, the linear viscoelastic behavior of magnetorheological elastomers is analyzed according to their formulation and working conditions using a Physica MCR 501 rheometer from Anton Paar.
Abstract: The linear viscoelastic behaviour of magnetorheological elastomers is analysed in this work according to their formulation and working conditions. This study comprised both the synthesis of different magnetorheological elastomers and the strain and frequency sweep characterization under different magnetic fields and temperatures. The characterization was performed by a Physica MCR 501 rheometer from Anton Paar, equipped with a magnetorheologic cell 70/1T MRD. In the synthesis with a given elastomeric matrix, samples with different magnetic particle content are studied with two types of curing conditions: under the action of a magnetic field (anisotropic magnetorheological elastomers) and without a magnetic field (isotropic magnetorheological elastomers). The working conditions are excitation frequency, temperature and the applied external magnetic field. In this work, a new procedure to determine the linear viscoelastic behaviour is proposed; the loss factor is analysed in addition to analysing the storag...
TL;DR: In this article, a self-powered interface circuit for the optimized synchronous electric charge extraction technique applied to piezoelectric vibration energy harvesting is presented, where a peak detector circuit is developed to detect the maximum and minimum vibration displacements and drive the electronic switches synchronously.
Abstract: This article presents a self-powered interface circuit for the optimized synchronous electric charge extraction technique applied to piezoelectric vibration energy harvesting. A peak detector circuit is developed to detect the maximum and minimum vibration displacements and drive the electronic switches synchronously. This approach does not require additional piezoelectric elements to power the electronic interface itself for which a detailed analysis and a simple model are proposed to give a better understanding on the working principle. Finally, the influence of the switching phase lag and the peak detector power consumption on the harvested power is studied. Experimental studies are conducted and successfully compared with the theoretical approach.
TL;DR: It is shown from the simulation that the proposed nonlinear multiclass support vector machine–based approach is efficient and precise in quantitatively estimating damage statuses of the smart structures.
Abstract: In this article, a nonlinear multiclass support vector machine–based structural health monitoring system for smart structures is proposed. It is developed through the integration of a nonlinear multiclass support vector machine, discrete wavelet transforms, autoregressive models, and damage-sensitive features. The discrete wavelet transform is first applied to signals obtained from both healthy and damaged smart structures under random excitations, and it generates wavelet-filtered signal. It not only compresses lengthy data but also filters noise from the original data. Based on the wavelet-filtered signals, several wavelet-based autoregressive models are then constructed. Next, damage-sensitive features are extracted from the wavelet-based autoregressive coefficients and then the nonlinear multiclass support vector machine is trained by a variety of damage levels of wavelet-based autoregressive coefficient sets in an optimal method. The trained nonlinear multiclass support vector machine takes new test ...
TL;DR: In this article, a computational model was developed using finite element techniques within a continuum micromechanics framework to capture the effect of electron-hopping-induced conductive paths at t...
Abstract: In this study, a computational model is developed using finite-element techniques within a continuum micromechanics framework to capture the effect of electron-hopping-induced conductive paths at t...
TL;DR: Bistable piezoelectric generators have been demonstrated to outperform linear spring-mass-damper systems in terms of frequency bandwidth and harvested power from wideband vibrations as discussed by the authors.
Abstract: Bistable piezoelectric generators have been demonstrated to outperform linear spring–mass–damper systems in terms of frequency bandwidth and harvested power from wideband vibrations. In this work, ...
TL;DR: In this paper, the epoxy-based shape memory polymers were exposed to simulated γ-radiation environments up to 140 days for an accelerated irradiation, and the influence of the radiation on thermal and mechanical properties was evaluated by differential scanning calorimetry, dynamic mechanical analysis, and tensile test.
Abstract: In this article, the epoxy-based shape memory polymers were exposed to simulated γ-radiation environments up to 140 days for an accelerated irradiation. The influence of γ-radiation on thermal and mechanical properties was evaluated by differential scanning calorimetry, dynamic mechanical analysis, and tensile test. The glass transition temperatures (Tg) determined by differential scanning calorimetry and dynamic mechanical analysis decreased no more than 10%, and the shape recovery speed became a little faster after γ-radiation of 1 × 105 Gy. The tensile strength and elastic modulus could, respectively, maintain 26 MPa and 1.36 GPa after being irradiated by 1 × 106 Gy radiation, showing great potential in aerospace structural materials.
TL;DR: In this article, a new acceleration sensor using flexoelectric barium strontium titanate cantilever was designed, fabricated, and tested for vibration monitoring, which was configured as a trapezoidal unimorph with a barium stoneme titanate layer bonded onto a steel substrate.
Abstract: In this article a new acceleration sensor using flexoelectric barium strontium titanate cantilever was designed, fabricated, and tested for vibration monitoring. The flexoelectric sensors were configured as a trapezoidal unimorph with a barium strontium titanate layer bonded onto a steel substrate. Seismic mass was attached to the unimorph tip to amplify the transverse flexoelectric response of the barium strontium titanate layer. The theoretical model was developed and validated by vibration tests using the prototyped flexoelectric unimorph. The prototyped accelerometer with thickness of 0.1 mm and length and width in millimeters showed a stable sensitivity of 0.84 pC/g over the frequency range of 100 Hz–1.6 kHz. The aging property of the flexoelectric material was demonstrated to be much better than that of the reported piezoelectric materials right after poling. Scaling effect analysis was also performed for flexoelectric unimorphs. The test results and initial scaling effect analysis indicate that mic...
TL;DR: In this paper, structural health monitoring has become a viable solution to monitor critical infrastructure components that show distress or are unable to pass current load ratings, and the authors introduce the c...
Abstract: Structural health monitoring has become a viable solution to monitor critical infrastructure components that show distress or are unable to pass current load ratings. This research introduces the c...
TL;DR: In this article, the authors show that polyurethanes have certain advantages over other electroactive polymer materials, such as higher permittivity and higher dielectric breakdown strength, which enable the industrial development of highly efficient and environmentally sustainable energy converters, which opens up the possibility to further exploit large renewable and inexhaustible energy sources like wind and water that are widely unused otherwise.
Abstract: Electroactive polymers are soft capacitors made of thin elastic and electrically insulating films coated with compliant electrodes offering a large amount of deformation. They can either be used as actuators by applying an electric charge or used as energy converters based on the electrostatic principle. These unique properties enable the industrial development of highly efficient and environmentally sustainable energy converters, which opens up the possibility to further exploit large renewable and inexhaustible energy sources like wind and water that are widely unused otherwise. Compared to other electroactive polymer materials, polyurethanes have certain advantages over silicones and acrylates. Due to the inherently higher permittivity as well as the higher dielectric breakdown strength, the overall specific energy, a measure for the energy gain, is better by at least factor of 10, that is, more than 10 times the energy can be gained out of the same amount of material. In order to reduce conduction los...
TL;DR: In this article, the authors examined the piezoelectric-based energy harvesting on civil infrastructures and adopted four concrete slab-on-gird harvesters considering their wide usage.
Abstract: This article examines the piezoelectric-based energy harvesting on civil infrastructures. Piezoelectric cantilever–based harvesters are adopted considering their wide usage. Four concrete slab-on-g...
TL;DR: In this paper, a shear-mode semi-active dynamic vibration absorber based on magnetorheological elastomers is proposed, and the dynamic design principle of an axial semiactive dynamic vibrator attached to ship shafting is studied.
Abstract: Magnetorheological elastomers are a new kind of magnetorheological materials mainly composed of polymer rubber and micro-sized magnetizable iron particles. Dynamic vibration absorbers based on magnetorheological elastomers are widely used in vibration systems with small amplitude since they have the advantages of no sealing equipments, good stability, and rapid response. In this article, a shear-mode semi-active dynamic vibration absorber based on magnetorheological elastomers is proposed, and the dynamic design principle of an axial semi-active dynamic vibration absorber attached to ship shafting is studied. The material preparation of magnetorheological elastomers and their properties under different magnetic fields are discussed. The structure of a single semi-active dynamic vibration absorber is designed, and theoretical analysis of shift-frequency property of a single semi-active dynamic vibration absorber is also investigated. The magnetic flux density of magnetorheological elastomers in the semi-ac...
TL;DR: In this article, superharmonic dynamics are characteristic of many nonlinear systems undergoing high levels of excitation, however, what constitutes high levels is relative to the system under study.
Abstract: Superharmonic dynamics are characteristic of many nonlinear systems undergoing high levels of excitation. However, what constitutes high levels is relative to the system under study. For instance, ...
TL;DR: In this article, an analysis of a new energy harvesting model is presented, based on a simple portal frame structure, considered a nonideal system due to the kind of excitation influenced by the response of the system, such as a direct current motor with limited power supply.
Abstract: An analysis of a new energy harvester model is presented, based on a simple portal frame structure, considered a nonideal system due to the kind of excitation influenced by the response of the system, such as a direct current motor with limited power supply. The horizontal motion of the portal frame is considered under a nonideal excitation, and the approximated mathematical model of the system is obtained, considering the coupled oscillators. To model the piezoelectric coupling, the nonlinearities of the piezoelectric material were considered. A constantly sustained energy harvesting is essential for using these devices in real applications; for this, a control strategy is required. Passive control was obtained by means of a nonlinear substructure with properties of nonlinear energy sink. Numerical simulations were performed in order to find best values of control parameters. To check the robustness of the control strategy, an analysis considering uncertainties in the parameters of the model was performe...
TL;DR: The design, manufacturing, and parametric modeling of a curved cellular structure (SILICOMB) with zero Poisson’s ratio produced using Kirigami techniques from polyetheretherketone films is described, showing a high degree of tailoring that these cellular structures could offer in terms of minimum relative density and maximum stiffness.
Abstract: The work describes the design, manufacturing, and parametric modeling of a curved cellular structure (SILICOMB) with zero Poisson’s ratio produced using Kirigami techniques from polyetheretherketon...