Piezoelectric Fiber Composites Research Articles

Comparative Performance Analysis of Inverse Phase Active Vibration Cancellation Using Macro Fiber Composite (MFC) and Vibration Absorption of Silicone Gel for Vibration Reduction.

This study focuses on addressing the issue of unwanted vibrations commonly encountered in various fields by designing an Active Vibration Cancellation (AVC) structure using a flexible piezoelectric composite material macro fiber composite (MFC). A comparative performance analysis was conducted between the AVC and a traditional passive gel that continuously absorbs vibrations. The results showed that AVC was more effective in mitigating vibrations, making it a promising solution for vibration control. The results of this study from extensive vibration-sensing experiments and comparisons revealed that AVC effectively cancels the vibrations and vibration absorption performance of the passive gel. These findings underline the potential of AVC as an efficient method for eliminating and managing undesired vibrations in practical applications. Specifically, AVC demonstrated a high vibration cancellation ratio of approximately 0.96 at frequencies above 10 Hz. In contrast, passive gel exhibited a relatively consistent vibration absorption ratio, approximately 0.70 to 0.75 at all tested frequencies. These quantitative findings emphasize the superior performance of AVC in reducing vibrations to levels below a certain threshold, demonstrating its efficacy for vibration control in real-world scenarios.

FIV and energy harvesting using bluff body piezoelectric water energy harvester with different cross-sections

Research utilizing piezoelectric fiber composites to power network nodes or micro-sensors by capturing energy from the surrounding environment is becoming a hot spot, and the structural design to efficiently improve the performance of energy harvesting is very important. The performance of a vertical cantilever piezoelectric water energy harvester (PWEH) with three different cross-sections including circular, square and equilateral triangle, each with a mass ratio of 4.8, was investigated at Reynolds number within 770–8800. Emphasis is placed on the effects of the bluff body cross-section, load resistance, and flow velocity on the flow-induced vibration (FIV) and energy response of the vertical cantilever beam of the PWEH. Except for the decreasing amplitude in the lower branch of the circular cylinder water energy harvester (CWEH), there is no distinction in the vibration response branches compared to the classical elastically supported circular cylinder. The resistance has little effect on the vibration response, while it has a significant effect on the voltage and power response. The maximum amplitude and pendulum angle of the square cylinder water energy harvester (SWEH) are slightly larger than those of the CWEH. The maximum voltage and power are smaller for the SWEH than for the CWEH. The equilateral triangular cylinder water energy harvester (TWEH) demonstrates excellent performance. It has a maximum amplitude of 3.8 D, 3.4 times that of the CWEH. The peak pendulum angle of TWCH is 13.9°, 3.2 times that of CWEH. It has a voltage of 0.057 V at a resistance of ∞, which is 3.4 times that of CEWH. In addition, the TWCH has an output power of 0.38 nW at a resistance of 106Ω, which is 9.5 times that of the CWEH. This study suggests that the best energy efficiency of TWEH is achieved by coupling vortex-induced vibration (VIV) and galloping excitation.

Numerical framework for anisotropic flexible piezoelectrics with large deformation

Flexible piezoelectric materials with high stretchability have been realized in industrialization production. Among them, piezoelectric fiber composites made of elastomers and piezoelectric polymers have gained widespread attentions in smart applications. In general, piezoelectric fiber composites can be considered as anisotropic materials. However, most existing piezoelectric constitutive models, especially those integrated into commercial software, only account for small deformation conditions, which are not suitable for anisotropic flexible piezoelectrics. In the present work, a novel model for anisotropic flexible piezoelectric material is established based on the anisotropic Neo-Hookean material model and electromechanical theory. The finite element framework is implemented in the commercial finite element software ABAQUS via a user element subroutine, with a monolithic algorithm procedure employed to solve the nonlinear governing equations. To validate the accuracy of finite element implementation, analytical solutions for equibiaxial stretching of transversely isotropic piezoelectric have been compared with simulated results. Furthermore, the influences of anisotropy level on electromechanical response are also discussed. Subsequently, numerical simulations of bending actuators and sensors further demonstrate the robustness of the developed elements. The obtained results show that the anisotropy direction and level have both favorable and unfavorable influences on structure performances, which could provide a reference for the design of anisotropic flexible piezoelectric structures.

Dynamic analysis of graphene-reinforced sandwich plates with piezoelectric macro fiber composite face sheets

Graphene is considered as an ideal candidate for composite materials owing to the outstanding physical characteristics. However, existing higher-order shear deformation theories in the literature may meet severe challenges for the accurate prediction of natural frequencies of graphene-reinforced sandwich plates with piezoelectric macro fiber composite (MFC) face sheets. If transverse shear deformations cannot be described accurately, the dynamic behaviors of piezoelectric sandwich plates with graphene reinforcements will be significantly impacted by the large differences of material properties at interfaces of adjacent layers and electro-mechanical coupling characteristic. Thereby, a novel electro-mechanical coupling theory is to be proposed for the free vibration of graphene-reinforced sandwich plates with MFC face sheets. Based on the Reissner mixed variational theorem (RMVT), the precision of the interlaminar shear stresses including the electro-mechanical coupling effect can be improved. The modified interlaminar shear stress field is absorbed in the strain energy, which can enhance the accuracy of the free vibration response of piezoelectric sandwich plates. Additionally, the second-order derivatives of in-plane displacements have been eliminated from the interlaminar shear stress components, which can substantially simplify the finite element implementation. Thus, a simple C0-type finite element formulation is developed for the free vibration of piezoelectric sandwich plates with graphene reinforcements. The 3D elasticity solutions and the results obtained from other theories are used to evaluate the performance of the proposed theory. In comparison with the existing higher-order theories, the proposed theory can produce more accurate results. In addition, a comprehensive parametric study is conducted to explore the impacts of significant parameters on the free vibration behaviors of piezoelectric graphene-reinforced sandwich plates.

Selection of piezoeloectric material and fiber volume fraction to maximize the electrical power produced by macro-fiber composite energy harvesters

A piezoelectric Macro fiber composite (MFC) materials developed in the last decade found widespread applications such as vibration sensing, actuation and structural health monitoring. Unlike conventional ceramic piezoelectric materials (PZT), these composites show many advantages such as flexibility, reliability and high actuation capacity. However, increasing their energy harvesting capabilities still remains a challenge. Modeling and simulation of electrical energy harvesters using MFC patches provide a mean for geometrical optimization and appropriate choice of the MFC composite. This paper proposes a linear analytical model for prediction of the electro-mechanical response of bimorph harvesters using MFC patches. Homogenization technique is used to describe the equivalent piezoelectric properties of the composite structure of the MFC patch. This paper investigates the effect of the volume fraction of the fibers and the material choice of the piezoelectric fibers and epoxy matrix on the generated electrical power. It has been found that an increased fiber volume fraction causes a decrease of the voltage, the power and the velocity amplitudes for a range of load resistance. However, an increase in the fiber volume fraction FVF is achieved by an increase of the current amplitude for a range of load resistance. Maximum amount of power is generated by the bimorph MFC harvester for an FVF of 86% which corresponds to the reference configuration. The piezoelectric fiber material has a significant influence on the output power. In fact, the SONOX-P502 generated the greatest electrical power. However, the material of the matrix has a negligible effect on the generated power.

Optimisation of active SHM system based on optimal number and placement of piezoelectric transducers

This paper concerns optimal placement and number of discrete piezoelectric macro fibre composite (MFC) sensors to optimise SHM systems. Its novelty lies in a two-stage placement methodology for discrete piezoelectric transducers, with fitness and objective functions to optimise the location and number of discrete piezoelectric sensors in order to reduce the cost and complexity of data processing and increase the effectiveness in damage detection. The maximisation of sensor voltage amplitude at multiple modes of vibration and the average of sensor normal damage index [Formula: see text] measured for several plates artificially cracked at different positions and orientations are proposed as objective functions to optimise the locations and the number of efficient piezoelectric sensors. A non-normalised root-mean-square deviation [Formula: see text] is introduced in this study in place of the conventional normalised [Formula: see text] to assess the degree of damage and sensor effectiveness. Furthermore, normal damage indices [Formula: see text] and [Formula: see text] normalised to 100% are proposed as the fitness functions. The placement methodology is utilised and verified for stiffened and unstiffened plates; stiffeners are used to break the dynamic symmetry and increase plate complexity. The performance of the placement methodology is tested for a healthy and 12 damaged plates to optimise SHM system based on the maximisation of sensor voltage and average normal damage index [Formula: see text] as objective functions. The results show that the placement methodology is efficient in determining the optimum number and placement of piezoelectric sensors at a low computational effort. The optimum placement of two piezoelectric sensors can efficiently monitor the crack’s initiation at different positions and multiple modes of vibration. The optimal placement and number of sensors have a positive impact on the cost, data acquisition and processing of the active SHM system

Ultrasonic-based tensile force estimation for cylindrical rod at various temperature conditions

This study presents the development of a tensile force estimation technique based on the ultrasonic bulk wave for cylindrical rod in a suspension bridge anchor system. Three piezoelectric macro fiber composites (MFC) transducers are installed on the surface of a cylindrical rod specimen for the generation and sensing of ultrasonic bulk waves. Ultrasonic responses are obtained at various tensile force levels and temperature conditions, and the relationship between the time lag of the ultrasonic response and the tensile force is established. In particular, the temperature effect on the tensile force estimation is theoretically derived and compensated for field applications. The originality of this study includes (1) theoretical derivation and investigation of the relationship between an applied tensile force level and the time lag of an ultrasonic response considering the variations of temperature, density, and elastic modulus, (2) development of a tensile force estimation and temperature compensation technique without temperature measurement, and (3) application to the tensile force estimation of the rod structure commonly used in a suspension bridge anchor system. The performance of the developed tensile force estimation technique was examined based on mock-up experiments of the rod structure of a real suspension bridge anchor system.

Lightweight Piezoelectric Bending Beam-Based Energy Harvester for Capturing Energy From Human Knee Motion

Harvesting energy from the human body has attracted substantial attention from industries and academics as it is a promising solution to address the battery life issue. In this article, we developed a bimorph piezoelectric bending beam-based energy harvester to scavenge energy from the human knee motion for powering body-worn electronics such as smartwatches and health monitors. During walking, the human knee will flex and extend to periodically deform piezoelectric macro fiber composites (MFC) bounded to the bending beam, thus generating electricity. The mathematical models of the whole system including the model of the large deflection of the bending beam, movement analysis of the end of the bending beam (slider-crank mechanism), the model of piezoelectric transducers, and measurement of the human knee angle are developed to comprehensively study the harvester. To validate the presented mathematical models, experimental testing on a human body when the subject walks on a treadmill at three different walking speeds is conducted here. The experimental results show good agreement with the simulation results, which indicates that the developed models can characterize the harvester. In addition, the performance of the harvester walking in different contexts is also evaluated. The average power can reach 12.79 mW for level-ground walking, 9.91 mW for stair descending, and 7.70 mW for stair ascending, when walking at a self-selected speed.

Multi-Mode Shape Control of Active Compliant Aerospace Structures Using Anisotropic Piezocomposite Materials in Antisymmetric Bimorph Configuration

The mission performance of future advanced aerospace structures can be synthetically improved via active shape control utilizing piezoelectric materials. Multiple work modes are required. Bending/twisting mode control receives special attention for many classic aerospace structures, such as active reflector systems, active blades, and compliant morphing wings. Piezoelectric fiber composite (Piezocomposite) material features in-plane anisotropic actuation, which is very suitable for multiple work modes. In this study, two identical macro-fiber composite (MFC) actuators of the F1 type were bonded to the base plate structure in an “antisymmetric angle-ply bimorph configuration” in order to achieve independent bending/twisting shape control. In terms of the finite element model and homogenization strategy, the locations of bimorph MFCs were determined by considering the effect of trade-off control capabilities on the bending and twisting shapes. The modal characteristics were investigated via both experimental and theoretical approaches. The experimental tests implied that the shape control accuracy was heavily reduced due to various uncertainties and nonlinearities, including hysteresis and the creep effect of the actuators, model errors, and external disturbances. A multi-mode feedback control law was designed and the experimental tests indicated that synthetic (independent and coupled) bending/twisting deformations were achieved with improved shape accuracy. This study provides a feasible multi-mode shape control approach with high surface accuracy, especially by employing piezocomposite materials.

Porous, multi-layered piezoelectric composites based on highly oriented PZT/PVDF electrospinning fibers for high-performance piezoelectric nanogenerators

Piezoelectric nanogenerators (PENGs) that can harvest mechanical energy from ambient environment have broad prospects for multi-functional applications. Here, multi-layered piezoelectric composites with a porous structure based on highly oriented Pb(Zr0.52Ti0.48)O3/PVDF (PZT/PVDF) electrospinning fibers are prepared via a laminating method to construct high-performance PENGs. PZT particles as piezoelectric reinforcing phases are embedded in PVDF fibers and facilitate the formation of polar β phase in PVDF. The multi-layered, porous structure effectively promotes the overall polarization and surface bound charge density, resulting in a highly efficient electromechanical conversion. The PENG based on 10 wt% PZT/PVDF composite fibers with a 220 µm film thickness outputs an optimal voltage of 62.0 V and a power of 136.9 µW, which are 3.4 and 6.5 times those of 10 wt% PZT/PVDF casting film-based PENG, respectively. Importantly, the PENG shows a high sensitivity of 12.4 V·N−1, presenting a significant advantage in comparison to PENGs with other porous structures. In addition, the composites show excellent flexibility with a Young’s modulus of 227.2 MPa and an elongation of 262.3%. This study shows a great potential application of piezoelectric fiber composites in flexible energy harvesting devices.

Extended Locally Exact Homogenization Theory for Effective Coefficients and Localized Responses of Piezoelectric Composites

Herein, the elasticity‐based locally exact homogenization theory (LEHT) is extended to study the effective and localized responses of piezoelectric fiber composites. Based on the Trefftz concept, coupled internal solutions for electric fields and elastic displacements are developed for repeating unit cells (RUCs) that are characterized from the composite domain. The unknown coefficients of the internal fields can be determined by imposing interfacial continuity conditions between fiber and matrix and implementing the newly proposed multiphysics periodic boundary conditions. Finally, the generalized constitutive relations are established to predict the effective coefficients. The accuracy of the proposed technique is tested by validating the present simulations against the analytical Eshelby solution and asymptotic method, classical Mori−Tanaka (M−T) model, finite element (FE)‐ and finite volume (FV)‐based methods, as well as the experimental measurement in the literature with excellent agreement. What is more, several microstructural effects, such as phase volume fraction, fiber arrangement, etc., are varied to test their effects on the piezoelectric composites at both homogenized and localized levels. Based on the presented computational efficiency, the multiphysics LEHT is encapsulated into a blackbox with input/output data constructions for easy implementation by professionals or nonprofessionals.

Piezoelectric fiber composites with polydopamine interfacial layer for self-powered wearable biomonitoring

Doping polymers with ceramic nanofillers is a widely-adopted routine for developing high-performance nanocomposites. However, improving the interaction between the nanofillers and the polymer matrix for an enhanced composite performance remains highly desired in the community. Herein, we systematically investigated the barium titanate doped polyvinylidene fluoride (BTO/PVDF) piezoelectric nanocomposites in a fiber form through comprehensive phase-field simulation and detailed experimental characterization. Both experimental and theoretical results indicated that the introduction of 2.15 vol% polydopamine (PDA) coating on the BTO nanoparticles could remarkably promote the local all-trans conformation and modulus match at the nanofillers-polymer interface, giving rise to the maximum piezoelectric charge coefficient and piezoelectric voltage coefficient as well as mechanical stiffness. To demonstrate the effectiveness of the PDA modification, a polydopamine modified nonwoven piezoelectric (PMNP) textile was constructed based on the composite fiber, which showed outstanding sensitivity and long-term stability for wearable biomonitoring, including limb motion detection, facial expression identification, respiratory monitoring, and human-machine interfacing. This work endows insight into the fundamental mechanism of the interfacial coupling effect in polymer composites for the development of high-performance wearable textile bioelectronics. • Polydopamine modified nonwoven piezoelectric (PMNP) textile was developed. • The mechanism was studied via phase-field simulation and detailed characterization. • 2.15 vol% PDA coating maximizes the piezoelectric coefficient and β phase content. • Facial emotion identification and human-machine interaction was enabled by PMNPs.

Ultra-magnetic field sensitive magnetoelectric composite with sub-pT detection limit at low frequency enabled by flash photon annealing

An ultra-sensitive magnetic field detector is demonstrated in a bilayer magnetoelectric (ME) composite structure employing a flash photon annealing (FPA) treated amorphous Metglas (FeBSi) alloy and piezoelectric single crystal macro fiber composites (SFC). A millisecond FPA annealing approach altered the magnetostrictive and mechanical properties of Metglas by annealing at a high temperature without inducing severe embrittlement. The ME composite (MEC) fabricated with FPA-treated Metglas (FPA-MEC) exhibited an enhanced ME coupling coefficient (at a resonance condition ~47% and at an off-resonance condition ~52%) relative to that of untreated Metglas based ME composite (pristine MEC), owing to the improved magnetic flux concentration/piezo-magnetic coefficient and reduced resonance loss in Metglas. This led to the realization of an ultra-sensitive magnetic field sensor with a direct detection limit of 0.5 pT [1 order improved performance compared to the pristine MEC (sensing limit of 5 pT)] at an extremely low resonance frequency condition (<100 Hz). The obtained results demonstrate a feasible way to design magnetic sensors for detecting bio-magnetic and extremely low-frequency (ELF) magnetic fields under ambient conditions.

Vibration damping of aircraft propeller blades using shunted piezoelectric transducers

Gas turbine engine blades experience vibrations due to the flow disturbances, these vibrations are critical to the engine durability and performance. Piezoelectric transducers (sensors and actuators) have been used for engine blade vibrations damping either through a passive or active vibration control. The propeller blades are part of turboprop engine and considered as one of the main source of turboprop engine vibrations. Piezoelectric blade damping ideas have been studied by other researchers for fan blades and compressor blades. In this research a vibration damping procedure using piezoelectric transducers applied to an unmanned aerial vehicle (UAV) composite propeller. Experimental investigation introduces an approach for the propeller vibration damping using piezoelectric transducers in conjunction with appropriate shunt circuit. Three thin piezoelectric transducers macro fiber composite (MFC) type PZT-5A are surface-mounted on the propeller, one at each blade. These transducers are placed at locations of high modal strain areas for the propeller first mode at each blade, where these locations are identified by finite element numerical simulation. Electronic resonance shunt circuit, resistor-inductor-capacitor type, for the piezoelectric transducers is designed and experimentally developed such that effective vibration suppression of the propeller is achieved. The experimental and numerical investigations in this research illustrate that piezoelectric transducers with appropriate shunt circuit reduces the aircraft propeller vibrations.

Fine scale 2-2 connectivity PZT/epoxy piezoelectric fiber composite for high frequency ultrasonic application

High frequency piezoelectric fiber composites have extensive application in fields of biomedical imaging, ultrasonic inspection, underwater acoustic imaging and so forth. In this paper, fine scale 2-2 connectivity PZT/epoxy piezoelectric fiber composites were tailored by using the dicing-filling-pressing method with poled ferroelectric ceramic (PZT) and epoxy resin, respectively. The effects of thickness and volume fraction of PZT ceramic on piezoelectric, dielectric, and acoustic properties of the composites were discussed. The results showed that the piezoelectric strain constant, relative permittivity (ε33T), thickness electromechanical coupling coefficient (kt), mechanical quality factor (Qm) and acoustic impedance of the composites exhibit an increasing trend with the increase of the volume fraction of the PZT ceramics, while the piezoelectric voltage constant (g33) showed a decreasing trend. In the low frequency range of 60−90 kHz, the planar resonance peaks can be observed in the impedance-frequency spectra, while in the high frequency range of 2−6 MHz, there only exist clear thickness resonance peaks. With increasing the PZT volume fraction, the bandwidth of the thickness vibration mode of the piezoelectric fiber composites under the same thickness increases gradually. When the PZT volume fraction keep unchanged, the thickness resonance frequency of the composites increases with decreasing the thickness as well as the bandwidth of the thickness vibration mode, which is conducive for improving the frequency response range of the ultrasonic transducer made of the proposed piezoelectric fiber composites.

Efficient excitation of transverse vibrational modes using improved configurations of PFCs connected to an isotropic plate

In this work, we investigate efficient excitations of transverse (out-of-plane) vibrations of isotropic rectangular plates using piezoelectric fiber composites (PFCs) by experimental measurement. Four PFCs are separately bonded on a rectangular plate with four configured electrode connections to excite transverse vibration of the plate. The proposed configurations of the PFCs, including placements and electrode connections, are inspired by efficient transverse excitations of piezoelectric rectangular plates, whose mode shapes can be divided into four groups and whose electromechanical coupling efficiency can be largely improved by designs of partial electrodes. To visually demonstrate the excitation efficiency, an amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI) measurement technique is set up to obtain full-field transverse mode shapes. Other than AF-ESPI, a laser Doppler vibrometer (LDV) displacement sensing system is employed to investigate the excitation performances of the PFCs according to resonant frequencies with emphasis on the influences of the measured nodal lines of the plate. The experimental results presented in this study indicate that the excitation efficiency of the transverse vibrations in flexible structures can be improved by bonding distributed PFCs with configured electrode connections. In addition, we show that the vibrations of isotropic rectangular plates can be related to those of piezoelectric rectangular plates, from the experimental modal excitation point of view.

An electromechanical cohesive zone model merging with contact and friction effects for fiber debonding and pushing-out in piezoelectric fiber composites

Owing to electromechanical coupling of piezoelectric fiber composites, they have been widely used in sensing and active control of aeronautic and aerospace structures. In order to describe the interface fracture of piezoelectric fiber composites, a micromechanically motivated interface model based on a cohesive zone model is developed, and it is closer to the actual debonding process including contact and friction effects. In this study, the proposed interface model is formed through incorporating contact effect and a Coulomb friction law into a bilinear traction-separation law, and the electromechanical relationships across separated and contacted crack surfaces are provided. And for purpose of analyzing single piezoelectric fiber debonding, an axisymmetric model and its double series solution are adopted. Comparing with existing experiment and simulation results, the proposed model takes the friction related to the normal pressure varying with the gap between crack surfaces into account, and it is able to qualitatively capture salient features of the experimental record, and guarantee a smooth transition from cohesive debonding to frictional sliding. Furthermore, the piezoelectric fiber push-out behavior is investigated including initial perfect bonded, partial debonding with interface softening and frictional sliding after complete debonding. The dependences of different parameters, such as fiber radius, fiber length, electric field and interface properties, on the load-displacement curve and the responses around piezoelectric fiber are also investigated. It can be revealed that piezoelectric fibers can be designed to monitor and tailor the fracture behavior of composites.

Mechanical Properties and Wind Energy Harvesting Characteristics of PZT-Based Piezoelectric Ceramic Fiber Composites

Mechanical Properties and Wind Energy Harvesting Characteristics of PZT-Based Piezoelectric Ceramic Fiber Composites

Modeling and simulating the effects of a general imperfect interface in fibrous piezoelectric composites

Interfacial behavior within fibrous piezoelectric composites (PZCs) may dramatically degrade the overall electromechanical performance and simultaneously vary the effective coupling moduli of these intelligent materials. In the present paper, we first recapitulate a physics-based general interfacial relation, which is rigorously derived from an ideal three-phase configuration and thus owns explicit physical meaning, to characterize this behavior between two different piezoelectric media. Afterwards, the explicit strong and weak governing equations of fibrous PZC boundary value problems (BVPs) are constructed, and a computational approach is then developed with the help of the extended finite element method (XFEM) to account for the discontinuities within both the primary (i.e., the electric potential and displacement fields) and the secondary fields (i.e., the normal electric displacement and normal traction fields). To achieve a benchmark problem with analytical exact solution, a simplified general interfacial relation is introduced, and a fibrous PZC BVP involving a cylindrical simplified general interface is designated and analytically solved. Hereafter, the convergence performance and validity of the elaborated computational approach are tested in detail. Eventually, discussions are further made on the influence of material composition and inhomogeneity shapes on the electroelastic coupling behavior of PZCs, and a few concluding remarks are drawn.

Uncertainty quantification and global sensitivity analysis of piezoelectric energy harvesting using macro fiber composites

Piezoelectric macro fiber composites (MFCs) are widely used for energy harvesting due to their flexibility and high electromechanical conversion efficiency. In previous research studies, numerical and analytical models have been developed for MFC-harvesters using homogenized electromechanical properties. In this paper, an analytical electroelastic coupled model, based on the mixing rules, is used to predict the output responses of an MFC-harvester coupled in 33-mode of the PZT fibers. The predicted responses exhibit variation because of the uncertainty of the parameters used in the proposed model. The research reported in this paper aims to estimate the effect of the uncertainty in the physical properties of both piezoelectric fibers and epoxy matrix on the model responses and to identify the parameters which cause large output variability. The uncertainties of the parameters are defined as the variability bounds based on the tolerances reported by the manufacturers. Global sensitivity analysis (GSA) is an appropriate method to study the effect of the uncertainty of parameters on the electromechanical response of the harvester. Two GSA are applied in this paper: (i) the Morris method based on the elementary effects measures and (ii) the variance method which consists in computing the Sobol’ indices, whose goal is to identify systems parameters which have significant impact on the voltage and the power outputs of a bimorph MFC-harvester. This study leads to a qualitative comparison between the two methods which are strategically different. Both methods indicate that the elastic modulus and the density of the piezoelectric fibers, the length and the thickness of the representative volume element of the MFC-patch are the most influential parameters that affect the output voltage. It has also been shown that the order of importance of the parameters can change from the short-circuit to the open-circuit condition. Furthermore, Monte Carlo simulations are used to propagate the uncertainties of the parameters in order to determine the envelope of the variability of the responses. This study reveals the importance of considering model parameter uncertainties in the development of robust prediction tools for piezoelectric energy harvesting devices.