Bimorph Cantilever Research Articles

Design of Shape Memory Micro-Actuator Modules with Sequential Actuation

Shape memory alloy film-based micro-actuators have their behaviour controlled by a change in the thermomechanical stress that occurs in the bimorph - shape memory alloy film plus substrate assembly. The modification of the composition of the shape memory alloy leads to a change of the transformation temperature and implicitly of the temperature at which the stress change takes place in the bimorph. The design of micro-actuator blocks in which the composition and/or the temperature control mode of each micro-actuator in the block allows to obtain successive or sequential transformation sequences. The paper analyses the case of cantilever actuator modules with films of different compositions, deposited on the same substrate. It is highlighted how the composition of the alloy film with shape memory influences the modification of the curvature of bimorph cantilever type actuators in the studied block.

Generation of energy in console piezoelectric energy harvesters

Energy harvesting of mechanical vibrations and their conversion into electrical energy using piezoelectric devices has become widespread. This has been made possible by the creation of high-energy piezoelectric materials and the proliferation of miniature devices with a few milliwatts of power.
 In this work, the oscillations of the rod cantilever bimorph energy harvester under harmonic loads are investigated. A two-layer rod consisting of a brass base and a rectangular piezoelectric element with electroded flat surfaces without and with tip mass is considered. The thickness of the layers is much less than the width and the width is much less than the length, which allows us to use the hypothesis of flat sections and assumptions of the potential difference linearity by thickness of the element, as well as beams bending relations.
 There is derived the characteristic equation for beam bending oscillations, the wave numbers, circular frequencies and natural frequencies are determined. There is carried out The averaging of material characteristics over the cross-sectional area. Eigenforms of oscillations are constructed, the dependence of natural frequencies from body size and tip mass is analyzed.
 The next step is to study the forced oscillations of the energy harvesters with tip mass at the end at given oscillations of the base. The equation of the elastic line of the console is formed, the maximum deflections and angles of rotation are determined. The voltage generated on the piezo element plates is determined taking into account the electrical resistance. Due to the voltage and resistance of the conduct line the power of the energy harvester is determined. Curves of voltage and power dependence from load frequency and external resistance are constructed. It is established that the voltage and power of the element change in proportion to R. The maximum power of the energy collector occurs in the vicinity of resonances, and before the first resonance the power is almost zero. Between the first and second resonance, the power is approximately 1,5 mW. During the transition to the ultrasonic zone, the power of the energy collector increases significantly.Analysis of the harvester operation at resonant frequencies requires consideration of the damping of oscillations in the material.

Uniform Stress Distribution of Bimorph by Arc Mechanical Stopper for Maximum Piezoelectric Vibration Energy Harvesting

To convert as much vibration energy as possible into electrical energy, the design of a high-performance piezoelectric vibration energy harvester (PVEH) has been studied widely in recent years. To overcome the low energy utilization of a traditional piezoelectric cantilever by inhomogeneous strain, a uniform stress distribution of bimorph by an ARC mechanical stopper structure has been designed for maximum piezoelectric vibration energy harvesting. Deflection equations and their simulation at the first-order modal of two classic bimorph cantilever beam models, with transverse tip force and with equal curvature, are derived based on the Euler–Bernoulli beam assumption. Piezoelectric energy from a beam model with equal curvature is four times that of a cantilever beam model with transverse tip force at the theoretical level. The nonlinear frequency response performance of bimorphs by an ARC mechanical stopper and point stopper model could be observed by the numerical simulations of the lumped parameter electromechanical model. PVEH prototypes were manufactured by 3D printing and tested. To verify the high-power generation capacity, PVEH with an ARC stopper has 1.756 times more voltage than that of a PVEH with a point stopper.

Piezoelectric Transducer as an Energy Harvester: A Review

Over the years, energy harvesting technologies have been used in various self-powered systems. These technologies have several methods of application depending on their usage. Renewable energy is one of the types of energy harvesting technologies where energy is generated from naturally replenished sources. One of the energy harvesting methods that is commonly used is piezoelectric transducers. Piezoelectric materials are groups of elements that can be used to generate electricity when mechanical energy is applied. When external mechanical stress is applied, the inner lattice is deformed, resulting in the separation of the positive and negative centers of the molecule and thus the generation of a small dipole. Therefore, this paper aims to discuss the output of the piezoelectric transducer by reviewing it depending on two different material types and in other energy harvesting structures. Furthermore, a comparison was made in order to compare the power output of the two materials. Similarly, the most used piezoelectric transducer structures for power harvesting applications were revised. In addition, the parameters that affect the value of the generated power output were discussed using the figures of merit (FOM) concept. Moreover, the according to the FOM concepts, when stress is applied, the electrical energy extracted from a piezoelectric energy harvesting material is determined by the change in stored electrical energy within a piezoelectric material. The figures of merit (FOM) depend on the piezoelectric strain and its permittivity. The piezoelectric strain directly relates to FOM, while the permittivity has an inverse relationship with FOM. Thus, the highest strain constant and low permittivity material will provide the highest energy output. Additionally, lead-based (PZT) material has a strain coefficient d33 equal to 390 Coul/Nx10-12, and permittivity value ranging from 1000 to 3500 and can generate power output that is equal to 52mW at 100Hz, which is higher than the output of the lead-free-based material Barium Titanate (BaTiO3). The output of piezoelectric also depends on the piezoelectric transducer’s structure. The circular diaphragm’s power output is greater than the bimorph cantilever’s power output due to the presence of a proof mass in the center of the diaphragm that provides prestress to the piezoelectric which improves the low-frequency performance of the energy harvester.

Piezoelectric unimorph and bimorph cantilever configurations: Design guidelines and strain assessment

Multi-stable configurations of piezoelectric harvester are quite successful in achieving the two important goals, the broadband frequency response and large orbit oscillations exhibiting periodic, multi-periodic, and chaotic solutions. However, in the quest of achieving large amplitude broadband frequency response, assessment of induced strain levels considering the limits on the strain in piezoelectric material has received minimal attention. In this context, the investigation presents analytical formulation for the assessment of induced strain and voltage(s) in piezoelectric unimorph and bimorph cantilevers. The formulation quantifies not only the induced voltages in individual piezoelectric layers of a bimorph, but also the equivalent voltages in parallel and series connection modes, respectively. Also, while computing the induced voltage in the first piezoelectric layer, the contribution from the induced voltage of second piezoelectric layer to the acting bending moment is captured in the formulation. The formulations are validated through the experiments and results from the literature. Further, we have applied two practically useful normalization schemes, the - and -normalizations to the analytical expressions. Using the two normalization schemes, influences of variation of substrate and adhesive layer thicknesses, elastic moduli of layers, and substrate-to-composite length fraction are visualized and discussed. Based on the results, summarized guidelines for design and selection of geometric and material parameters are presented, which may also be applicable for other sensing and actuation applications. At last, practically suitable ranges and optimum values for the normalized design variables are proposed.

Optimising proof mass for cantilever based piezoelectric energy harvester

In this paper the authors propose on optimising the proof mass and device dimensions on the output (voltage, current, power) of a cantilever bimorph based piezoelectric energy harvester using COMSOL multi-physics software. A detailed study of the dimensions of proof mass of the piezoelectric energy harvesters, based on geometry (length, height, and width), material, position and load resistance, had been carried out. The two basic geometries, rectangle, and pyramid were selected to show the influence of proof mass geometry on piezoelectric energy harvester output. The work compared the effect of output with varying proof mass material such as copper (Cu), tungsten (W), palladium (Pd), platinum (Pt), and silver (Ag). Studies show that proof mass placed at the tip with large height (2 mm) in a rectangular shape made of copper gives better output voltage, current, and power of 0.66 V, 55 µA, and 36.4 W respectively.

Acoustical intensity probe based on a polyvinylidene fluoride bimorph.

This study investigates complex acoustical intensity using a polyvinylidene fluoride (PVDF) bimorph. Analytical models of the open-circuit voltage outputs of an infinite-strip-shaped PVDF bimorph cantilever in an underwater sound field are developed. Results show that the sound pressure generates the sum of the outputs, while the particle velocity normal to the PVDF surface generates the difference. The sensitivities of the pressure- and velocity-generated voltage responses with respect to an incident plane sound field demonstrate uniform directivity in a low-frequency range, which is suitable for acoustical intensity determination. The higher velocity sensitivity confirms the advantage of using a PVDF bimorph as a velocity sensor, owing to its light weight and flexibility. An algorithm for determining the complex acoustical intensity normal to the surface is proposed by utilizing those voltage responses and the probe gain calibrated with a given angle of incident sound. This algorithm allows accurate determination of sound intensity of a plane wave field, where the reactive part of intensity is absent. However, a small error may exist when the reactive intensity is large and active intensity is small. This small discrepancy arises from the inherent variation in the phase directivity of the gains, which decrease with frequency.

Experimental Characterization of Optimized Piezoelectric Energy Harvesters for Wearable Sensor Networks.

The development of wearable devices and remote sensor networks progressively relies on their increased power autonomy, which can be further expanded by replacing conventional power sources, characterized by limited lifetimes, with energy harvesting systems. Due to its pervasiveness, kinetic energy is considered as one of the most promising energy forms, especially when combined with the simple and scalable piezoelectric approach. The integration of piezoelectric energy harvesters, generally in the form of bimorph cantilevers, with wearable and remote sensors, highlighted a drawback of such a configuration, i.e., their narrow operating bandwidth. In order to overcome this disadvantage while maximizing power outputs, optimized cantilever geometries, developed using the design of experiments approach, are analysed and combined in this work with frequency up-conversion excitation that allows converting random kinetic ambient motion into a periodical excitation of the harvester. The developed optimised designs, all with the same harvesters’ footprint area of 23 × 15 mm, are thoroughly analysed via coupled harmonic and transient numerical analyses, along with the mostly neglected strength analyses. The models are validated experimentally via innovative experimental setups. The thus-proposed ϕ = 50 mm watch-like prototype allows, by using a rotating flywheel, the collection of low-frequency (ca. 1 to 3 Hz) human kinetic energy, and the periodic excitation of the optimized harvesters that, oscillating at their eigenfrequencies (~325 to ~930 Hz), display specific power outputs improved by up to 5.5 times, when compared to a conventional rectangular form, with maximal power outputs of up to >130 mW and average power outputs of up to >3 mW. These power levels should amply satisfy the requirements of factual wearable medical systems, while providing also an adaptability to accommodate several diverse sensors. All of this creates the preconditions for the development of novel autonomous wearable devices aimed not only at sensor networks for remote patient monitoring and telemedicine, but, potentially, also for IoT and structural health monitoring.

Investigating the performance of tri-stable magneto-piezoelastic absorber in simultaneous energy harvesting and vibration isolation

Tri-stable magneto-piezoelastic oscillators exhibit superior performance in terms of broadband resonance frequency and lower excitation threshold, compared to linear and bi-stable systems. Furthermore, inclusion of magnets renders them applicable, tunable, and simple designs. However, the potential of this oscillators for the purpose of simultaneous vibration suppression and energy harvesting has not been investigated. This study aims to investigate simultaneous energy harvesting and vibration isolation through a tri-stable magneto-piezoelastic absorber (TMPA). The absorber comprises a bimorph cantilever beam carrying a magnetic tip mass and two external magnets. The interplay between magnets generates a nonlinear restoring force in the TMPA structure. This absorber is attached to a host vibrating beam, which is under a transient or periodic forcing, in order to reduce its vibrations and harvest electrical energy. The nonlinear magneto-electromechanical equations governing the coupled system are obtained by employing the Hamilton's principle, Euler-Bernoulli beam theory, and a recently proposed magnetic force relationship. First, the mechanisms of tri-stability formation are investigated via bifurcation diagrams. Next the potency of the TMPA in the transient excitation scenario is examined. Furthermore, the performance of the TMPA in the presence of the periodic excitation with different forcing levels is investigated. Specifically, frequency and time domain analyses are carried out to characterize the response of the system and efficiency of the absorber when TMPA performs periodic in-well, aperiodic inter-well and periodic inter-well oscillations. In addition, to provide a better insight regarding the TMPA performance, the kinetic energies, harvested power, and dissipated power for the region of strongly modulated response are also studied. Moreover, the efficacy of the TMPA in periodic snap-through oscillations is examined by the means of the harmonic balance method in conjunction with pseudo-arclength continuation scheme. Finally, the results disclosed that the proposed tri-stable absorber outperforms a linear absorber in vibration annihilation and energy harvesting.

Analysis of Circular Disc and Bimorph Cantilever Beam Energy Harvesters Under Various Constraint Conditions

Analysis of Circular Disc and Bimorph Cantilever Beam Energy Harvesters Under Various Constraint Conditions

برداشت انرژی با استفاده از تیر بایمورف متخلخل با لایه پیزوالکتریک تحت ارتعاشات القایی ناشی از جریان سیال خارجی

In this study, energy harvesting by porous beams exposed to external fluid flow is studied analytically. The nonlinear electromechanical non-linear differential equations governing the transverse vibration of porous beams under external fluid flow have been extracted using Euler-Bernoulli beam theory and Hamilton's principle. A cantilever bimorph beam with a concentrated mass at its end, which is equipped with piezoelectric layer, is considered as an energy harvesting system. After solving the nonlinear equations of motion, the effect of different parameters on the amount of harvested energy is examined. The results show that in the areas of the lock-in phenomenon, the amount of harvested energy by the beam has its maximum value. Also, the porosity distribution has significant effect on the maximum amplitude of oscillations, as well as the energy harvested by the porous beam. The lock-in phenomenon for the porous beam with distribution of symmetrical porosity (wall stiffness), asymmetric porosity distribution and uniform porosity distribution is taken around u=0.15. In addition, for electrical resistance R = 100kΩ, the maximum voltage generated for the bimorph porous beam by the distribution of symmetrical porosity in the wall stiffness, asymmetric porosity distribution and uniform porosity distribution is 0.39V, 0.44V and 0.57V, respectively.

Optimization of bimorph cantilever based piezoelectric energy harvester for high efficiency

Various attempts are being carried out to convert variety of ambient energies. Every conversion mechanism has its own limitations on efficiency. In this context, piezoelectric phenomenon found to be promising over electromagnetic and electrostatic considering mechanical oscillations in to useful electrical energy. In this work, we use piezoelectric effect because it has an advantage of high converting power efficiency and ease of application. Cantilever uses piezoelectric effect to harvest energy from load. Bimorph cantilever based piezoelectric energy harvester with three different materials; PZT-5A, PZT-8 and cadmium sulfide for three different proof mass patterns 3.5 µm × 2 µm, 3 µm × 2.5 µm, 2.5 µm × 3 µm in the frequency range 60 to –90 Hz and applied load of 100 N to 100 KN has been simulated using software tool COMSOL Multiphysics v 5.2. From the analyses of simulation results, PZT-5A material-based piezoelectric energy harvester with the proof mass dimension of 3.5 µm × 2 µm was found to exhibit maximum efficiency. The reasons for such high efficiency have been discussed in detail by means of physical properties of piezoelectric materials used, range of applied load and proof mass patterns.

Exploiting bi-stable magneto-piezoelastic absorber for simultaneous energy harvesting and vibration mitigation

This paper investigates efficient simultaneous energy harvesting and vibration suppression utilizing a tunable bi-stable magneto-pieozelastic absorber (BMPA). The absorber comprises a bimorph cantilever beam exposed to a magnetic field. Furthermore, it is attached to a primary simply supported beam which is under an external excitation. The nonlinear magneto-electromechanical equations governing the coupled continuous system are derived utilizing the Hamilton's principle. First, the nonlinear magnetic force and its bifurcations are explored. Next, using numerical approaches, the efficacy of the absorber under a transient excitation from energy harnessing and vibration annihilation viewpoints is assessed. Furthermore, the efficiency of the BMPA in a steady-state harmonic excitation is investigated, both in time and frequency domains. Bifurcation diagrams disclosed that, based on magnets gap, the absorber performs periodic in-well low-amplitude oscillations, chaotic inter-well large-amplitude vibrations, or periodic high-amplitude motions. However, it is observed that in inter-well oscillations, chaotic strongly modulated response occurs and efficiency of the BMPA in vibration mitigation and energy harvesting markedly improves, compared to a linear absorber. Moreover, perfection rate examinations disclosed that when vibration suppression and energy harvesting are of the same importance, the bistable PZT absorber performance is 46.5% better than the corresponding linear absorber. Furthermore, when energy harvesting has priority, the BMPA performance is 158% higher than the linear absorber. Finally, harmonic balance method along with pseudo-arclength scheme are exploited to investigate the efficacy in large-amplitude inter-well scenario. It is illustrated that the system solutions are nonlinear and experience various cyclic fold and Hopf bifurcations. Further, the frequency response curves revealed that the BMPA decreases the host structure vibrations. Moreover, in this scenario, a considerable level of voltage is generated over a wide frequency range.

Piezoelectric generator with nonlinear structure

Motion in nature is usually a low-frequency vibration such as walking, running, swinging arms, and so on, but traditional piezoelectric cantilever structures are inefficient at harvesting energy from low-frequency vibrations in the environment. To overcome this, a novel piezoelectric generator was designed. A cantilevered bimorph with a tip mass and a pair of preloading springs were fixed on its base to form a nonlinear piezoelectric generator. The energy transmission in the structure was analyzed. The harvester was modeled as a Euler–Bernoulli beam, and the piezoelectric material was assumed to be linear. The bending vibration was calculated using the Rayleigh–Ritz procedure, and the frequency characteristics of the output voltage were analyzed under different preloading distances. It was found that changing the preloading of the spring helped reduce the natural frequency of the cantilever, which facilitated conversion of ambient low-frequency vibrations into electrical energy. Then, the characteristics of low frequency energy harvesting were investigated experimentally. The theoretical results were consistent with the experimental data; moreover, the resonance frequency, which changes with the preloading distance, reduced from 43 to 35 Hz when the preloading distance was increased from 0 to 1 mm. In this paper, an effective structure to control the resonant frequency is proposed and its motion equation stated. The structure has potential for applications in predicting the effect of preloading distance on resonance frequency.

Fast-moving piezoelectric micro-robotic fish with double caudal fins

Micro-robotic fish (length ≤10 cm) driven by smart materials have remarkable advantages over conventional motors and piston-based robotic fish. In particular, they are highly efficient and compact. One of the key challenges is attaining high mobility with high energy density, low driving voltage and power loss. In this work, a double caudal fin micro-robotic fish actuated by two piezoelectric bimorph cantilevers is proposed and fabricated from rigid carbon fiber/resin composites and flexible polyimide hinges. Its weight is about 1.93 g and the maximum uniform swimming velocity is as high as about 0.75 BL/s (4.5 cm/s), which is much faster than previously reported micro-robotic fish actuated by ionic polymer–metal composites, shape memory alloys and dielectric elastomers. A theoretical model is validated by the experimental results and can be used to design and analyze a variety of piezoelectric robotic fish propelled by caudal fins.

Measurement of quasi-static and dynamic mechanical properties of soft materials based on instrumented indentation using a piezoelectric cantilever

Instrumented indentation is a powerful in-situ mechanical characterization method and has been intensively investigated in recent years. In this work, we proposed an instrumented indentation method for soft materials based on a piezoelectric bimorph cantilever where the indentation force (F) is measured by a strain gauge and the indentation depth (h) is monitored by a piezoelectric motor driven displacement platform. The quasi-static mechanical properties of the soft samples are obtained by using the F-h curve and the dynamic properties are extracted from the contact resonance curve of the piezoelectric cantilever which is measured by using electromechanical impedance (EMI). Firstly, the working principle of this indentation method for quasi-static and dynamic mechanical property measurement is presented. Then, both the quasi-static and dynamic indentation testing were conducted on a silica gel sample, and the testing results fit well with that obtained using tensile testing. Later, the viscoelastic properties of a Polydimethylsiloxane (PDMS) sample was tested which is strongly dependent on the indentation force. Finally, modulus imaging was conducted on a silica gel sample containing a stiffer elastomer sphere using the local contact stiffness (LCS) as the indicator, and the elastomer can be clearly revealed. The proposed piezoelectric cantilever based instrumented indentation method is very convenient for mechanical characterization of soft materials and may be widely used in near future.

Performance analysis of bimorph cantilever beam using piezoelectric materials and MEMS technology

This research paper is an attempt to present an insight into the use of micro electromechanical systems (MEMS) technology harvesting of green energy. One of the common examples of MEMS technology is by utilizing bimorph cantilever beams. Subsequently, it has also been discussed that Bimorph cantilever beam based sensors with high sensing ability could be used for harvesting energy from the physical environment. In this paper, we concentrate on the comparative analysis of the MEMS and piezoelectric materials which are used to design bimorph cantilever beams and convert mechanical energy into electrical energy. Detailed performance analysis of bimorph cantilever beams made of different materials has been carried out through various simulation models. Design and the simulation of bimorph cantilever beam is performed using Comsol multiphysics 5.2. state of art software. Comparative analysis of Lead zirconate (PZT-4D) and Lead zirconate (PZT-7A) has been done in this research to find more suitable material for fabrication of bimorph cantilever beams. PZT-7A is found to provide better electrical output for various analysis performed.

Graded multifunctional piezoelectric metastructures for wideband vibration attenuation and energy harvesting

Unlike well-studied locally resonant (LR) metamaterials with a periodic array of identical resonators, ‘graded’ LR metamaterials consist of an array of resonators with a spatially varying parameter, yielding wideband wave attenuation and mode trapping/localization, among other features. In this work, we explore a graded LR piezoelectric metamaterial-based structure (i.e. metastructure) in which the grading parameter, namely the inductive shunt resonant frequency of the unit cells, follows a predefined variation pattern in space (e.g. first-order, quadratic, or fractional). We investigate the effect of such patterns on (i) the vibration attenuation bandwidth, (ii) the localization of vibration modes, and (iii) the harvested power. To this end, we consider a piezoelectric bimorph cantilever hosting an array of piezoelectric unit cells with spatially varying inductive shunts. Fully coupled electromechanical equations describing the metastructure’s linear transverse displacement and unit cell voltages are given with a modal analysis framework and solved using the matrix inversion method. The results show that (i) the first-order grading pattern yields the widest bandgap with 65% increase in the bandwidth compared to the standard uniform LR pattern, (ii) the localization of vibration modes follows in shape the corresponding frequency grading pattern, and (iii) the largest power is harvested for the fractional grading pattern. Furthermore, all of the graded resonator configurations result in wider bandwidth in energy harvesting as compared to the uniform resonators case. Overall, the results unveil the fundamental characteristics of this class of graded piezoelectric metastructures and support the design of such multifunctional piezoelectric metastructures for concurrent vibration attenuation and energy harvesting.

Design of Vibration-Sourced Piezoelectric Harvester for Battery-Powered Smart Road Sensor Systems

Energy harvesting is crucial for battery-powered smart sensing systems to remain functional for a longer period of time without any intervention. Utilizing road vibrations, as the source to harvest energy, for smart road sensing systems is of a significant interest. Many studies on implementing distinctive designs for vibration-sourced harvesters are currently in progress. In this paper, a vibration-sourced piezoelectric energy harvester, which has been validated by the simulation results from COMSOL Multiphysics, is proposed. The design comprises two Lead Zirconate Titanate (piezoelectric ceramic material) PZT-5J mass-spring oriented cantilever bimorphs to capture the vibrations and three silicone rubbers to increase the stress applied on the bimorphs. This productive piezoelectric energy harvester has been designed to be used in low- and high-vibration conditions. A maximum power output of 57 mW has been obtained by the designed energy harvester. The simulation results prove that the proposed piezoelectric energy harvester design is efficient to supply power to sensors and wireless systems used in smart road applications. Based on the obtained simulation results, a prototype has been developed. Considering the real environmental aspects, the prototype has been modified to accommodate the requirement of sustaining and long-lasting design.

Semi-analytical model of an acoustic black hole piezoelectric bimorph cantilever for energy harvesting

An acoustic black hole (ABH) beam termination can be achieved by decreasing its thickness according to a power-law profile. Waves entering the ABH slow down and vibrational energy strongly concentrates at the tip of the beam. This can be exploited for energy harvesting, as suggested in some recent works. The finite element method (FEM) is commonly used to carry out the simulations, which hampers long parametric analyzes. In this paper, we develop a semi-analytical approach to characterize the performance of a piezolectric bimorph cantilever with an ABH termination. The method can be easily extended to further configurations and allows one to determine ABH harvesting capabilities when varying system parameters, in a fast and efficient way. The Lagrangian of the ABH beam plus piezoelectric layers is constructed and the coupled equations for the flexural vibrations and voltage are derived from it. The flexural displacement field is expanded in terms of Gaussian basis functions. Vibration shapes and harvested power are computed with the proposed method and validated against FEM simulations. The ABH piezolectric bimorph cantilever is shown to substantially enhance the harvesting capabilities of a cantilever with uniform cross-section. The semi-analytical approach is then used to examine the influence of several ABH and piezoelectric layer parameters on energy harvesting efficiency. As regards the former, the effects of the tip truncation thickness and ABH order are explored. In what concerns the piezoelectric layer, we investigate the effects of its location, thickness, splitting it into several patches and varying the load resistors to enhance its performance in a broad frequency range. The proposed method constitutes a valuable tool for the design of ABH energy harvesting devices.