Vibration Power Research Articles

Application of Various Materials With Negative Saturation Magnetostriction to Vibration Power Generation

Various materials with negative saturation magnetostriction were applied to a U-shaped unimorph device for vibration power generation using inverse magnetostrictive effect. When an fcc Fe-Ni alloy with the positive saturation magnetostriction was attached as an inverse magnetostrictive material on the front side of a U-shaped frame, larger values of the open-circuit voltage <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">op</sub> were obtained in comparison with that of the frame core device without a sample. However, when an fcc Ni metal with the negative saturation magnetostriction was attached on the front side of the U-shaped frame, its <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">op</sub> value was almost same as that of the frame core device. Larger <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">op</sub> values were obtained by attaching the fcc Ni metal on the back side of the U-shaped frame. Similar characteristics were observed in the devices using a bcc Fe metal and an hcp Co metal with negative saturation magnetostriction. Therefore, the back side setting is effective for the application of materials with negative saturation magnetostriction to the U-shaped unimorph device.

Underwater Target Detection by Measuring Water-Surface Vibration With Millimeter-Wave Radar

Underwater target detection has been a significant challenge in environment aware. In this letter, an underwater target detection scheme is proposed by measuring the water-surface vibrations caused by acoustic waves with a millimeter-wave radar. Firstly, the power of the water-surface vibration due to the reflection of acoustic waves by the target is derived, which gives a quantitative relationship between the perturbations on water-surface vibration and the position of the target. Then, the signal model to accurately measure the water-surface vibration with millimeter-wave radar is established. A method to estimate the power spectrum of the phase of water-surface vibrations is proposed, based on which a test statistic for underwater target detection is formulated. Finally, the effectiveness of the proposed scheme is validated by water-tank experiments using a frequency modulated radar with a center frequency of 77 GHz.

An experimental study on a wind-induced vibration power generator for orientation-adaptive energy harvesting

Batteries with a limited lifespan have gradually failed to meet the development needs of some low-power electronic products. Harvesting wind energy to power the above devices has been a promising way. Facing the time-varying characteristics of wind direction and velocity in the natural environment, an efficient orientation-adaptive energy harvester (OAEH) based on the piezoelectric effect is proposed. An experimental test system is established to probe into the output and adaptive performances of the OAEH. The experimental results indicate that improving the inertia of the tray can abate the initial wind velocity and enhance the output power to a certain extent. The relative deviation (γ) of power integration areas at different inclinations is less than 3%. The harvester has 364.86% enhancement in average power integration area comparing that with the fixed shaft. Besides, the OAEH can drive a monitoring device with a display screen and integrated sensors, which can be utilized to monitor the condition of the bridge, flyover, and so on.

Probing the local structures of Choline-Glycine Electrolytes: Insights from ab initio simulations

Amino acid ionic liquids have garnered significant attention for their potential in electrochemical energy storage due to their wide electrochemical stability windows and inherent safety. The performance of ChGly as an electrolyte for supercapacitors has been compared to that of highly efficient conventional ionic liquids. However, a thorough understanding of the microstructural characteristics responsible for the enhanced properties of ChGly aqueous solutions remains largely unexplored. In this study, ab initio molecular dynamics simulations were employed to investigate the energetic, structural, transport and spectroscopic properties of ChGly-based pure and aqueous electrolytes. A comprehensive analysis of the cation–anion and water-ion hydrogen bonding was conducted for both electrolyte systems. Structural features were examined using radial and spatial distribution functions, while the vibrational power spectra were analyzed to identify significant differences in intermolecular interactions between pure and aqueous electrolytes, stemming from modified solvation shell structures. The findings presented in this work shed light on crucial structural and spectroscopic distinctions between pure and aqueous ChGly electrolytes, providing valuable insights for further advancements in the field.

Harvesting and mapping ultrasonic vibration power using semiconducting wire-based tribovoltaic generators

Ultrasonic vibration is an excellent mechanical power source owing to its large power density. Harvesting ultrasonic vibrations has been demonstrated so far through piezoelectric effect, triboelectric effect, and electromagnetic induction. However, the majority of these devices only produce AC output which limits their potential applications. This work demonstrates, for the first time, the conversion of ultrasonic vibration power to DC output using semiconducting wire-based electric generators, in which one or several semiconductor wire/metal junction(s) are employed. A current density of up to 19 µA/cm2 and a peak power density of 5 µW/cm2 can be obtained under ultrasonic vibrations up to 37 kHz. The mapping of the ultrasonic vibrational strength has been achieved, demonstrating the capability of a self-driven powered ultrasonic sensor. The characteristics of individual semiconductor junctions and the series connection of several such junctions are studied using equivalent circuits.

Detecting gas pipeline leaks in sandy soil with fiber-optic distributed acoustic sensing

Detecting pinhole leaks in long-haul buried gas pipelines is challenging due to weak leak signals and large spans. Fiber-optic distributed acoustic sensing (DAS) technology offers highly sensitive long-distance monitoring. This study evaluates DAS for detecting pinhole gas leaks in pipelines buried in sandy soil. Controlled experiments examined the effects of pipe-to-fiber distance, fiber position, leak direction, gas pressure, and leak diameter. Pressurized gas erodes the overlying soil, forming cavities and fissures that change soil morphology. Gas preferentially diffuses upward; an optical fiber above the pipe has the highest sensitivity regardless of leak direction and should be deployed above pipelines. Two mechanisms produce DAS-recorded leak vibration signals: dynamic soil straining and gas–fiber friction. Vibration energy from dynamic soil motion concentrates at 60–120 Hz while gas–fiber friction exhibits a broader spectral response. Increasing gas pressure or leak diameter increases detected vibration power but decreases peak frequency and proportion generated by soil strain, indicating a shift toward gas–fiber friction as the dominant mechanism. These results inform improved pinhole leak monitoring in buried gas pipelines using DAS technology.

Optimal Sizing of Trailing Edge Flaps for Helicopter Vibration Reduction: A Response Surface Approach

On-blade active trailing edge flaps are considered for helicopter vibration reduction. A Pareto optimal multi-objective optimization approach is used to obtain the spanwise and chordwise dimensions of single and dual trailing- edge flaps. The objective of this study is to simultaneously achieve minimum hub vibration levels and minimize the flap actuation power requirement. Helicopter aeroelastic analysis is used in conjunction with an optimal controller to minimize hub vibration and flap power levels. It is found that nonlinear polynomial response surfaces based on L9 orthogonal array could adequately describe both the objectives. An intense sampling of the surrogate objective space is used to obtain optimal design points for the mutually conflicting objectives. A Pareto optimal design reduces vibration levels by about 70% and also reduces flap actuation power requirement by about 20%, in comparison to the initial design. The present study leads to an optimal design of trailing edge flaps which expend less power and can be further explored for self-powered control surfaces towards a self-powered smart blade design concept. The optimal designs are robust to uncertainty introduced by manufacturing.

Vibration energy transfer in variable stiffness laminated composite panel with a cutout

This study investigates the vibration power flow transmission behavior of laminated composite plates with a cutout and a variable angle tow (VAT) design. The steady-state response of the harmonically excited plate is determined. The power flow density vectors (PLDV) are used to show the vibration transmission paths. The effects of the VAT design parameters on the dominant power flow paths within the plate are explored. It shows that the forced vibration responses and vibration energy transfer within the structure can be tailored with fiber layer scheme. The findings benefit enhanced vibration suppression of composite plates with a cutout.

Establishment of a flow-induced vibration power database based on deep neural network machine learning method

In this paper, a machine learning method based on Deep Neural Network (DNN) is used to establish a predictive model for flow-induced vibration (FIV) power output, and the power database is constructed based on this model. The results reveal that the power database can quickly and efficiently obtain power values for any parameter combination, significantly improving the efficiency of studying the power response of flow-induced vibration. Its accurate prediction ability, low cost and time consumption have made the database a useful tool. Furthermore, the power database can provide power values for various parameter combinations to comprehensively analyze the impact of system parameter combinations on power. The screening results indicate that the optimal power output for the single oscillator flow-induced vibration energy harvesting is 22.71W and the optimal power for the dual oscillator FIV energy harvesting is 36.38W. A power database of single and dual oscillators flow-induced vibration harness energy provides a novel method for the study of flow-induced vibration power generation.

Evaluation of aircraft random vibration under roughness excitation during taxiing

The assessment of runway smoothness or roughness is intimately tied to the vibrational response of aircraft during taxiing. In this study, employing the pseudo excitation method (PEM) based on random vibration analysis, we unearthed the relationship between the random vibrations of five distinct aircraft types and runway irregularities. Initially, we established two three-dimensional (3D) models of aircraft taxiing vibration and derived the response output under roughness excitation. Subsequently, we employed MATLAB to analyze the power spectral characteristics of the vibrational response in different parts of the aircraft. Lastly, we examined the effects of taxiing speed, aircraft type, runway roughness, and lift on the aircraft's vibration. Our findings indicate that the distribution of vibration power spectral density (PSD) exhibits multiple peaks, correlating with the degrees of freedom of the aircraft. We further note that the frequency that aligns most closely with the response peak should be the focus of investigation. High-frequency excitation impacts the pilot and nose landing gear more significantly than the passenger and main landing gear. Absent the consideration of lift, increased taxiing speed amplifies the impact of roughness excitation on aircraft taxiing safety. Larger aircrafts are more sensitive to long-wave roughness. With lift in consideration, all aircraft types exhibit a speed sensitivity to vibration, which should be the primary concern in runway roughness evaluations.

High-efficiency regenerative shock absorbers considering twin ball screws transmission for increasing the vehicles’ driving range using a hybrid approach

This article proposes a hybrid system for increasing the electric vehicles’ (EVs) driving range considering regenerative shock absorbers. The proposed hybrid approach is a combination of atomic orbital search (AOS) and wild horse optimizer (WHO); later, it was called AOSWHO method. The major objectives of the proposed work are to extend vehicle range, reduce the charging time of the vehicle, reduce the battery size, and increase the efficiency of vehicle. In this proposed work, linear Permanent magnet (PM) generators are used as the sole instrument and on-board source is utilized to absorb vibration energy of the moving vehicle. Here, the proposed method has four key modules: (a) suspension vibration input, (b) transmission mechanism, (c) generator module, and (d) power storage. A suspension vibration is mostly pretentious by road roughness and speed vibration, which is optimally handled by the proposed hybrid technique. The conversion of the alternating linear vibration into unidirectional rotation of generator shaft is processed by proposed hybrid technique. Based on the volume and efficiency of the dampers, a small volume, brushless DC motor with low rotor inertia is selected to produce electricity. By then, the proposed AOSWHO run on MATLAB site and its performance is related to several existing systems. From the simulation result, it is concluded that proposed system delivers an State of Charge (SOC) of 40.33, which is high compared to existing approaches.

Research on Dual-Functional Properties of an Asymmetric Piezoelectric Metamaterial Beam for Simultaneous Vibration Reduction and Power Generation

Research on Dual-Functional Properties of an Asymmetric Piezoelectric Metamaterial Beam for Simultaneous Vibration Reduction and Power Generation

Enhancing performance in organic solid structures and heat transfer with single annealing process and variable rates

Molecular dynamics has been widely adopted in a variety of fields, especially for organics. Annealing is an extensively used model-optimization method that can be found in many studies. However, how to achieve the best-annealed model within limited calculation time has not been studied. Therefore, using n-octadecane as an example, we investigated the effect of annealing on the structure and properties within the same calculation time. Two different types of annealing were performed. One was multiple cycles with uniform annealing rates, the other was a single cycle with variable annealing rates. The degree of order in the molecule and the system was characterized by the radius of gyration and X-Ray diffraction, and the mechanism was explained through density variation. The effect of annealing on the properties was investigated by simulating thermal conductivity and the reasons were analyzed using vibration power spectra. The results showed that at the same calculation time, a single annealing cycle with a reduced annealing rate of the solid phase can achieve a better structure. If the annealing rate is higher than the initial cooling rate, the system structure will be damaged. The well-annealed system exhibited serious overheating and slight supercooling, and had a high thermal conductivity. Annealing can affect the intensity of the characteristic peak, but it does not change its frequency. The value of thermal conductivity is positively correlated with the total intensity of characteristic peaks. Our study aims to guide future simulations involving annealing processes to significantly improve the accuracy of solid-state models and prevent structural damage caused by improper annealing operations.

Unraveling local structures of Salt-in-Water and Water-in-Salt electrolytes via ab initio molecular dynamics

Water-in-salt electrolytes (WiSE) are attractive for electrochemical energy storage applications owing to their wide electrochemical stability windows and inherent safety. The high concentration of salts is widely known to suppress the decomposition of water, which otherwise limits the stability of conventional aqueous salt-in-water electrolytes (SiWE). Nevertheless, the microstructural features of WiSE that lead to this enhanced stability have not yet been fully elucidated. In this work, ab initio molecular dynamics simulations were performed to study the energetic, structural, and spectroscopic properties of LiTFSI SiWE and WiSE solutions. A detailed mapping of water-water and water-anion hydrogen bonding and cation–anion electrostatic interactions is reported for both electrolytes. Structural features are presented in terms of both radial and spatial distribution functions. Analysis of IR and vibrational power spectra reveal key differences in the intermolecular interactions in SiWE and WiSE that arise from modified solvation shell structures. The results obtained herein reveal the most important structural and spectroscopic differences between the electrolytes in normal and superconcentrated concentrations.

Power exchanged between subsystems with non-diffuse fields in statistical energy analysis.

This article is a discussion on the necessity of the assumption of diffuse field in statistical energy analysis and the validity of the coupling power proportionality which states that the vibrational power exchanged between coupled subsystems is proportional to the difference of their modal energies. It is proposed to re-formulate the coupling power proportionality in terms of local energy density instead of modal energy. We show that this generalized form remains valid even if the vibrational field is not diffuse. Three causes of lack of diffuseness have been studied: coherence of rays in symmetrical geometries, nonergodic geometries, and the effect of high damping. Numerical simulations and experimental results conducted on flat plates in flexural vibration are provided to support these statements.

Experimental study of wind energy harvesting from flow-induced vibration of prisms using magnetostrictive material

A vibration energy harvester was developed using a magnetostrictive material as a power generator and a prism as a wind receiver to harvest energy from low-speed wind by exploiting flow-induced vibration. The present cantilevered vibration power generator has originality for the structure which consists of a U-shaped unimorph beam of Galfenol (iron-gallium alloy). Wind tunnel experiments were conducted for prisms having circular, rectangular, filleted triangular, and V-shaped cross-sections. We focused on transverse vortex-induced vibration for a circular cylinder and low-speed galloping vibration for a rectangular prism with a depth-to-height ratio of 0.2, a filleted triangular prism, and a V-shaped prism. The effect of the width of prisms having a span length of L = 200 mm on the transverse vibration characteristics and the power extracted from the vibration generator was investigated. The maximum power generated by cylindrical, rectangular, filleted triangular, and V-shaped prisms with heights of 50, 50, 60, and 50 mm was 1.28, 3.5, 7.83, and 5.02 mW, respectively. These maximum power levels are enough to run a wireless sensor. Moreover, the angle of the V-shaped prism having a width of 50 mm was varied (i.e., β=60°, 90°, 120°, and 150°) and tested in wind tunnel experiments. The V-shaped prism with β=120° was best from several viewpoints, including low excitation wind speed, safe operation at high wind speed, efficient operation in environmental conditions, and sustainability.

Vibrational Power Flow Analysis for the Sandwich Cylindrical Shell Structure with a Metal–Rubber Core in the Thermal Environment

This research is designed to investigate the vibrational characteristics of a sandwich cylindrical shell structure with an elastic-porous metal–rubber core in the thermal environment by the power flow method. The finite element models of the homogeneous and sandwich cylindrical shell structures are established for harmonic response analysis completed by the mode superposition method. Further, the structural power flow is calculated and visualized based on the results of the finite element analysis. A comparison is made with the results for a plate available in the literature validating the effectiveness of the power flow visualization method. The effects of some key factors, such as the frequency, the metal–rubber core, the length-to-radius ratio, and the temperature on the power flow of the sandwich cylindrical shell structure, are analyzed using power flow cloud pictures and vector diagrams. The results reveal that the frequency affects the distribution of power flow, and the metal–rubber core can dissipate energy, whereas the length-to-radius ratio and temperature do not have a significant influence on the power flow of the sandwich cylindrical shell structure with a metal–rubber core (SCSMR). This work should be valuable for the noise and vibration control application of the SCS-MR.

Ultrasonic Vibration-Assisted Stamping of Serpentine Micro-Channel for Titanium Bipolar Plates Used in Proton-Exchange Membrane Fuel Cell.

Metallic bipolar plates (BPPs) are key components in the proton-exchange membrane fuel cell (PEMFC), which can replace traditional fossil fuels as a kind of clean energy. However, these kinds of plates, characterized by micro-channels with a high ratio between depth and width, are difficult to fabricate with an ultra-thin metallic sheet. Then, ultrasonic-vibration-assisted stamping is performed considering the acoustic softening effect. Additionally, the influence of various vibration parameters on the forming quality is analyzed. The experimental results show that ultrasonic vibration can obviously increase the channel depth. Among the vibration parameters, the vibration power has the maximum influence on the depth, the vibration interval time is the second, and the vibration duration time is the last. In addition, the rolling direction will affect the channel depth. When the micro-channels are parallel to the rolling direction, the depth of a micro-channel is the largest. This means that the developed ultrasonic-vibration-assisted stamping process is helpful for improving the forming limitation of micro-channels used for the bipolar plates in PEMFC.

Air-side heat transfer enhancement in fin-tube heat exchangers using forced vibrations under various conditions

Forced vibrations can occur in fin-tube heat exchangers (FTHEs) by compressors, fans, and the driving conditions of automobiles. Accordingly, the effects of forced vibrations on the heat transfer performance of FTHEs in refrigeration systems and heat pumps should be investigated in detail for their practical design. However, few studies have investigated the improvement in heat transfer by vibrations in FTHEs. In this study, air-side heat transfer enhancement in FTHEs by applying forced vibrations is experimentally investigated. The heat transfer performance of the FTHEs was measured by varying the air-side Reynolds number, vibrational frequency, vibrational amplitude, and fin pitch. For practical purposes, the heat transfer characteristics of the FTHEs were analyzed under constant vibrational power, force, and velocity. The heat transfer enhancement increased with an increase in the vibrational frequency, amplitude, and fin pitch, whereas it decreased with an increase in the air-side Reynolds number. A correlation for heat transfer enhancement using forced vibrations was developed as a function of nondimensional operating and geometrical parameters. The results can be used to predict heat transfer enhancement by vibrations and the FTHE design for heating, ventilating, and air-conditioning systems.

Layering Vibration Transfer Path Analysis of a Flexible Supported Gear System Based on the Vibration Power Flow Theory

In the marine gear system, the vibration of gears is transmitted to the ship foundation through shafts, bearings, housing, and isolators, and then the underwater noise is generated. Analyzing the vibration transfer properties and identifying the critical path can provide guidance to the low-noise design of the gear system. In this paper, a coupled gear-housing-foundation dynamic model is proposed for a flexible supported gear system, in which the flexibility of each subsystem and the coupling relationship between them are taken into account. The transferring process of gear vibration is divided into different layers between gears, shafts, bearings, housing, isolators, and ship foundation. Based on the vibration power flow (VPF) theory, detailed layering vibration transfer path analyses of the gear isolation coupled system are carried out for both location path and direction path, and the main paths are identified in a broad speed range. The results indicate that though the gear vibration transferred to the foundation attenuate layer by layer, there may be reverse VPF in some special location path and direction path under resonance conditions.