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Active vibration control of gearbox housing using inertial mass actuators

smart materials AND structures 2024年第9期33卷 095008-095008页

作者： Okda, Sherif Nampally, Sneha Rupa Fontana, Mauro Herold, Sven Nordmann, Rainer Rinderknecht, Stephan Melz, Tobias Tech Univ Darmstadt Mech Engn Dept Res Grp Syst Reliabil Adapt Struct & Machine Acous Otto Berndt Str 2 D-64287 Darmstadt Germany Tech Univ Darmstadt Mech Engn Dept Res Grp Mechatron Syst Mech Engn Otto Berndt Str 2 D-64287 Darmstadt Germany Powerflex SRL Via Campitiello 6 I-82030 Limatola Italy Fraunhofer Inst Struct Durabil & Syst Reliabil LBF Bartningstr 47 D-64289 Darmstadt Germany

Reducing carbon emissions is a primary goal in the global effort to combat climate change. Decreasing the weight of a vehicle improves efficiency and significantly reduces emissions. One of the main contributors to the vehicle's weight is the gearbox. However, this approach presents a challenge as lightweight transmission systems experience higher vibrations and noise emission levels. In this paper, an economical active vibration control system is developed to control the vibration levels of an automotive gearbox housing. The gearbox's mounting points are targeted to reduce the transmitted vibrations to the car cabin. The active control system aims to target high-frequency vibrations between 1000 Hz and 5000 Hz. A compact piezoelectric inertial mass actuator is designed and tested on a gearbox-constructed setup that simulates the vibrations and noise similar to a commercial automotive transmission system. The developed test-rig is excited by a piezo stack actuator at the input shaft. Filtered-x least mean square algorithm is implemented on a high-speed microcontroller, and the vibration levels are significantly reduced using the active system. An average reduction of approximately 8.5 dB is achieved between 1000 Hz and 1500 Hz, an average reduction of approximately 14 dB is obtained between 1500 and 2000 Hz, and an average reduction of 10.8 dB is attained between 2500 and 5000 Hz.

关键词： active vibration control smart structures piezoelectric inertial mass actuator gearbox housing

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Transparent heat reflecting PVA/Cu/PVA photonic structures for energy saving smart windows

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materials CHEMISTRY AND PHYSICS 2025年 336卷

作者： Jinsi, C. P. Hamna, N. Meenu, M. S. Avarachan, Anu Varghese, Akhil Issac, Riju C. Cochin Univ Sci & Technol CUSAT Dept Phys Intense LAser Matter Interact ILAI Grp Kochi 682022 Kerala India

Development of transparent heat reflecting, hence energy-saving windows using cost-effective materials has a pivotal role in interior temperature control of buildings, especially considering the regular growth in ambient temperature globally. The present article focuses on developing polymer/metal/polymer transparent heat reflection (THR) multilayer coatings on glass substrates. We have used polyvinyl alcohol as the polymer and copper films as metal coatings in the three-layer stack that was fabricated. We investigate the structure, uniformity, continuity, and optical properties of PVA/Cu/PVA multilayers using Field Emission Scanning Electron Microscope, ellipsometry, stylus profilometer, and UV-VIS-NIR spectrophotometer. The optical modeling using COMSOL Multiphysics software optimizes individual layer thickness. Annealing at 70 degrees C enhances the THR property and improves crystallinity. Samples annealed at 70 degrees C for 30 min with 95 nm thick PVA (2w/v %) and Cu of 15 nm thickness show maximum optical transmittance of 76.6 % in the visible band centered at 605 nm while transmitting only approximate to 9.2 % at 2000 nm in the infrared region. The high visible transmittance and low infrared transmittance of the PVA/Cu/ PVA multilayer have the potential for energy-saving smart window applications.

关键词： Heat reflecting window Transparent heat reflector Energy saving glass smart window Multi-functional glazing Photonic crystal

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Multi-direction vibration isolation via transverse isotropy control of metal rubber

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smart materials AND structures 2025年第1期34卷 015040-015040页

作者： Ma, Yanhong Tang, Xiangxin Wang, Yongfeng Hong, Jie Beihang Univ Res Inst Aeroengine Beijing 100191 Peoples R China Beihang Univ Sch Energy & Power Engn Beijing 100191 Peoples R China

Metal rubber (MR) is widely used for vibration isolation due to its high damping and designable stiffness, but the isolation efficiency is relatively low in the non-molding direction due to its transverse isotropy. In this paper, the transverse isotropy of MR is controlled by design of manufacturing parameters (wire diameter, spiral diameter and compression ratio), material parameter (relative density) and geometric structure, to improve the isolation efficiency in the non-molding direction. Firstly, the helix unit was adopted to establish the relation between the transverse isotropy of MR material and manufacturing parameters, and manufacturing parameters were designed to control the transverse isotropy of MR material. Next, based on parametric modeling and genetic algorithm, material parameters and geometric structure were optimized to control the transverse isotropy of MR isolator. Finally, the transverse isotropy of the designed MR isolator was tested by quasi-static experiments, and multi-direction vibration isolation performance was verified by random vibration experiments. It is demonstrated that the transverse isotropy is controlled efficiently, and the vibration isolation efficiencies of the proposed MR isolator are all up to 85% under 15-2000 Hz broadband random vibration in X, Y and Z directions.

关键词： metal rubber transverse isotropy vibration isolation random vibration

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Ultrastrong Coupling between Polar Distortion and Optical Properties in Ferroelectric MoBr2O2 (vol 146, pg 15411, 2024)

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JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 2024年第32期146卷 22860-22860页

作者： Li, Zhaojun Varrassi, Lorenzo Yang, Yali Franchini, Cesare Bellaiche, Laurent He, Jiangang School of Mathematics and Physics University of Science and Technology Beijing Beijing 100083 China Department of Physics and Astronomy “Augusto Righi” Alma Mater Studiorum Università di Bologna Bologna 40127 Italy Faculty of Physics and Center for Computational Materials Science University of Vienna Kolingasse 14-16 Vienna 1090 Austria Smart Ferroic Materials Center Physics Department and Institute for Nanoscience and Engineering University of Arkansas Fayetteville Arkansas 72701 United States Key Laboratory of Advanced Materials and Devices for Post-Moore Chips Ministry of Education University of Science and Technology Beijing Beijing 100083 China

Tuning the properties of materials by using external stimuli is crucial for developing versatile smart materials. Strong coupling among the order parameters within a single-phase material constitutes a potent foundation for achieving precise property control. However, cross-coupling is fairly weak in most single materials. Leveraging first-principles calculations, we demonstrate a layered mixed anion compound MoBr2O2 that exhibits electric-field switchable spontaneous polarization and ultrastrong coupling between polar distortion and electronic structures as well as optical properties. It offers feasible avenues of achieving tunable Rashba spin-splitting, electrochromism, thermochromism, photochromism, and nonlinear optics by applying an external electric field to a single domain sample and heating, as well as intense light illumination. Additionally, it exhibits an exceptionally large photostrictive effect. These findings not only showcase the feasibility of achieving multiple order parameter coupling within a single material but also pave the way for comprehensive applications based on property control, such as energy harvesting, information processing, and ultrafast control.

关键词： Chemical structure Light materials Phase transitions Polarization

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High-throughput screening of novel silicon allotropes in Fmmm phase with unique electronic physical performances and potential photovoltaic applications

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COMPUTATIONAL materials SCIENCE 2025年 248卷

作者： Jia, Min Fan, Qingyang Gao, Dangli Pang, Qing Yun, Sining Xian Univ Architecture & Technol Coll Sci Xian 710055 Peoples R China Shaanxi Key Lab Nano Mat & Technol Xian 710055 Peoples R China Xian Univ Architecture & Technol Coll Informat & Control Engn Xian 710055 Peoples R China Xian Univ Architecture & Technol Sch Mat Sci & Engn Funct Mat Lab FML Xian 710055 Peoples R China

Pioneer of semiconductor materials, named monocrystalline silicon, holds important applications in solar cells and microelectronics based on their unique semiconductor properties. Here, by a random strategy combined with group and graph theory and high-throughput calculations, 19 new Fmmm phase silicon allotropes have been proposed, including 6 quasi direct or direct band gap semiconductors, 1 metal characteristic allotrope, and 12 indirect band gap semiconductors. The mechanical stability, thermal stability, and dynamic stability of these 19 novel silicon allotropes are thoroughly studied by the elastic constants, relative enthalpies, molecular dynamics, and phonon spectra. As expected, these structures not only meet all stability criterions, but also exhibit excellent physical properties. Especially, these silicon allotropes exhibit three times higher visible light absorption capacity relative to diamond Si, indicating great potential for application in the field of solar photovoltaics. Considering the possibility of laboratory synthesis, we conducted X-ray diffraction for providing more insights into their structure. The design of new silicon allotropes reported in this study may encourage the design and development of smart silicon materials for future more sophisticated application of photoelectricity technology.

关键词： High-throughput calculations Crystal-structure prediction Electronic property Density functional theory Photovoltaic applications

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An Overview of Adaptive structures Engineering Activities at CIRA

An Overview of Adaptive Structures Engineering Activities at...

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AIAA Science and Technology Forum and Exposition (AIAA SciTech Forum)

作者： Concilio, A. Ameduri, S. Dimino, I Brindisi, A. Ciminello, M. Galasso, B. Ctr Italiano Ric Aerosp Capua Italy

ISBN: (纸本)9781624106316

On July 1(st), 2000, the Lab of smart structures was established at CIRA, among the first of that kind worldwide. The aim was to set an early foot within the recently newborn discipline, which was growing more and more in terms of attention and participation within the aerospace community. Moving from basic experiences on piezoelectric ceramics technology and fiber optics, soon the activities moved to include shape memory alloys, and set finally the focus on active noise and vibration control via smart materials, morphing, and integrated sensing. Almost ironically, along the development pathway it became evident that a smart structure should have not necessarily based on the use of smart materials, but the technology attainments made it possible to include COTS actuation systems. To avoid misunderstandings, the Lab name was then changed into Adaptive structures, which currently represents one of the research branches within CIRA. This article tries to figure out the current status of the research on the topic, giving an eye to its background.

关键词： Piezoelectric ceramics

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Vibration control of cantilever beam using poling tuned piezoelectric actuator

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MECHANICS BASED DESIGN OF structures AND MACHINES 2023年第4期51卷 2217-2240页

作者： Singh, Kamalpreet Sharma, Saurav Kumar, Rajeev Talha, Mohammad Indian Inst Technol Sch Engn Mandi 175005 Himachal Prades India

This paper presents active vibration control of smart cantilever beam using poling tuned piezoelectric actuator. The vibrating response of piezo-laminated cantilever beam is modeled using a lumped parameter approach. The fuzzy logic controller is used to control the vibration and 49 rules have been established to develop the controller. Sensor voltage and derivative of sensor voltage are considered as inputs while the actuator voltage is considered as an output. Different piezoelectric materials are considered for analysis to improve the performance of the piezoelectric actuator layer using poling tuning phenomena which further enhances the control performance. In Poling tuning phenomena, poling is done at an angle due to which different piezoelectric strain coefficients i.e., transverse (d(31) mode), longitudinal (d(33) mode), and shear (d(15) mode) are activated simultaneously and start contributing toward effective piezoelectric strain coefficient. The poling angle corresponding to the maximum magnitude of effective piezoelectric strain coefficient is called an optimized poling angle. Significant enhancement of 60.78% in control performance in PMN-0.42PT is observed at optimum poling angle of 53 degrees whereas, BT-NNb shows 36.75% improvement in control performance at an optimum poling angle 55 degrees. On the other hand, PZT-7A shows a minimum improvement of 15.53% at optimum poling angle 47 degrees.

关键词： Piezoelectric material lumped parameter model active vibration control fuzzy logic controller poling tuning

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Carbon quantum dot regulated electrochemical activation of Co0.03Ni0.97LDH for energy storage

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INORGANIC CHEMISTRY FRONTIERS 2024年第3期11卷 899-911页

作者： Chen, Wenchao Quan, Hongying Chen, Xiangyu Wang, Hua Chen, Dezhi Nanchang Hangkong Univ Key Lab Jiangxi Prov Persistent Pollutants Control Sch Environm & Chem Engn Nanchang 330063 Peoples R China Nanchang Hangkong Univ Sch Mat Sci & Engn Nanchang 330063 Peoples R China Beihang Univ Sch Chem Key Lab Bioinspired Smart Interfacial Sci & Techno Minist Educ Beijing 100191 Peoples R China

The valence and coordination structure of transition metals in electrode materials play a crucial role in the electrochemical energy storage process. However, it is still challenging to modulate the chemical environment of transition metals in multi-metal-based electrode materials because of the presence of charge exchange between the different metal ions. Here, a bimetallic-based electrode material, Co0.03Ni0.97LDH, with low electrochemical activity is transformed into a highly active one through a simple and efficient electrochemical activation process with the assistance of carbon quantum dots (CQDs). It reveals that CQDs can provide a fast charge transfer channel for the unique valence regulation between Co and Ni, resulting in the generation of high concentrations of Co3+ and Ni2+, which is beneficial for upgrading the energy density of the electrode material and mitigating the Jahn-Teller distortion during the conversion of Ni2+/Ni3+. Moreover, the distinctive 5-coordination structures of Co can effectively stabilize the active sites of both Ni2+ and Co3+. The activated CQD-modified Co0.03Ni0.97LDH composites (A-CQD/Co0.03Ni0.97LDH) deliver a high specific capacity of 2408 F g(-1) at 1 A g(-1) and maintain a high capacity retention of 90% after 2000 cycles at 10 A g(-1). The assembled asymmetric supercapacitor and the aqueous Ni-Zn battery show a high energy storage density of 0.25 mW h cm(-2) at a power density of 2.25 mW cm(-2) and 1.44 mW h cm(-2) at 0.72 mW cm(-2), respectively. The impressive results provide a feasible strategy for the rational design of multi-metal-based electrode materials.

关键词： Nanocrystals

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Active flutter control of a bridge-flap system considering aerodynamic interferences in practical considerations

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smart materials AND structures 2022年第6期31卷 065006-065006页

作者： Li, Ke Zhao, Lin Hui, Yi Yang, Qingshan Chen, Zengshun Qian, Guowei Chongqing Univ Minist Educ Key Lab New Technol Construct Cities Mt Area Chongqing 400045 Peoples R China Chongqing Univ Sch Civil Engn Chongqing 400045 Peoples R China Chongqing Key Lab Wind Engn & Wind Energy Utiliza Chongqing 400045 Peoples R China Tongji Univ State Key Lab Disaster Reduct Civil Engn Shanghai 200092 Peoples R China Univ Tokyo Sch Engn Dept Civil Engn Tokyo 1138656 Japan

Designing bridges with spans larger than 2000 m is challenging. One critical problem is that the flutter stability of such bridges is extremely weak. In past studies, actively controlled flaps were found to improve the flutter stability performance. However, in those studies, the deck was always assumed to be an ideal streamlined plate to simplify the aerodynamic interference effect in the deck-flap system. This simplification limits the application of this technique on real projects. To improve the applicability, we adopt a typical bluff body deck to investigate the effect of the active flaps under different wind attack angles. The novelty of this work is the analysis of the aerodynamic interference and resulting control impact considering the application scenario. The tests are conducted through the computational fluid dynamic method. To give intuitive explanations of the aerodynamic interference, the distributed aerodynamic characteristics method is innovatively introduced to quantify the contribution of flap on the flutter stability during the control process. Our results show that the leading flap has a dominant contribution to the flutter stability by inducing the beneficial aerodynamic damping on the deck's leading surfaces. Its optimal phase should be about pi/2 lagging from the deck's torsional motion. In comparison, the effect of the trailing flap is unstable under different wind attack angles. To guarantee a robust control effect, it is suggested that it remains stationary.

关键词： flutter active control aerodynamic interference CFD simulation distributed aerodynamic characteristics

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Optical and electrical characteristics of dome tapered silicon nanowires for efficient photovoltaic solar energy conversion

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Optical and Quantum Electronics 2025年第1期57卷 1-26页

作者： El-Bashar, R. Hameed, Mohamed Farhat O. Abdelhamid, Hamdy Obayya, S.S.A. Cairo University Giza Egypt Centre for Photonics and Smart Materials Zewail City of Science Technology and Innovation October Gardens Giza 6th of October City12578 Egypt Center for Nanotechnology Zewail City of Science Technology and Innovation October Gardens Giza 6th of October City12578 Egypt Mathematics and Engineering Physics Department Faculty of Engineering University of Mansoura Mansoura35516 Egypt Cairo Egypt Electrical Engineering Department College of Engineering and Information Technology Ajman University Ajman United Arab Emirates Zewail City of Science Technology and Innovation October Gardens Giza 6th of October City12578 Egypt Electronics and Communications Engineering Department Faculty of Engineering University of Mansoura Mansoura35516 Egypt

The optical and electrical characteristics of novel dome-shaped nanowires (NWs) are reported for energy harvesting applications. In order to show the superiority of the suggested design, a comparison is made with cylindrical and other tapered nanowires such as conical and horn-shaped NWs. A tapering parameter is introduced to control the NW geometry and its optical and electrical efficiency. Further, the different geometrical parameters are investigated using finite difference time domain to minimize the light reflection and maximize the absorption through the suggested designs. It is evident that the tapering parameter effectively can control the NW-tip geometry to achieve optimum light coupling. The dome-shaped NW design has a good light confinement with better absorption compared to the horn and conical NW structures. This is due to the supported MIE-based mode resonances over a broad wavelength range. Further, the top diameter of the dome-shaped NWs supports more guided modes with high intensity and better light coupling. Besides, the light reflections between the tapered NWs improve the light coupling with the NWs where the optical path length of low frequencies is increased with improved light absorption. Therefore, the reported design with tapering factor of 2.2 achieves an average absorption of 81% with an improvement of 9.5% over the absorption of the conical NWs SC. Further, photo-generated current density and optical efficiency of 37 mA/cm2 and 41% are obtained by the reprted design with an enhancement of 22% and 8.8% compared to conventional cylindrical and conical NWs, respectively. Further, the electrical efficiency is simulated using the finite element method considering the recombination effects. The power conversion efficiency of the dome-shaped array is equal to 15.96%, with an enhancement of 32% and 17.5% relative to cylindrical and conical NWs, respectively. The fine-tapered NW with a dome-shaped design is a crucial step toward realizing highly e

关键词： Domes

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