Article
Engineering, Mechanical
Hui Gao, Hao Wang, Jian Li, Jianxiao Mao, Zhihao Wang
Summary: A novel negative stiffness inerter damper (NSID) is proposed in this study to improve the control performance of stay cables. The NSID utilizes the damping enhancement of negative stiffness and inerter for cable vibration control. The study explores the modal behavior of the cable based on optimum parameters of the NSID and demonstrates the principle and conditions of the NSID for cable vibration control. The NSID performs better than other dampers in mitigating cable vibrations.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2022)
Article
Engineering, Mechanical
Hui Gao, Hao Wang, Jian Li, Jianxiao Mao, Zhihao Wang
Summary: A novel negative stiffness inerter damper (NSID) is proposed to improve the control performance of stay cables. The NSID utilizes the damping enhancement of negative stiffness and inerter for cable vibration control. The modal behavior of the cable based on optimum parameters of the NSID is explored, and the damping enhancement principle and conditions are demonstrated. The control efficacy of the NSID is evaluated, showing better performance than other dampers in mitigating multi-mode cable vibrations.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2022)
Article
Nanoscience & Nanotechnology
N. S. Saravana Jothi, A. Hunt
Summary: Metamaterials are artificially structured materials with unique properties that do not exist in nature. Mechanical metamaterials aim to overcome limitations by embedding actuation into the unit elements, enabling control of material properties and mechanical states. This study proposes and investigates an active mechanical metamaterial concept that can actively control force and deformation distribution within its lattice.
Article
Mechanics
Xiaojun Tan, Lianchao Wang, Shaowei Zhu, Shuai Chen, Bing Wang, Muamer Kadic
Summary: This study demonstrates how to improve the mechanical properties of cylindrical negative stiffness structures by introducing fillers. Different types of fillers have different effects: linear elastic fillers can enhance energy absorption but degrade energy dissipation, visco-hyperelastic fillers can enhance energy dissipation regardless of snap-back behavior, and true negative stiffness fillers can improve energy dissipation and decrease strength simultaneously.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2022)
Article
Engineering, Mechanical
Xu Chen, Jinglei Zhao, Jie Deng, Yan Jing, Huayan Pu, Jun Luo
Summary: Acoustic black holes (ABHs) have attracted increasing attention in the field of vibration suppression, sound radiation control and energy harvesting. However, they are unable to be triggered at low frequencies. By combining an ABH beam with a negative stiffness element, a novel method to enhance vibration reduction at low frequencies is proposed. The results show that the proposed NS-ABH beam can achieve remarkable vibration reduction below the cut-on frequency without sacrificing the ABH effect at higher frequency.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2023)
Article
Engineering, Civil
Hui Gao, Zhihao Wang, Junfeng Jia, Zhipeng Cheng
Summary: In this study, a new negative stiffness electromagnetic tuned inerter damper (NSETID) is proposed to suppress vortex-and rain-wind-induced vibrations of long stay cables. The non-dimensional analytical equations and optimum parameters of the NSETID are developed, taking into consideration influences of cable sag and flexural stiffness. The superior damping enhancement capabilities of the NSETID in mitigating single-mode and multi-mode cable vibrations are highlighted.
ENGINEERING STRUCTURES
(2023)
Article
Physics, Applied
J. Pribosek, M. Eder
Summary: This study presents a resonant torsional micro-mirror with all-piezoelectric driving and tunable spring stiffness. The stiffness modulation has practical applications for tuning the resonance frequency and increasing the optical scan angle.
APPLIED PHYSICS LETTERS
(2022)
Article
Acoustics
Licheng Jia, Lei Shi, Chongbin Liu, Chengliang Sun, Guoqiang Wu
Summary: This article investigates the impact of top electrode design on transmitting sensitivity of piezoelectric micromachined ultrasonic transducers (PMUTs). Two typical top electrode designs, inner electrode (IE) and outer electrode (OE), were studied and it was found that the OE design showed higher transmitting velocities due to higher quality factor (Q) and resonant frequency, leading to increased acoustic pressure output and higher transmitting sensitivity.
IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL
(2021)
Article
Engineering, Mechanical
Ying Zhang, Qinghua Liu, Yaguo Lei, Junyi Cao, Wei-Hsin Liao
Summary: This paper proposes a compact magnetic Halbach high negative stiffness isolator to improve low-frequency isolation performance in high static support occasions by reducing size and weight. The magnetic stiffness model is derived and the dynamic equation is established to investigate the transmissibility for different magnetic arrays. Numerical and experimental results demonstrate the effectiveness of the proposed isolator under low-frequency and random excitations.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2023)
Article
Chemistry, Multidisciplinary
Zhangbin Feng, Ke Wang, Yukang Liu, Biao Han, Deng-Guang Yu
Summary: In this study, core-sheath structure fibers composed of PVDF and NPs as the shell layer and PCL as the core layer were prepared using electrospinning. The addition of PVDF and NPs increased the polar phase of the fibers, and PCL improved their mechanical properties. The core-sheath structure fibers demonstrated enhanced mechanical and piezoelectric properties, making them suitable for wearable electronics applications.
Article
Computer Science, Information Systems
Wu-Sung Yao, Chun-Yi Lin
Summary: This paper investigates the dynamic stiffness of the quadcopter control system and proposes a repetitive controller to reduce the vibration effect by enhancing the direct dynamic stiffness and quadrature dynamic stiffness. Simulated and experimental results demonstrate that the system with the repetitive controller has larger magnitudes of direct dynamic stiffness and smoother quadrature dynamic stiffness compared to the system without the repetitive controller, while also having lower loss factor.
Article
Chemistry, Multidisciplinary
Jingyan Liu, Shi Zeng, Mingrui Zhang, Juan Xiong, Haoshuang Gu, Zhao Wang, Yongming Hu, Xianghui Zhang, Yi Du, Long Ren
Summary: Introducing liquid metal nanodroplets into the polymer matrix significantly improves the performance and reliability of piezoelectric composites. By creating liquid-solid/conductive-dielectric interfaces, a giant performance improvement is achieved, with a nearly 1000% boost in output voltage and 270% increase in piezoelectric coefficient. This study opens up new possibilities for developing high-performance piezoelectric composite-based devices.
Article
Engineering, Electrical & Electronic
Sajad Hadidi, Alireza Hassanzadeh
Summary: This article presents a novel high-sensitivity vibration sensor based on the piezoelectric combo effect. The sensor combines direct and inverse piezoelectric effects for increased sensitivity. Experimental results show that the proposed sensor has high sensitivity and good linearity, and it outperforms the bimorph sensor in terms of sensitivity by about 3.6 times.
IEEE SENSORS JOURNAL
(2023)
Article
Thermodynamics
X. L. Zhong, K. C. Chan, S. C. Fu, L. Q. Wang, Christopher Y. H. Chao
Summary: Piezoelectric fan cooling is receiving increased attention for its compact size and high energy efficiency. This study investigates the impact of fan location and channel configuration on heat transfer performance. By adjusting the fan position, a higher streamwise velocity is achieved, leading to improved heat transfer. Inserting a fan into the channel results in a 55% enhancement of the Nusselt number compared to natural convection. Additionally, both expansion and contraction configurations enhance heat transfer, with the optimal configuration providing an additional 10% enhancement. Flow visualization and velocity measurements reveal that the contraction configuration boosts streamwise velocity and generates a jet flow pattern, while the expansion configuration promotes more vortices and spanwise mixing.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Engineering, Geological
H. P. Zhu, Z. A. Tang, H. Luo
Summary: The study focuses on achieving simultaneous reduction in isolator displacement and liquid sloshing response of a base-isolated liquid storage tank by utilizing negative-stiffness dampers (NSDs). The use of NSDs, designed using an equivalent linearization technique, is shown to be effective in improving seismic performance of base-isolated storage tanks. Nonlinear response history analyses demonstrate the benefits of the proposed method in reducing base shear and sloshing responses without compromising isolator displacements.
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
(2023)
Article
Mechanics
H. Kalathur, T. M. Hoang, R. S. Lakes, W. J. Drugan
JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME
(2014)
Article
Physics, Condensed Matter
Bryan Rodriguez, Harsha Kalathur, Roderic Lakes
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2014)
Article
Instruments & Instrumentation
H. Kalathur, R. S. Lakes
SMART MATERIALS AND STRUCTURES
(2013)
