Article
Engineering, Industrial
Xiaolu Zhang, Qingyu Zhang, Yuejuan Li, Chi Liu, Yi Qiu
Summary: Increasing the thickness of foam at the seat pan and backrest can reduce the resonance frequency of the seat transmissibilities with fore-and-aft vibration. Altering the thickness of foam at the seat pan is more effective than changing that at the backrest.
APPLIED ERGONOMICS
(2021)
Article
Acoustics
Ehsan Davoodi, Pedram Safarpour, Mahdi Pourgholi, Mostafa Khazaee
Summary: This article presents a seat suspension based on negative stiffness structure to reduce vibration transmitted to helicopter pilots. By studying the impact of parameters on system performance, design parameters are determined to make the system respond simultaneously as a negative stiffness structure in both directions.
JOURNAL OF VIBRATION AND CONTROL
(2022)
Article
Acoustics
Qiao Luo, Yansong He, Zhifei Zhang, Kaizhan Gao
Summary: The vibration characteristics of car seats directly affect the ride comfort. This study investigates the influence of foam thickness and hardness on the vibration characteristics of seat cushions with different excitation magnitudes.
JOURNAL OF LOW FREQUENCY NOISE VIBRATION AND ACTIVE CONTROL
(2023)
Article
Engineering, Mechanical
Qicheng Zhang, Xindi Yu, Fabrizio Scarpa, David Barton, Yunpeng Zhu, Zi-Qiang Lang, Dayi Zhang
Summary: This study proposes a new dynamic poroelastic model to describe the vibration transmissibility of auxetic polyurethane (PU) foams. Experimental tests and data regression are conducted to determine the permeability and viscoelasticity of the foams, and it is found that different foams have different moduli along different directions.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2022)
Article
Mechanics
Yanqi Liu, Wen Ji, Erjie Deng, Xin Wang, Chunfang Song
Summary: This study presents a two degree-of-freedom quasi-zero stiffness (QZS) vibration isolator based on the anti-resonance characteristics of a multi-degree-of-freedom system. Nonlinear inclined springs (NIS) are used to achieve the nonlinear stiffness, with both linear and cubic stiffness terms. The effects of various mechanical and structural parameters on the stiffness characteristics are analyzed, and the dynamic response and force transmissibility are numerically discussed. The results show that the system can achieve smaller stiffness and wider low-stiffness range near equilibrium position by using smaller structural parameters and nonlinear inclined springs with softening stiffness.
MECHANICS BASED DESIGN OF STRUCTURES AND MACHINES
(2023)
Article
Construction & Building Technology
Tao Liu, Aiqun Li, Hengyuan Zhang
Summary: Compared with the linear isolation system, the quasi-zero-stiffness (QZS) nonlinear isolation system has better low-frequency vibration isolation performance due to its high static stiffness and low dynamic stiffness. To optimize the isolation performance, a new isolation device based on the parallel connection of oblique springs and vertical springs was proposed, which can expand the interval of quasi-zero-stiffness through parameter optimization design. The vibration isolation performance of the QZS system was analyzed and compared with the linear system through a shaking table test.
STRUCTURAL CONTROL & HEALTH MONITORING
(2023)
Article
Chemistry, Multidisciplinary
Wu Pan-Zagorski, Peter W. Johnson, Missy Pereny, Jeong Ho Kim
Summary: This study evaluated automotive seats with different foam firmnesses to understand how foam firmness affects seat vibration performance and perceived dynamic comfort. The results showed that foam firmness significantly affected whole body vibration and self-reported comfort.
APPLIED SCIENCES-BASEL
(2022)
Article
Engineering, Mechanical
Shihua Zhou, Yulin Liu, Zeyu Jiang, Zhaohui Ren
Summary: A bio-inspired embedded X-shaped vibration isolation (BIE-XVI) structure is proposed in this paper to improve the performance of passive vibration isolation system. By considering muscle/tendon contractile functions, joint rotational friction and connecting rod mass, the structure provides better vibration isolation properties. The effects of key parameters on frequency response characteristics and vibration isolation range are thoroughly analyzed, and the structure can achieve quasi-zero-stiffness property for vibration isolation.
NONLINEAR DYNAMICS
(2022)
Article
Engineering, Industrial
Xiaolu Zhang, Peijin Yu, Yuejuan Li, Yi Qiu, Chao Sun, Zunming Wang, Chi Liu
Summary: The study quantified the effect of inclined seats, either foamed or rigid, on transmissibilities, with the backrest angle found to have a stronger impact than the seat pan angle.
Article
Engineering, Mechanical
Shihua Zhou, Bowen Hou, Lisheng Zheng, Pingzhen Xu, Tianzhuang Yu, Zhaohui Ren
Summary: A novel bio-inspired vibration isolation-absorption (BIVIA) system is presented, inspired by the anti-vibration and shock absorption properties of the ostrich. The system is designed to achieve wideband vibration isolation bandwidth, low-frequency/ultra-low-frequency vibration isolation, and high stability using a toe-leg-spine coupling structure. The influences of different parameters on the performance of the BIVIA system are discussed, and it is found that coupled vibration isolation-absorption structures can achieve high loading capacity and extended quasi-zero stiffness (QZS) zone. The adjustable vibration isolation-absorption performance of the BIVIA structure makes it a practical method for bio-inspired vibration isolation, suitable for engineering and manufacturing applications.
NONLINEAR DYNAMICS
(2023)
Article
Engineering, Industrial
Mael Amari, Nellie Perrin
Summary: Mobile machinery operators are exposed to whole-body vibrations and unfavourable body posture, which may have adverse effects on the spine. This study provides measurements of apparent mass and seat-to-head transmissibility in different postures, aiming to understand the effects of vibration on the spine.
Article
Engineering, Mechanical
Yiming Cao, Weijiao Chen, Hui Ma, Hui Li, Bing Wang, Li Tan, Xin Wang, Qingkai Han
Summary: In this study, a novel nonlinear clamp model with four degrees of freedom is proposed for the metal rubber clamp in pipeline system. The model is verified and its effectiveness is demonstrated through modal tests and vibration response experiments. Different clamp types are also tested to evaluate their supporting performance. The numerical results are consistent with the experimental data, showing that the proposed model effectively captures the nonlinear effects of the pipeline system and enables more accurate prediction of vibration responses.
NONLINEAR DYNAMICS
(2023)
Article
Engineering, Industrial
Delphine Chadefaux, Alex P. Moorhead, Pietro Marzaroli, Stefano Marelli, Enrico Marchetti, Marco Tarabini
Summary: WBV is an occupational hazard affecting employees working with transportation, construction or heavy machinery. ISO identified WBV exposure limits based on vibration transmissibility and apparent mass studies. In our study, we found that the transmission rates vary during stationary and propelled walking, indicating a need for adjusting ISO standards for active workers.
APPLIED ERGONOMICS
(2021)
Article
Engineering, Multidisciplinary
Ping Liu, MinQiang Meng, Yang Xiao, HanLong Liu, Gui Yang
Summary: Polyurethane foam adhesive (PFA) has been introduced as an alternative stabilizer in geotechnical applications, but its dynamic properties in reinforced soils are not well understood. Experimental results showed that PFA content, confining pressure, and consolidation stress ratio significantly affect the shear modulus and damping ratio of soils, while the loading frequency has negligible effect. A modified hyperbolic empirical model can predict the relationship between shear modulus and shear strain, with proposed upper and lower bounds for damping ratio.
SCIENCE CHINA-TECHNOLOGICAL SCIENCES
(2021)
Article
Engineering, Mechanical
Junhan An, Guoping Chen, Xi Deng, Chen Xi, Tao Wang, Huan He
Summary: This paper examines the dynamic phenomenon of a pneumatic QZS isolator with mistuned mass and analyzes the amplitude-frequency relationship and force transmissibility. The results show that, in the case of a large mass mistuning, the system exhibits possible response periods and chaos phenomena. Mass detuning leads to a more complex nonlinear response of the QZS isolator, and the dynamic response becomes more sensitive to changes in parameters such as external excitation frequency, amplitude, and damping ratio. These findings are helpful for improving the structure of the pneumatic QZS vibration isolator and determining the applicable working frequency.
NONLINEAR DYNAMICS
(2022)
Article
Pediatrics
Renu Arya, Georgina Williams, Anna Kilonback, Martin Toward, Michael Griffin, Peter S. Blair, Peter Fleming
ARCHIVES OF DISEASE IN CHILDHOOD-FETAL AND NEONATAL EDITION
(2017)
Article
Engineering, Industrial
Zhen Zhou, Michael J. Griffin
Article
Engineering, Industrial
Khairil Anas Md Rezali, Michael J. Griffin
Article
Engineering, Industrial
Zhen Zhou, Michael J. Griffin
Article
Engineering, Civil
Weidong Gong, Michael J. Griffin
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART F-JOURNAL OF RAIL AND RAPID TRANSIT
(2018)
Article
Public, Environmental & Occupational Health
Ying Ye, Michael J. Griffin
INTERNATIONAL ARCHIVES OF OCCUPATIONAL AND ENVIRONMENTAL HEALTH
(2018)
Article
Biophysics
Chi Liu, Yi Qiu, Michael J. Griffin
JOURNAL OF BIOMECHANICS
(2017)
Article
Engineering, Industrial
Khairil Anas Md Rezali, Michael J. Griffin
Article
Engineering, Industrial
Giulia Patelli, Miyuki Morioka, Michael J. Griffin
Article
Engineering, Industrial
Chi Liu, Michael J. Griffin
INTERNATIONAL JOURNAL OF INDUSTRIAL ERGONOMICS
(2018)
Article
Engineering, Industrial
Giulia Patelli, Michael J. Griffin
APPLIED ERGONOMICS
(2019)
Article
Engineering, Industrial
James J. Arnold, Michael J. Griffin
Article
Engineering, Industrial
Guangtai Zheng, Yi Qiu, Michael J. Griffin
INTERNATIONAL JOURNAL OF INDUSTRIAL ERGONOMICS
(2019)
Article
Engineering, Biomedical
Hatice Mujde Ayik, Michael J. Griffin
JOURNAL OF APPLIED BIOMECHANICS
(2019)
Article
Engineering, Civil
Chi Liu, David Thompson, Michael J. Griffin, Mani Entezami
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART F-JOURNAL OF RAIL AND RAPID TRANSIT
(2020)