A comparison of the dynamic properties of transducer adapters for measurement of hand-transmitted vibration

The dynamic characteristics of five types of widely used transducer adapters were compared in terms of vibration transmissibility between an accelerometer on the surface of the gripping area and another within each of the transducer adapters over a frequency range of 25–1250 Hz. Performance was also assessed from the ratio between two human vibration exposure levels, ahv, 1 and ahv, 2, measured using the two accelerometers over nine combinations of grip force and feed force. In this study, vibration transmissibility and ahv ratio of unity are considered. The vibration transmissibility and ahv ratio indicated that the flexible palm adapter provided the best estimate of vibration transmission to the hand. This transducer adapter exhibited the smallest deviation from unity for vibration transmissibility, which was <1.8 per cent over the frequency range, and ahv ratio, which was <4 per cent over nine combinations of grip and feed forces. From the investigation, the flexible palm adapter showed negligible distortion over the frequency range and high applicability, regardless of the gripping condition. The handle-type adapter provided the second-best estimate.

Download Full-text

Characterizing vibration responses of a handheld workpiece and the hand–arm system

Journal of Low Frequency Noise Vibration and Active Control ◽

10.1177/1461348420934617 ◽

2020 ◽

pp. 146134842093461

Author(s):

Xueyan S Xu ◽

Daniel E Welcome ◽

Thomas W McDowell ◽

Christopher Warren ◽

Hansheng Lin ◽

...

Keyword(s):

Resonant Frequency ◽

Resonance Frequency ◽

Grinding Wheel ◽

Vibration Exposure ◽

Apparent Mass ◽

Entire System ◽

Interface Conditions ◽

Feed Force ◽

Vibration Transmissibility ◽

Vibration Responses

The objective of this study is to characterize the vibration responses of a handheld workpiece and the hand–arm system, which is an important step toward identifying and developing effective methods and technologies for controlling the vibration exposures to workers performing the grinding of handheld workpieces. This study established a method for measuring the vibration responses of the entire workpiece–hand–arm system; the vibration exposure of a worker holding and pressing a typical workpiece against a sanding belt or grinding wheel in order to shape the workpiece was simulated. This method was applied to measure the apparent mass and vibration transmissibility of the system under two different feed forces (15 N and 30 N) and six simulated grinding interfaces with different stiffness values. A major resonance was observed in each transmissibility spectrum of the workpiece, which was correlated with the major resonance of the impedance of the entire system. This resonant frequency depended primarily on the workpiece mass and the grinding interface stiffness, but the hand–arm system could substantially affect the resonance magnitude. The feed force also significantly affected the resonance frequency and magnitude. While increasing the feed force increased the overall vibration transmissibility on the hand–arm system, the transmissibility with respect to the workpiece was not significantly affected by the interface conditions. The implications of the results are discussed.

Download Full-text

Vibration Transmission during Manual Wheelchair Propulsion: A Systematic Review

Vibration ◽

10.3390/vibration4020029 ◽

2021 ◽

Vol 4 (2) ◽

pp. 444-481

Author(s):

Ophélie Lariviere ◽

Delphine Chadefaux ◽

Christophe Sauret ◽

Patricia Thoreux

Keyword(s):

Systematic Review ◽

Human Body ◽

Current Knowledge ◽

Vibration Exposure ◽

Wheelchair Propulsion ◽

Simulation Approach ◽

Frequency Range ◽

Vibration Transmission ◽

Manual Wheelchair ◽

Vibration Transmissibility

Manual wheelchair (MWC) propulsion can expose the user to significant vibration. Human body exposure to certain vibrations can be detrimental to health, and a source of discomfort and fatigue. Therefore, identifying vibration exposure and key parameters influencing vibration transmissibility during MWC propulsion is crucial to protect MWC users from vibration risks. For that purpose, a systematic review using PRISMA recommendations was realizedtosynthesizethe current knowledge regarding vibration transmissibility during MWC propulsion. The 35 retrieved articles were classified into three groups: Vibration content, parameters influencing vibration transmission, and vibration transmission modeling. The review highlighted that MWC users experience vibration in the frequency range detrimental/uncomfortable for human vibration transmission during MWC propulsion depends on many parameters and is still scarcely studied and understood. A modeling and simulation approach would be an interesting way to assist physicians in selecting the best settings for a specific user, but many works (modeling, properties identification, etc.) must be done before being effective for clinical and industrial purposes.

Download Full-text

Vibration Exposure and Transmissibility on Dentist’s Anatomy: A Study of Micro Motors and Air-Turbines

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18084084 ◽

2021 ◽

Vol 18 (8) ◽

pp. 4084

Author(s):

Harish Kumar Banga ◽

Pankaj Goel ◽

Raman Kumar ◽

Vikas Kumar ◽

Parveen Kalra ◽

...

Keyword(s):

Research Work ◽

High Amplitude ◽

Vibration Exposure ◽

Body Parts ◽

Descriptive Research ◽

Air Turbine ◽

Test Of Homogeneity ◽

Hand Piece ◽

Vibration Transmissibility ◽

Levene Test

The use of dental hand pieces endanger dentists to vibration exposure as they are subjected to very high amplitude and vibration frequency. This paper has envisaged a comparative analysis of vibration amplitudes and transmissibility during idling and drilling with micro motor (MM) and air-turbine (AT) hand pieces. The study aims to identify the mean difference in vibration amplitudes during idling, explore different grasp forces while drilling with irrigant injection by the dentist, and various vibration transmission of these hand pieces. The study utilized 22 separate frequency resonances on two new and eight used MMs and two new and eight used ATs of different brands by observing the investigator at 16 different dentist clinics. The study adopted a descriptive research design with non–probability sampling techniques for selecting dentists and hand pieces. Statistical methods like Levene Test of Homogeneity, Welch ANOVA, independent t-test, and Games–Howell test were utilized with SPSS version 22 and MS-Excel. The results reveal that vibration amplitudes and vibration transmissibility when measured at position 2 are higher than in another position 1. Vibrations during idling for used MMs are more than AT hand pieces, and the used MM (MUD) and used AT (AUA) hand pieces differ due to their obsolescence and over-usage. Vibration amplitudes increase every time with the tightening of grasping of the hand piece. Vibration amplitudes for each grasping style of MM hand piece differ from all other grasping styles of AT hand pieces. Routine exposure to consistent vibrations has ill physical, mental, and psychological effects on dentists. The used hand pieces more hazardous as compared to newer ones. The study suggests that these hand pieces must be replaced periodically, sufficient to break between two operations, especially after every hand piece usage. Hence, the present research work can be further extended by creating some control groups among dentists and then studying the vibration amplitude exposure of various dental hand pieces and subsequent transmissibility to their body parts.

Download Full-text

The Dynamic Characteristics of Rigid Frame Single-Rib Arch Bridge

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.368-370.1426 ◽

2013 ◽

Vol 368-370 ◽

pp. 1426-1430

Author(s):

Li Xiong Gu ◽

Rong Hui Wang

Keyword(s):

Dynamic Characteristics ◽

Bending Strength ◽

Dynamic Properties ◽

Structural Parameters ◽

Bending Stiffness ◽

Torsional Stiffness ◽

Lateral Stiffness ◽

Arch Bridge ◽

Vertical Stiffness ◽

Rigid Frame

In this paper, by establishing the finite element model to study the dynamic characteristics of rigid frame single-rib arch bridge. By respectively changing structural parameters of the span ratios, and the compressive stiffness of arch, and the bending stiffness of arch, and the bending stiffness of bridge girder, and the layout of boom to find out the regularity of the structure on lateral stiffness, and vertical stiffness, and torsional stiffness as well as dynamic properties, it come out the results of that lateral stiffness of the structure is weaker, and increasing the span ratios and the compressive strength of arch are conducive to the improvement of the overall stiffness, and improving the bending strength of arch and layout of boom are less effect on the overall stiffness and mode shape.

Download Full-text

Dynamic Property Evaluation of a Long-Span Cable-Stayed Bridge (Sutong Bridge) by a Bayesian Method

International Journal of Structural Stability and Dynamics ◽

10.1142/s0219455419400108 ◽

2018 ◽

Vol 19 (01) ◽

pp. 1940010 ◽

Cited By ~ 11

Author(s):

Yan-Chun Ni ◽

Qi-Wei Zhang ◽

Jian-Feng Liu

Keyword(s):

Natural Frequency ◽

Dynamic Characteristics ◽

Structural Damage ◽

Dynamic Properties ◽

Modal Identification ◽

Modal Parameters ◽

Modal Parameter ◽

Cable Stayed Bridge ◽

Long Span ◽

Sutong Bridge

Modal identification aims at identifying the dynamic properties including natural frequency, damping ratio, and mode shape, which is an important step in further structural damage detection, finite element model updating, and condition assessment. This paper presents the work on the investigation of the dynamic characteristics of a long-span cable-stayed bridge-Sutong Bridge by a Bayesian modal identification method. Sutong Bridge is the second longest cable-stayed bridge in the world, situated on the Yangtze River in Jiangsu Province, China, with a total length of 2 088[Formula: see text]m. A short-term nondestructive on-site vibration test was conducted to collect the structural response and determine the actual dynamic characteristics of the bridge before it was opened to traffic. Due to the limited number of sensors, multiple setups were designed to complete the whole measurement. Based on the data collected in the field tests, modal parameters were identified by a fast Bayesian FFT method. The first three modes in both vertical and transverse directions were identified and studied. In order to obtain modal parameter variation with temperature and vibration levels, long-term tests have also been performed in different seasons. The variation of natural frequency and damping ratios with temperature and vibration level were investigated. The future distribution of the modal parameters was also predicted using these data.

Download Full-text

Determination of dynamic properties of elastomers over broad frequency range

Experimental Mechanics ◽

10.1007/bf02320404 ◽

1983 ◽

Vol 23 (2) ◽

pp. 158-164 ◽

Cited By ~ 13

Author(s):

G. M. Smith ◽

R. L. Bierman ◽

S. J. Zitek

Keyword(s):

Dynamic Properties ◽

Frequency Range ◽

Broad Frequency Range

Download Full-text

DYNAMIC CHARACTERISTICS OF THE KAO PING HSI BRIDGE UNDER SEISMIC LOADING WITH FOCUS ON CABLE SIMULATION

International Journal of Structural Stability and Dynamics ◽

10.1142/s0219455411004531 ◽

2011 ◽

Vol 11 (06) ◽

pp. 1179-1199 ◽

Cited By ~ 5

Author(s):

MING-YI LIU ◽

LI-CHIN LIN ◽

PAO-HSII WANG

Keyword(s):

Finite Element ◽

Dynamic Characteristics ◽

Hybrid Method ◽

Dynamic Properties ◽

Seismic Loading ◽

Cable System ◽

Initial Shape ◽

Element Computation ◽

Southern Taiwan ◽

Finite Element Computation

The objective of this study is to thoroughly investigate the dynamic characteristics of the Kao Ping Hsi Bridge located in southern Taiwan. A one-element cable system (OECS) and a multi-element cable system (MECS) are presented for simulating the dynamic properties of the cables of the bridge. By a finite element computation procedure, the initial shape, modal, and seismic analyses are conducted for the bridge using either the OECS or MECS model. A hybrid method combining both the two-loop iteration and the catenary function is proposed to determine the initial shapes using the MECS model. Convergent and smooth initial shapes can be obtained using such a method. The results indicate that the OECS model can yield solution in an efficient way, whereas the MECS model should be used if solutions of greater accuracy are desired.

Download Full-text

Ensemble of DNA Kinks

EPJ Web of Conferences ◽

10.1051/epjconf/201922403005 ◽

2019 ◽

Vol 224 ◽

pp. 03005 ◽

Cited By ~ 1

Author(s):

Ludmila V. Yakushevich ◽

Larisa A. Krasnobaeva

Keyword(s):

Hydrogen Bonds ◽

Dynamic Characteristics ◽

Dynamic Properties ◽

Double Helix ◽

Statistical Properties ◽

Dna Molecule ◽

Open States

The DNA open states, which are locally unwound regions of the double helix within which hydrogen bonds between complementary nitrous bases are broken, are often modeled as quasiparticles – DNA kinks. Most of the works on the DNA kinks are devoted to the studies of their dynamic properties, as well as their role in the functioning of the molecule. However, if not one but N open states are formed in the DNA molecule it is reasonable to consider the problem of the statistics of the ensemble of N DNA kinks. The statistical properties of such an ensemble are still poorly understood. In the present work, we study these properties applying new data on the dynamic characteristics of DNA kinks.

Download Full-text

Dynamic Properties of Clean Sand Modified with Granulated Rubber

Advances in Civil Engineering ◽

10.1155/2018/5209494 ◽

2018 ◽

Vol 2018 ◽

pp. 1-11 ◽

Cited By ~ 7

Author(s):

Dervis Volkan Okur ◽

Seyfettin Umut Umu

Keyword(s):

Shear Modulus ◽

Dynamic Characteristics ◽

Dynamic Properties ◽

Damping Ratio ◽

Relative Size ◽

Cyclic Behavior ◽

Damping Capacity ◽

Resonant Column ◽

Strain Dependent

Waste automobile tires are used as additives or replacements instead of traditional materials in civil engineering works. In geotechnical engineering, tires are shredded to certain sizes and mixed with soil, especially used as backfill material behind retaining walls or fill material for roadway embankments. Compared to soil, rubber has high damping capacity and low shear modulus. Therefore, it requires the determination of the dynamic characteristics of rubber/soil mixtures. In this paper, the cyclic behavior of recycled tire rubber and clean sand was studied, considering the effects of the amount and particle size of the rubber and confining stresses. A total of 40 stress-controlled tests were performed on an integrated resonant column and dynamic torsional shear system. The effects of the relative size and proportion of the rubber on the dynamic characteristics of the mixtures are discussed. The dynamic properties, such as the maximum shear modulus, strain-dependent shear modulus, and damping ratio, are examined. For practical purposes, simple empirical relationships were formulated to estimate the maximum shear modulus and the damping ratio. The change in the shear modulus and damping ratio with respect to shear strain with 5% of rubber within the mixture was found to be close to the behavior of clean sand.

Download Full-text