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Nawayseh N, AlBaiti S. Vibration transmitted to the hands of power drill operators: Effect of arm posture and type of drilled material. Proc Inst Mech Eng H 2023:9544119231171211. [PMID: 37096367 DOI: 10.1177/09544119231171211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
Abstract
This study investigated the effect of the arm posture and the type of material on the vibration measured at the hands during drilling operation. An experiment was conducted using three different materials (concrete, steel, and wood) and two different arm postures characterized as 90° and 180° angle between the upper arm and forearm. Six male subjects stood on a force platform to measure and control the feed force during the drilling operation. The vibration was measured at the interface between the drill and both hands. The results showed that the effect of arm posture was dependent on the type of material being drilled. For example, drilling in concrete yielded higher frequency-weighted acceleration with the 90° arm posture than the 180° posture while drilling in wood showed an opposite trend. The results tend to suggest no correlation between the material hardness and the vibration at the hands. Higher vibration was also observed at the right hand than the left hand. It is recommended to not use the vibration emission data reported by manufacturers of power tools to evaluate incidences of hand-arm vibration syndrome (HAVS) but to rely on real measurements taken in the field under typical operating conditions.
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Affiliation(s)
- Naser Nawayseh
- Department of Mechanical and Nuclear Engineering, College of Engineering, University of Sharjah, Sharjah, UAE
| | - Saleh AlBaiti
- Department of Industrial Engineering and Engineering Management, College of Engineering, University of Sharjah, Sharjah, UAE
- Sustainable Engineering Asset Management Research Group (SEAM), University of Sharjah, Sharjah, UAE
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Abstract
Olive harvesting is the most expensive cultivation operation in areas where full mechanization is not possible due to structural conditions such as low tree density, old trees, irregular spacing, and terraced fields, which are very frequent in many small Italian farms. Under these conditions the use of hand-held vibrating harvesters is quite wide spread, because they are capable of approximately three times the productivity of workers using manual harvesting methods. Unfortunately, the use of these machines exposes the operators to hand-arm vibration risk and acceleration values are affected by several factors, including harvester kinematics, rod material and geometry, and load conditions. In this study several models of electrical portable harvesters, obtained by combining six harvester heads and four rods (one telescopic), were tested under idling and load conditions, measuring acceleration values on the rod, near the hand positions. Assuming the use of the machinery for 4 h per day, the result is a level of daily vibration exposure A(8) for the most exposed hand ranging from about 11 to 40 m/s2, much higher than the daily exposure limit value of 5 m/s2 stated by the European Directive 2002/44/EC. With the same harvester head, reduction in vibration may be achieved by using carbon fiber rods rather than aluminum ones or by increasing the rod diameter. The most significant reduction is achievable by designing harvester heads whose kinematics inherently incorporate oscillation compensation.
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Md Rezali KA, Griffin MJ. Transmission of vibration through glove materials: effects of contact force. ERGONOMICS 2018; 61:1246-1258. [PMID: 29628001 DOI: 10.1080/00140139.2018.1462407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 03/29/2018] [Indexed: 06/08/2023]
Abstract
This study investigated effects of applied force on the apparent mass of the hand, the dynamic stiffness of glove materials and the transmission of vibration through gloves to the hand. For 10 subjects, 3 glove materials and 3 contact forces, apparent masses and glove transmissibilities were measured at the palm and at a finger at frequencies in the range 5-300 Hz. The dynamic stiffnesses of the materials were also measured. With increasing force, the dynamic stiffnesses of the materials increased, the apparent mass at the palm increased at frequencies greater than the resonance and the apparent mass at the finger increased at low frequencies. The effects of force on transmissibilities therefore differed between materials and depended on vibration frequency, but changes in apparent mass and dynamic stiffness had predictable effects on material transmissibility. Depending on the glove material, the transmission of vibration through a glove can be increased or decreased when increasing the applied force. Practitioner summary: Increasing the contact force (i.e. push force or grip force) can increase or decrease the transmission of vibration through a glove. The vibration transmissibilities of gloves should be assessed with a range of contact forces to understand their likely influence on the exposure of the hand and fingers to vibration.
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Affiliation(s)
- Khairil Anas Md Rezali
- a Human Factors Research Unit, Institute of Sound and Vibration Research , University of Southampton , Southampton , UK
- b Faculty of Engineering, Department of Mechanical and Manufacturing Engineering , Universiti Putra Malaysia , Serdang , Malaysia
| | - Michael J Griffin
- a Human Factors Research Unit, Institute of Sound and Vibration Research , University of Southampton , Southampton , UK
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Fattorini L, Tirabasso A, Lunghi A, Di Giovanni R, Sacco F, Marchetti E. Muscular forearm activation in hand-grip tasks with superimposition of mechanical vibrations. J Electromyogr Kinesiol 2015; 26:143-8. [PMID: 26597087 DOI: 10.1016/j.jelekin.2015.10.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 09/09/2015] [Accepted: 10/27/2015] [Indexed: 10/22/2022] Open
Abstract
The purpose of this paper is to evaluate the muscular activation of the forearm, with or without vibration stimuli at different frequencies while performing a grip tasks of 45s at various level of exerted force. In 16 individuals, 9 females and 7 males, the surface electromyogram (EMG) of extensor carpi radialis longus and the flexor carpi ulnari muscles were assessed. At a short latency from onset EMG, RMS and the level of MU synchronization were assessed to evaluate the muscular adaptations. Whilst a trend of decay of EMG Median frequency (MDFd) was employed as an index of muscular fatigue. Muscular tasks consists of the grip of an instrumented handle at a force level of 20%, 30%, 40%, 60% of the maximum voluntary force. Vibration was supplied by a shaker to the hand in mono-frequential waves at 20, 30, 33 and 40Hz. In relation to EMG, RMS and MU synchronization, the muscular activation does not seem to change with the superimposition of the mechanical vibrations, on the contrary a lower MDFd was observed at 33Hz than in absence of vibration. This suggests an early muscular fatigue induced by vibration due to the fact that 33Hz is a resonance frequency for the hand-arm system.
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Affiliation(s)
- L Fattorini
- Sapienza Università di Roma, Department of Physiology and Pharmacology "V. Erspamer", Italy.
| | - A Tirabasso
- National Institute for Insurance Against Accidents at Work, Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, Italy
| | - A Lunghi
- National Institute for Insurance Against Accidents at Work, Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, Italy
| | - R Di Giovanni
- National Institute for Insurance Against Accidents at Work, Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, Italy
| | - F Sacco
- National Institute for Insurance Against Accidents at Work, Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, Italy
| | - E Marchetti
- Sapienza Università di Roma, Department of Physiology and Pharmacology "V. Erspamer", Italy; National Institute for Insurance Against Accidents at Work, Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, Italy
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Singh J, Khan AA. Effect of coating over the handle of a drill machine on vibration transmissibility. APPLIED ERGONOMICS 2014; 45:239-246. [PMID: 23642474 DOI: 10.1016/j.apergo.2013.04.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2012] [Revised: 11/19/2012] [Accepted: 04/07/2013] [Indexed: 06/02/2023]
Abstract
This study was to see the effect of different coatings on the handle of hand-held drilling machines. Out of five different handles chosen for this study, including one handle uncoated. Root mean square (rms) values of the vibration levels (acceleration) were recorded at the surface of handle and wrist of the operators. Results showed that maximum vibrations were reduced by coating of handle coated with rubber sheet and Rexene (H4) followed by handle coated with cotton sandwiched between jeans cloth (H5). Equivalent vibrations transmitted through coating of handles coated with sponge and velvet (H2) and jute and cotton (H3) were of almost same magnitude and these two coated handles were able to reduce least vibration transmitted. Transmissibility of vibrations along dominant (Z) direction was analyzed using ANOVA. Results showed that coating on handles significantly affected vibration transmitted in Z direction. Vibration transmissibility ratios were found to be 0.354, 0.571, 0.408, 0.4326, and 0.3555 for handles H1, H2, H3, H4 and H5 respectively.
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Affiliation(s)
- Jagvir Singh
- Department of Mechanical Engineering, Aligarh Muslim University, Aligarh-202002, UP, India.
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Dong RG, Welcome DE, McDowell TW, Wu JZ. Modeling of the biodynamic responses distributed at the fingers and palm of the hand in three orthogonal directions. JOURNAL OF SOUND AND VIBRATION 2013; 232:1125-1140. [PMID: 26609187 PMCID: PMC4656148 DOI: 10.1016/j.jsv.2012.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The objectives of this study were to develop models of the hand-arm system in the three orthogonal directions (xh, yh , and zh ) and to enhance the understanding of the hand vibration dynamics. A four-degrees-of-freedom (DOF) model and 5-DOF model were used in the simulation for each direction. The driving-point mechanical impedances distributed at the fingers and palm of the hand reported in a previous study were used to determine the parameters of the models. The 5-DOF models were generally superior to the 4-DOF models for the simulation. Hence, as examples of applications, the 5-DOF models were used to predict the transmissibility of a vibration-reducing glove and the vibration transmissibility on the major substructures of the hand-arm system. The model-predicted results were also compared with the experimental data reported in two other recent studies. Some reasonable agreements were observed in the comparisons, which provided some validation of the developed models. This study concluded that the 5-DOF models are acceptable for helping to design and analyze vibrating tools and anti-vibration devices. This study also confirmed that the 5-DOF model in the zh direction is acceptable for a coarse estimation of the biodynamic responses distributed throughout the major substructures of the hand-arm system. Some interesting phenomena observed in the experimental study of the biodynamic responses in the three directions were also explained in this study.
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Affiliation(s)
- Ren G. Dong
- Corresponding author. Tel.: +1 304 285 6332; fax: +1 304 285 6265. (R.G. Dong)
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Krajnak K, Waugh S, Johnson C, Miller R, Kiedrowski M. Vibration disrupts vascular function in a model of metabolic syndrome. INDUSTRIAL HEALTH 2009; 47:533-542. [PMID: 19834263 DOI: 10.2486/indhealth.47.533] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Vibration-induced white finger (VWF) is a disorder seen in workers exposed to hand-transmitted vibration, and is characterized by cold-induced vasospasms and finger blanching. Because overweight people with metabolic syndrome are pre-disposed to developing peripheral vascular disorders, it has been suggested that they also may be at greater risk of developing VWF if exposed to occupational vibration. We used an animal model of metabolic syndrome, the obese Zucker rat, to determine if metabolic syndrome alters vascular responses to vibration. Tails of lean and obese Zucker rats were exposed to vibration (125 Hz, 49 m/s(2) r.m.s.) or control conditions for 4 h/d for 10 d. Ventral tail arteries were collected and assessed for changes in gene expression, levels of reactive oxygen species (ROS) and for responsiveness to vasomodulating factors. Vibration exposure generally reduced the sensitivity of arteries to acetylcholine (ACh)-induced vasodilation. This decrease in sensitivity was most apparent in obese rats. Vibration also induced reductions in vascular nitric oxide concentrations and increases in vascular concentrations of ROS in obese rats. These results indicate that vibration interferes with endothelial-mediated vasodilation, and that metabolic syndrome exacerbates these effects. These findings are consistent with idea that workers with metabolic syndrome have an increased risk of developing VWF.
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Affiliation(s)
- Kristine Krajnak
- Engineering and Controls Technology Branch, National Institute for Occupational Safety and Health, 1095 Willowdale Rd, Morgantown, WV 26505, USA.
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Aldien Y, Marcotte P, Rakheja S, Boileau PE. Mechanical impedance and absorbed power of hand-arm under x(h)-axis vibration and role of hand forces and posture. INDUSTRIAL HEALTH 2005; 43:495-508. [PMID: 16100926 DOI: 10.2486/indhealth.43.495] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The biodynamic responses of the hand-arm system under x(h)-axis vibration are investigated in terms of the driving point mechanical impedance (DPMI) and absorbed power in a laboratory study. For this purpose, seven healthy male subjects are exposed to two levels of random vibration in the 8-1,000 Hz frequency range, using three instrumented cylindrical handles of different diameters (30, 40 and 50 mm), and different combinations of grip (10, 30 and 50 N) and push (0, 25 and 50 N) forces. The experiments involve grasping the handle while adopting two different postures, involving elbow flexion of 90 degrees and 180 degrees, with wrist in the neutral position for both postures. The analyses of the results revealed peak DPMI magnitude and absorbed power responses near 25 Hz and 150 Hz, for majority of the test conditions considered. The frequency corresponding to the peak response increased with increasing hand forces. Unlike the absorbed power, the DPMI response was mostly observed to be insensitive to variations in the excitation magnitude. The handle diameter revealed obvious effects on the DPMI magnitude, specifically at frequencies above 250 Hz, which was not evident in the absorbed power due to relatively low velocity at higher frequencies. The influence of hand forces was also evident on the DPMI magnitude response particularly at frequencies. above 100 Hz, while the effect of hand-arm posture on the DPMI magnitude was nearly negligible. The magnitude of power absorbed within the hand and arm was observed to be strongly dependent upon the excitation level over the entire frequency range, while the influence of hand-arm posture on the total absorbed power was observed to be important. The effect of variations in the hand forces on the absorbed power was relatively small for the bent elbow posture, while an increase in either the grip or the push force coupled with the extended arm posture resulted in considerably higher energy absorption. The results suggested that the handle size, hand-arm posture and hand forces, produce coupled effect on the biodynamic response of the hand-arm system.
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Affiliation(s)
- Yasser Aldien
- CONCAVE Research Center, Concordia University 1455 de Maisonneuve West, Montreal, QC, 1M8 H3G Canada
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Dong RG, Wu JZ, Welcome DE. Recent advances in biodynamics of human hand-arm system. INDUSTRIAL HEALTH 2005; 43:449-71. [PMID: 16100922 DOI: 10.2486/indhealth.43.449] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The biodynamics of human hand-arm system is one of the most important foundations for the measurement, evaluation, and risk assessment of hand-transmitted vibration (HTV) exposure. This paper presents a new conceptual model relating factors influencing cause-effect relationships for HTV exposure, a new study strategy, and a comprehensive review of the recent advances in the biodynamics closely associated with HTV exposure. The review covers the following five aspects: theoretical modeling of biodynamic responses, vibration transmissibility, driving-point biodynamic responses, evaluation of anti-vibration gloves, and applied forces. This review finds that some significant advances in each of these aspects have been achieved in the recent years. Several important issues and problems in the biodynamic measurement have been identified and resolved, which has significantly helped improve the reliability and accuracy of the experimental data. The results reported in recent years suggest that, from the point of view of biodynamics, the frequency weighting specified in ISO 5349-1 (2001) overestimates the low frequency effect but underestimates the high frequency effect on the fingers and hand. The major problems, issues, and topics for further studies are also outlined in this paper. It is anticipated that the further studies of the biodynamics of the system will eventually lead to establishment of a robust vibration exposure theory. Although this review focuses on the biodynamics of the hand-arm system, the fundamental concepts and some methodologies reviewed in this paper may also be applicable for the study of whole-body vibration exposure.
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Affiliation(s)
- Ren G Dong
- Engineering & Control Technology Branch, National Institute for Occupational Safety and Health, 1095 Willowdale Road, Morgantown, West Virginia 26505, USA
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Radwin RG, Marras WS, Lavender SA. Biomechanical aspects of work-related musculoskeletal disorders. THEORETICAL ISSUES IN ERGONOMICS SCIENCE 2001. [DOI: 10.1080/14639220110102044] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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