• Title/Summary/Keyword: Whole-body Vibration

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Ride Quality Investigation of Passenger Cars on Different Road Conditions

  • Park, Se Jin;Subramaniyam, Murali
    • Journal of the Ergonomics Society of Korea
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    • v.32 no.4
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    • pp.389-396
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    • 2013
  • Objective: The ride qualities of the six passenger cars were evaluated in 4 subjects on the highway and uneven road. The relation between vibration with driving velocity and driving posture were also investigated separately. Background: Ride comfort plays an important role in the vehicle design. Vibration is the one of the principal components associated with ride comfort. Method: The acceleration of the foot, hip and back were measured using B&K accelerometers in this study. The velocity of the passenger cars was maintained at a constant speed of 80km/h on the highway and 40km/h on the uneven road. For evaluating the effects of driving velocity and driving posture on vehicle's vibration level, separate experiments were performed on the highway with 5 different vehicle speeds and 5 different backrest angles, respectively. Results: The overall ride value of the luxury car showed the best result while the smaller car showed the worst value on the highway. On the uneven road the overall ride value level was increased 75~98%. All the vehicles had the SEAT value less than 1. Faster the velocity lowers the SEAT value. The ride quality in terms of vibration gets worst when the backrest angle increased. Conclusion: The smaller car had a first mode at the higher frequency and showed higher vibration level. SEAT value was mostly affected by the seat property not by vehicle. We ranked the luxury car seat had a best vibration reduction quality than others based on SEAT values. When the driving velocity increased, the overall ride values were increased proportionally and the SEAT values were somewhat decreased. Application: Evaluation of whole-body vibration in the passenger car.

Work Types and Work Postures of the Workers in an Automobile Industry (자동차 제조업 근로자들의 작업유형과 작업자세)

  • Kim, Soon-Lae
    • Korean Journal of Occupational Health Nursing
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    • v.7 no.2
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    • pp.130-135
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    • 1998
  • To investigate the working characteristics of the workers by place of duty, a study was carried out among 591 male workers aged 20-55 employed in an automobile industry in Korea. Workers participated to this study were divided into low back pain(LBP) and control group, according to the self-reports by written questionnaires. Work factors and complaint rates of low back pain were compared to the work places. The results were as follows ; 1) The complaint rates of low back pain were 49.2%(292 men) as a whole, 58.6%(34 men) in Production Control Department I, 50.2%(120 men) in Stamping Tool Department, 46.9%(138 men) in Bus Department. 2) Lifting and earring work of individual workers were directly associated with low back pain. Frequency of lifting and carring work is higher in the Final Body Section(Production Dept. I) and Body I Section(Bus Dept.). 3) LBP group were more frequently involved in working in awkward position(Quality Control Section of Stamping Tool Dept.), bending(Body I Section of Bus Dept.) and twisting posture(Sash Section and Body I Section of Bus Dept.). 4 )Workers exposed to vibration during working shows the higher complaint rate of low back pain.

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Development of the Railroad Geotechnical Information Management System Using Web GIS (웹 GIS 기반 철도 지반정보 관리프로그램의 개발)

  • 황선근;이성혁;김현기;김정무
    • Journal of the Korean Society for Railway
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    • v.7 no.1
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    • pp.20-25
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    • 2004
  • Railroad geotechnical information management system was developed by using Web GIS and DB in this study. The standardization of railroad geotechnical information is progressed by classifying three groups as like basic informations, vibration informations along railway lines and design drawings. The basic informations consisted of basic and dynamic properties of soils, geophysical exploration and seismic survey/exploration. And the specification for 'human exposure to whole-body vibration' was adopted to construct the vibration informations along railway lines. The informations as like drawings and photographs were saved by changing to graphic files in the standardization of design drawings. In the case of standardization of geographical information, the topographical maps(NGIS, 1:5000) were primarily used as digital maps. Another digital maps(KRRI, 1:5000) and their geographical DB based on NGI code system were added on this maps. The standardized informations were used to construct their database. And railroad information management system was developed using Entity-Relation(ER) model which had a good feasibility for expansion and transition to other system in designing stage of database. This system consisted of layer selection, search and analysis of geotechnical informations and Zeus DB was adopted for GIS operating and user interface. This system could be a good tool for saving, searching and analyzing the geotechnical and geophysical informations. These DB systems would offered the basic informations to plans, design and construction of railroad lines etc. in practical use.

Vibration and Ergonomic Exposures Associated With Musculoskeletal Disorders of the Shoulder and Neck

  • Charles, Luenda E.;Ma, Claudia C.;Burchfiel, Cecil M.;Dong, Renguang G.
    • Safety and Health at Work
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    • v.9 no.2
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    • pp.125-132
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    • 2018
  • Background: According to the US Bureau of Labor Statistics, musculoskeletal disorders (MSDs) accounted for 32% of all nonfatal injury and illness cases in 2014 among full-time workers. Our objective was to review and summarize the evidence linking occupational exposures to vibration and awkward posture with MSDs of the shoulder and neck. Methods: A literature search was conducted using the terms musculoskeletal disorders, vibration, and awkward posture. All types of observational epidemiologic studies, with the exception of case reports, published during 1998-2015 were included. Databases searched were MEDLINE (Ovid), Embase (Ovid), Scopus, Ergonomic Abstracts, NIOSHTIC-2, and Health and Safety Science Abstracts. Results: Occupational exposures to whole-body or hand-arm vibration were significantly associated with or resulted in MSDs of the shoulder and neck. Awkward postures while working were also associated with MSDs in these locations. These findings were consistent across study designs, populations, and countries. Conclusion: Occupational exposure to vibration and awkward posture are associated with shoulder and neck MSDs. Longitudinal studies are required to elucidate the mechanisms responsible for these associations, and intervention studies are warranted.

Studies on the Nutrition under Abnormal Environment(I) -Nutrition under Vibration- (이상환경하(異常環境下)의 영양문제(營養問題) 연구(硏究)(제1보) -진동하(振動下)의 영양문제(營養問題)-)

  • Yu, Jong-Yull
    • Journal of Nutrition and Health
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    • v.4 no.4
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    • pp.15-23
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    • 1971
  • On the assumption that the supplementation of certain nutrients or foods to the rice diet (low protein, low fat, and low vitamins) may decrease, to some extent, the degree of suffering from abnormal environments, such as vibration, noises, gases, dusts, smog etc. a series of experiments were started. As the first report the nutrition under vibration was studied in this experiment. Sixty (60) young growing male rats weighing about 65 grams were used, grouping to five (5) groups, twelve (12) rats each group. They were fed on the following five (5) experimental diets: rice diet (basal diet), rice diet+casein, rice diet+vitamins, rice $diet+{\alpha}-tocopherol$, and rice diet+ginseng powder (see the tables 1 and 2) for the period of 14 weeks experiment. During the experiment period the half number of the rats of each group were exposed to the three (3) hours vibration every day. The protective effect of each diet against the vibration may be summarized as follows. 1. The growth of rice diet group was impaired significantly under vibration, However, those of other groups (protein-supplemented, vitamin-supplemented, ${\alpha}-tocopherol-supplemented$ and ginseng-supplemented groups) were impaired much less compared with rice diet group. 2. The feed efficiency of the rice diet group was decreased significantly under vibration. It is estimated that the biological availability of nutrients was impaired under this environment. On the other hand, the feed efficiencies of protein supplemented, of vitamin supplemented, and of ginseng supplemented groups were not decreased under vibration, statistically. 3. There is tendency that the food spillages of vibration groups are higher than those of non-vibration groups. Especially it seems true in the case of rice diet group. The food spillage may be, to some extent, related with mental nervousness of animals. From the point that the food spillage of ginseng supplemented group is significantly lower than those of other groups it is thought ginseng acts some good role in protecting nervous system from suffering from vibration. 4. In all groups except protein supplemented group, liver fat of vibration group tends to be higher than that of non-vibration group. 5. It shows that, in general, the serum alkaline phosphatase activity of the vibration group is significantly higher than that of the non-vibration group. It seems that there may be, to some extent, corelation between the amount of liver fat and serum alkaline phosphatase activity. 6. There is tendency that, in rice diet group, the organs of vibration group are smaller than those of non-vibration group, especially lung is so. It is thought that this may be due to the poor growth of whole body size in vibration group.

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Effects of Strengthening Exercise using Vibrating Leg-press (진동 레그 프레스를 이용한 근력운동의 효과)

  • Hwang, S.H.;Cho, Y.G.;Sohn, R.H.;Kim, Y.H.;Kim, H.S.;Lim, D.H.
    • Journal of Biomedical Engineering Research
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    • v.30 no.3
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    • pp.221-225
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    • 2009
  • The purpose of this study was to investigate the biomechanical effects of an application of whole body vibration during strengthening exercise. Every participant performed four weeks exercise program using general leg-press versus vibrating leg-press. Participants did legpress exercise three sets of 25 repetitions with the load of 25 percent of 1RM during first week, three sets of 20 repetitions with 40 percent of 1RM during second week, three sets of 15 repetitions with 60 percents of 1RM during third week, and three sets of 15 repetitions with 80 percent of 1RM during last fourth week. The vibration(25Hz, 5mm) was applied only to the vibration exercise group. A three dimensional virtual lower extremity model for one of subject and virtual leg-press model were generated. The knee extensor muscle forces were analyzed using the virtual model and the knee joint torque(maximum extension torque) was measured using an isokinetic device. Calculated muscle forces were smaller in vibrating leg-press exercise than in general leg-press exercise. An increase of the maximum knee extension joint torque was 2.14 times larger approximately after the four week vibration leg-press exercise program was performed.

Effect of Whole Body Horizontal Vibration Exercise in Chronic Low Back Pain Patients: Vertical Versus Horizontal Vibration Exercise

  • Kim, Heejae;Kwon, Bum Sun;Park, Jin-Woo;Lee, Hojun;Nam, Kiyeun;Park, Taejune;Cho, Yongjin;Kim, Taeyeon
    • Annals of Rehabilitation Medicine
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    • v.42 no.6
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    • pp.804-813
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    • 2018
  • Objective To elucidate the effect of a 12-week horizontal vibration exercise (HVE) in chronic low back pain (CLBP) patients as compared to vertical vibration exercise (VVE). Methods Twenty-eight CLBP patients were randomly assigned to either the HVE or VVE group. All participants performed the exercise for 30 minutes each day, three times a week, for a total of 12 weeks. Altered pain and functional ability were evaluated using the visual analog scale (VAS) and Oswestry Disability Index (ODI), respectively. Changes in lumbar muscle strength, transverse abdominis (TrA) and multifidus muscle thicknesses, and standing balance were measured using an isokinetic dynamometer, ultrasonography, and balance parameters, respectively. These assessments were evaluated prior to treatment, 6 weeks and 12 weeks after the first treatment, and 4 weeks after the end of treatment (that is, 16 weeks after the first treatment). Results According to the repeated-measures analysis of variance, there were significant improvements with time on VAS, ODI, standing balance score, lumbar flexor, and extensor muscle strength (all p<0.001 in both groups) without any significant changes in TrA (p=0.153 in HVE, p=0.561 in VVE group) or multifidus (p=0.737 in HVE, p=0.380 in VVE group) muscle thickness. Further, there were no significant differences between groups according to time in any of the assessments. No adverse events were noticed during treatment in either group. Conclusion HVE is as effective as VVE in reducing pain, strengthening the lumbar muscle, and improving the balance and functional abilities of CLBP patients. Vibrational exercise increases muscle strength without inducing muscle hypertrophy.

Application of FRF-Based Substructuring to Optimization of Interior Noise in Vehicle (실차 소음 최적화를 위한 주파수 응답 함수 합성법의 적용)

  • Jung, Won-Tae;Kang, Yeon-June;Kim, Sang-Hoon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11b
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    • pp.140-143
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    • 2005
  • The hybrid CAE/CAT methods are widely applied to product development in various fields because this method can predict the response of the whole system when a part of the system is changed. Especially, the hybrid CAE/CAT method is very useful to predict tile vehicle NVH characteristics after changing some parts of the vehicle. Target parts can be established on the basis of test models and FE models of the prototype constructed in the planning stage of car development. In this study, the topic was focused on the proper test-based FBS application process to predict vehicle NVH characteristic. First, the test-based FBS method was apply to vehicle substructure and car-body. And then the test-based model was replaced with FE model to apply hybrid CAE/CAT method. The replaced FE model was modified through the optimization process. The interior noise in vehicle during the drive was predicted with Modified FE model, then the predicted results were verified by experimenting with actual modified model.

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A Study on the Development of Grating Frame for Drain Water on Road (배수용 그레이팅 프레임의 개선에 관한 연구)

  • Lee, Eun-Jong;Kim, Key-Sun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.8 no.4
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    • pp.713-720
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    • 2007
  • Grating is an installed structure on the road for drain. This paper proposes a new product which can prevent the accumulation of earth and sand through the improvement of Grating structure. There were usually harmful insects and bad smell because of accumulated garbage in the frame of previous product. The whole thing of the existing. This study is to separate grating from body. Also body structure consists of frame and box for collecting sewage. Thus, earth and sewage are prevented from accumulating in the drain main hole. The contents of this study is designed safely after structure analysis and vibration shape analysis about new products.

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Vibration Characteristics and Topology Optimization of a Double Damper Lock-Up Clutch in a Torque Converter System (토크컨버터 장착 이중댐퍼 체결클러치의 진동특성해석 및 위상최적화)

  • Kim, Kwang-Joong;Kim, Cheol
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.8
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    • pp.1129-1136
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    • 2010
  • Damper springs in a drive-line absorb the impulsive torque generated when a lock-up clutch is connected directly, instead of via a fluid coupling. Design optimization and finite element analysis were performed to improve the shock- and vibration-absorption capacity of the lock-up clutch. For this purpose, a multi-body dynamics model was developed by including the main parts of a vehicle, such as an engine with a clutch, a transmission, drive shafts and wheels, and a whole mass of a vehicle. The spring constants were selected so that resonance of a system could be avoided. Damper springs were optimized on the basis of the spring constants, impulsive torques, compressed angles, spring counts, fatigue constraints, etc. Topology optimization was performed for three plates with the damper springs. The compliance was set up as an objective function, and volume fraction was fixed below 0.3. A new shape for the plates was proposed on the basis of the topology result.