Vibration Dose Value Research Articles

Whole Body Vibration Exposure to Train Passenger

Problem statement: Train is one of the important and famous public transportations in the whole world. High magnitude of whole-body vibration formed by the train may cause diseases and health problems to the human especially a low back pain. This study will give an account of daily exposure to vibration A(8) and Vibration Dose Value (VDV) exposed to the passengers travelling in the train and the effects produced by the exposure towards human body. Approach: One national train travelled from East Coast to the South has been chosen to conduct the study. The whole-body vibration exposure was measured in 8 h, which is equal to the duration for normal occupation condition. All the data was computed by using IEPE (ICPTM) accelerometer sensor connected to DT9837 device which is capable to measure and analyze vibration effectively. The vibration results attained were displayed in personal computer by using custom Graphical User Interface (GUI). MATLAB software was used to interpret the data obtained. From the results shown, the whole-body vibration exposure level can be determined. Results: The values of daily exposure to vibration A(8) and Vibration Dose Value (VDV) in Experiment 3 were 0.3749 m sec-2 and 1.2513 m sec-1.75 respectively. Conclusion: It can be concluded that the whole-body vibration absorbed by human body enhanced when the duration of vibration exposure and the total of the trips that has been passed by the passengers increased. This can be proved by the increasing of the value of daily exposure to vibration A(8) and Vibration Dose Value (VDV) calculated in the study.

Whole-body vibration experienced by haulage truck operators in surface mining operations: A comparison of various analysis methods utilized in the prediction of health risks

Whole body vibration (WBV) was measured on eight surface haulage trucks in three size classes (35, 100, 150 ton haul capacities). Vibration was measured at the seat/operator interface in accordance with the ISO 2631-1 standard during 1 h of normal operation. Highest acceleration readings were observed in the z-axis (vertical). Estimated equivalent daily exposure values in the range of 0.44–0.82 ms −2 were observed using the frequency-weighted r.m.s method and 8.7–16.4 ms −1.75 using the vibration dose value method. Assessment was carried out using ISO 2631-1 and 2631-5. Operators of surface haulage trucks are regularly exposed to WBV levels that exceed safety limits as dictated by the ISO 2631-1 standard. However, according to ISO 2631-5 the probability of an adverse health effect remains low. These findings confirm an apparent disagreement between the two analysis methods.

A Longitudinal Study of Low Back Pain and Daily Vibration Exposure in Professional Drivers

The aim of this study was to investigate the relation between low back pain (LBP) outcomes and measures of daily exposure to whole-body vibration (WBV) in professional drivers. In a study population of 202 male drivers, who were not affected with LBP at the initial survey, LBP in terms of duration, intensity, and disability was investigated over a two-year follow-up period. Vibration measurements were made on representative samples of machines and vehicles. The following measures of daily WBV exposure were obtained: (i) 8-h energy-equivalent frequency-weighted acceleration (highest axis), A(8)(max) in ms(-2) r.m.s.; (ii) A(8)(sum) (root-sum-of-squares) in ms(-2) r.m.s.; (iii) Vibration Dose Value (highest axis), VDV(max) in ms(-1.75); (iv) VDV(sum) (root-sum-of-quads) in ms(-1.75). The cumulative incidence of LBP over the follow-up period was 38.6%. The incidence of high pain intensity and severe disability was 16.8 and 14.4%, respectively. After adjustment for several confounders, VDV(max) or VDV(sum) gave better predictions of LBP outcomes over time than A(8)(max) or A(8)(sum), respectively. Poor predictions were obtained with A(8)(max), which is the currently preferred measure of daily WBV exposure in European countries. In multivariate data analysis, physical work load was a significant predictor of LBP outcomes over the follow-up period. Perceived psychosocial work environment was not associated with LBP.

Whole body vibration exposures in metropolitan bus drivers: A comparison of three seats

Using a repeated measures study design, three different seats were evaluated as 12 metropolitan bus drivers drove a standardized test route including city streets, old and new freeways, and a street segment containing 10 large speed humps. Three comparisons were made: (1) comparing seats made by different manufactures (Seats 1 and 2), (2) comparing seats with a standard foam (Seat 2) and silicone foam (Seat 3) seat pans, and (3) comparing WBV exposures based on individual factors such as seat pressure settings and body weight. Whole body vibration (WBV) exposures were measured using a tri-axial seat pan accelerometer and the attenuation capabilities of each seat were evaluated by comparing the vibrations measured at the floor and seat of the bus. There were significant WBV exposure differences between the various street types, which was shown across all seat types. The city street and older freeway segments had the highest WBV exposures with both segments producing WBV exposures slightly above the action limit for vibration dose value (VDV). Relative to Seat 2, Seat 1 performed better at attenuating impulsive and shock related WBV exposures; however, neither seat performed significantly better when average vibration ( A w ) and VDV WBV exposures were compared. In addition, no performance differences were seen between the standard foam (Seat 2) and silicone foam (Seat 3) seat pans. Seat suspension stiffness (air pressure) was also examined, and the results indicated that the higher the seat air pressure the lower the A w , VDV, and static compressive dose ( S ed ) vibration exposures. This study provided a unique opportunity to evaluate on-the-job whole body vibration exposures in a standardized, controlled setting.

Evaluation of Vibration Assessment Criteria and Their Application to Stadium Serviceability

This paper explores the current recommended measures for assessing vibration serviceability in building structures and the recommendations for relating these vibration measures to levels of perception and expected occupant reactions. Two of these assessment measures, the maximum transient vibration value and vibration dose value, are discussed with respect to serviceability in stadium structures. The results of the monitoring and assessment of three stadium structures during several events are presented and these results indicate that the current recommendations are overly conservative in assessing occupant perception. Recommendations for vibration dose levels that are more consistent with the evaluation of events monitored in stadium structures are proposed.

Whole-body vibration exposure experienced by motorcycle riders – An evaluation according to ISO 2631-1 and ISO 2631-5 standards

Riders of twelve motorcycles, comprising 6 full-scale motorbikes and 6 motor-scooters, and 5 sedan vehicles, performed test runs on a 20.6 km paved road composed of 5 km, 5 km, and 10.6 km of rural, provincial and urban routes, respectively. Each test run of motorcycle was separately performed under speed limits of 55 km/h and 40 km/h. Tri-axial accelerations of whole-body vibration (WBV) were obtained by using a seat pad and a portable data logger, and the driver's view was videotaped with a portable media recorder. Root mean square ( RMS) acceleration, 8-h estimated vibration dose value ( VDV (8)) and 8-h estimated daily dose of static compression dose ( S ed ) were determined from the collected data in accordance with ISO 2631-1 and ISO 2631-5 standards. Experimental results indicate that the WBV values of the sedan vehicle drivers have low RMS, VDV (8) and S ed values ( RMS 0.27–0.32 m/s 2; VDV (8) 6.3–8.3 m/s 1.75; S ed 0.21–0.26 MPa). However, over 90% of the motorcycle riders had VDV (8) (mean 23.5 m/s 1.75) exceeding the upper boundary of health guidance caution zone (17 m/s 1.75) recommended by ISO 2631-1, or had S ed (mean 1.17 MPa) exceeding the value associated with a high probability of adverse health effects (0.8 MPa) recommended by ISO 2631-5. Over 50% of the motorcycle riders reached these boundary values for VDV and S e in less than 2 h. The WBV exposure levels of the full-scale motorbikes riders and motor-scooter riders were not significantly different. However, the RMS and VDV (8) values of motorcycle riders indicate significant roadway effect ( p < 0.001), while their S ed values indicate significant speed limit effect ( p < 0.05). This study concludes that the WBV exposure levels of common motorcycle riders are distinctively higher than those of sedans, even on a regular paved road. The impact on health of WBV exposure in motorcycle riders should be carefully addressed with reference to ISO 2631-1 and ISO 2631-5. Relevance to industry This study compares the predicted health risks of motorcycle riders according to ISO 2631-1 and ISO 2631-5 standards. Experimental data suggest that the vibration dose value of ISO 2631-1 and daily dose of equivalent static compression stress of ISO 2631-5 have roughly equivalent boundaries for probable health effects.

Cervical HIVD Related to Long-Term Whole Body Vibration and Awkward Posture

Background: The relationship between whole body vibration and awkward neck posture to cervical herniated intervertebral disc (HIVD) has been rarely reported. In this report, we present the case of an overhead crane operator, that had no known history of neck injury, but had long-term exposure to whole body vibration and improper neck posture, who developed cervical HIVD, which raises concerns over the possibility of occupational causation. Case: A patient, operating an overhead crane since Dec 26 th 1986, began to suffer from a neck pain and developed cervical HIVD in 1998. He had been frequently treated in an outpatient clinic, but the symptom was not improve. Eventually, he got HIVD surgery in Sep 6 th 2007, and then the symptom was relieved. There were 4 groups and 3 shift system in the patient’s overhead crane operation. He worked eight hours a day and 5 days a week. Actual crane work time was about 6 hours a day. The crane was located at 20 meters above the work field so that the crane operator had to look downward and the neck was bent by more than 20˚ for nearly the entire working day. Daily vibration exposure was expressed in terms of an 8-hour energy-equivalent frequency-weighted acceleration magnitude (A(8)) and vibration dose value (VDV). The daily A(8) was measured to be 0.23 ㎧² and the daily VDV was 7.4 ㎧ 1.75 . Although these levels were below the action level recommended by the International Organization for Standardization (ISO) and European Commission (EC), it cannot be ignored that whole body vibration in addition to an awkward neck posture may be related to an increased risk for neck disease. A long-term awkward posture can adversely impact the prevalence of neck disease. In addition, occupational exposure to whole body vibration along with an awkward neck posture seems to exacerbate these effects. Conclusion: An overhead crane operator may have acquired cervical HIVD due to an occupational causation. Therefore, to elucidate the causal relationship of an improper neck posture and whole body vibration to neck diseases, further investigations need to be conducted for lager sample of overhead crane operators that were exposed to a long-term awkward neck posture and whole body vibration.

Evaluation of Whole-Body Vibration and Ride Comfort in a Passenger Car

Whole-body vibration transmission influences comfort, performance, and long-term health of the driver. This current study is an objective evaluation of vehicle comfort characteristics based on standard mathematical formulae and frequency analyses. A variety of road types were selected and quantified by using the International Roughness Index (IRI). To assess vibrations transmitted to the passengers, vibration dose values (VDV), kurtosis, frequency response functions (FRF), and power spectral densities (PSD) of the compartment recorded signals were evaluated. SEAT values based on VDV outputs qualified the seat suspension as a vibration isolator, whereas the FRF and PSD quantified that behaviour through frequency analyses. Results indicate that energy concentration is at frequencies lower than 30 Hz. Such low frequency excitations are well attenuated by seat suspension in the vertical direction but are amplified (up to five times in harsh conditions) by a backrest in the fore-aft trend. Signals are amplified beyond 30 Hz, but amplitudes are still very low. It seems that backrest assembly still can be improved to become a better isolator. However, T15 (time to reach severe discomfort), even in harsh conditions, is more than three hours, which exhibits the overall good quality of the vehicle suspension systems. Kurtosis and VDV correlate with IRI and may be used as two objective metrics, together with jury evaluation, to create a vehicle vibration-comfort index in the future.

Earth Moving Machine Whole-body Vibration and the Contribution of Sub-1Hz Components to ISO 2631-1 Metrics

Exposure to whole-body vibration (WBV) is an occupational hazard for operators of industrial vehicles, such as earth-moving machines. Quantification of WBV exposure in terms of impact on health forms one aspect of the Standard ISO 2631-1 (1997). Regarding assessment of risk to health, ISO 2631-1 (1997) states that if WBV components below 1 Hz are not ;relevant nor important' then they can be excluded from the assessment. In this paper the influence of sub-1 Hz components in WBV acquired from a sample of 46 earth moving machines is evaluated in terms of their contribution to ISO 2631-1 WBV exposure dose metrics: frequency weighted r.m.s. and the vibration dose value (VDV). For the majority of machines, a high proportion of the horizontal (x- and y-axis) WBV r.m.s. and VDV values was generated by sub-1 Hz vibration components; there was a much lower proportion of the vertical (z-axis) vibration generated by such components.

Application of the “Contact Convoy” Concept to Hybrid Electric Vehicles

This paper applies an intelligent intervehicle device (termed a ldquobridging damperrdquo) to a convoy of in-contact vehicles. The field of application is backup for future automated highways and operation of novel guided systems using vehicle-following control. The vehicle represented in computer simulations is a parallel hybrid electric automobile. Using the advanced vehicle simulator (ADVISOR) model, the vehicle representation is tuned to achieve matching of the overall force and power characteristics and the same performance over an urban driving cycle. The model for which a dedicated Matlab Toolbox was constructed is described. Simulation results compare the vehicle-following control on its own with a passive damper and a ldquoquasi-activerdquo damper that is controlled in collaboration with the vehicle's drivetrain. Using transient disturbances in the form of wind gusts and short gradients, power peaks and longitudinal ride quality (vibration dose value) are used to evaluate the performance.

Virtual dummy with spine model for automotive vibrational comfort analysis

In this paper, the author presents a methodology for implementing a three-dimensional virtual dummy for human vibration investigations. The model is based on a multibody dynamics approach and includes a detailed spine submodel for accurate assessment of seated body vibration. The model has been used to compute vibrational modes and transmissibility functions. The response to vibrational inputs has been compared with previous experimental and numerical studies. The discussed model can be applied for the assessment of vibration dose value (VDV) and design optimisation of human-vehicle interface according to international standards.

Metrics of whole-body vibration and exposure–response relationship for low back pain in professional drivers: a prospective cohort study

The objective of this study was to investigate the relation between alternative measures of exposure to whole-body vibration (WBV) and low back pain (LBP) in professional drivers. The incidence of 12-month LBP, high pain intensity (numerical rating scale score > 5), and disability in the lower back (Roland and Morris disability scale score >or=12) was investigated in a cohort of 537 drivers over a 2-year follow-up period. LBP outcomes, individual characteristics, and work-related risk factors were investigated by direct interview using a structured questionnaire. Daily vibration exposure was expressed in terms of either equivalent acceleration over an 8-h reference period [A(8), root-mean-square (r.m.s.) method] or vibration dose value [VDV, root-mean-quad (r.m.q.) method]. From the vibration magnitudes measured on vehicles and total exposure duration, seven alternative measures of cumulative vibration exposure were calculated for each driver, using expressions of the form Sigma a (i)(m)t(i), where a (i) is the frequency-weighted r.m.s. or r.m.q. acceleration magnitude on vehicle i(a(ws) or a (wq), respectively), t(i) is the lifetime exposure duration for vehicle i, and m = 0, 1, 2, or 4. In the drivers' cohort, the cumulative incidence of LBP outcomes were 36.3% for 12-month LBP, 24.6% for high pain intensity, and 19.2% for disability in the lower back. A transition model, which takes into account the temporal sequence of cause and effect and captures the longitudinal part of the relationship, showed that VDV performed better than A(8) for the prediction of LBP outcomes. After adjusting for potential confounders, test for trends suggested an increased risk for developing high pain intensity and disability over time (and, to a lesser extent, 12-month LBP) with the increases of cumulative vibration doses computed from lifetime exposure duration and r.m.q. vibration magnitude (i.e. Sigma[a (wqi)(m)t(i)]). Measures of exposure duration, either daily or lifetime, also provided good indications of risk for LBP outcomes over time. Physical work load, but not psychosocial environment, was significantly associated with the occurrence of LBP outcomes over time. Measures of vibration exposure derived from exposure duration (daily or lifetime) and r.m.q. acceleration magnitude (VDV, Sigma[a(wqi)(m)t(i)]) were better predictors of LBP outcomes over time than measures of vibration exposure including r.m.s. acceleration (A(8), summation operator[a(wsi)(m)t(i)]). Patterns of exposure-response relationship were more evident for the outcomes high pain intensity or disability in the lower back than for the binary response 12-month LBP.

Shock and impact levels on North American locomotives

While whole body vibration (WBV) levels on North American locomotives are low, it has been suggested that isolated shocks and impacts in the overall vibration environment may pose greater health risks for crew members. In this paper, the shock and impacts measured on locomotives are evaluated through the vibration dose value (VDV) and spinal stress methods given in international standard ISO2631. More than 90 h of measurement data are used in this analysis. This analysis found that shock and impact present a low probability of adverse health effects. For this data, the health guidance provided in ISO2631 for the VDV is more stringent than the health guidance for the spinal stress. The effects of occupant motion and other data artifacts are also discussed.

Predictions of health risks associated with the operation of load-haul-dump mining vehicles: Part 1—Analysis of whole-body vibration exposure using ISO 2631-1 and ISO-2631-5 standards

Predicted health risks, associated with the operation of load-haul-dump (LHD) vehicles, based on ISO 2631-1 criteria are limited and have not yet been determined according to ISO 2631-5 criteria. Therefore, health risks predicted by ISO 2631-1 and 2631-5 criteria are reported and compared in this paper. Whole-body vibration (WBV) exposure was measured according to procedures established in ISO 2631-1. A tri-axial seat pad accelerometer was used to measure vibration exposure at the operator/seat interface. According to ISO 2631-1 criteria, calculated 8-h equivalent vibration dose values placed three of the seven LHD operators above the health guidance caution zone (HGCZ) boundaries and four LHD operators within the HGCZ. However, health risks predicted by the ISO 2631-5 criteria were always lower than the risks predicted by ISO 2631-1 criteria. Relevance to industry In 2004, ISO released a new standard for the evaluation of WBV, ISO-2631-5. The boundaries for probable health effects were established using the best guidance at the time; however, they have not been epidemiologically validated and very few studies have reported health risks based on ISO 2631-5 criteria. This study provides a comparison of predicted health risks based on ISO 2631-1 and ISO 2631-5 and provides data that could suggest the ISO 2631-5 boundaries for probable health effects may be set too high. Alternatively, the data presented in this paper suggests more dialogue is required to identify the appropriate application of ISO 2631-1 and 2631-5 given the different health risks predicted for a data set with high shock content.

Effects of frequency, magnitude, damping, and direction on the discomfort of vertical whole-body mechanical shocks

The discomfort of seated subjects exposed to a wide range of vertical mechanical shocks has been studied experimentally. Shocks were produced from responses of single degree-of-freedom models with 16 fundamental frequencies (0.5–16 Hz) and four damping ratios (0.05, 0.1, 0.2 and 0.4) to half-sine force inputs. Shocks with a damping ratio of 0.4 were presented with both polarities. Each type of shock was presented at five unweighted vibration dose values (0.35–2.89 m s −1.75). The magnitude estimates of 15 subjects to all 400 shocks showed that the rate of growth in discomfort (the exponent in Stevens’ power law) decreased with increasing shock frequency from 0.5 to 4 Hz. Equivalent comfort contours showed greatest sensitivity from 4 to 12.5 Hz. At lower magnitudes, variations in discomfort with frequency were similar to weighting W b in British Standard 6841. At higher magnitudes, low frequencies were judged relatively more uncomfortable than predicted by this weighting. There were small but statistically significant differences in discomfort associated with variations in damping ratios and shock direction. It is concluded that the frequency dependence of discomfort produced by vertical shocks depends on shock magnitude, but for shocks of low and moderate discomfort, the current evaluation methods are reasonable.

Vibration Exposure and Biodynamic Responses during Whole-Body Vibration Training

Excessive, chronic whole-body vibration (WBV) has a number of negative side effects on the human body, including disorders of the skeletal, digestive, reproductive, visual, and vestibular systems. Whole-body vibration training (WBVT) is intentional exposure to WBV to increase leg muscle strength, bone mineral density, health-related quality of life, and decrease back pain. The purpose of this study was to quantitatively evaluate vibration exposure and biodynamic responses during typical WBVT regimens. Healthy men and women (N = 16) were recruited to perform slow, unloaded squats during WBVT (30 Hz; 4 mm(p-p)), during which knee flexion angle (KA), mechanical impedance, head acceleration (Ha(rms)), and estimated vibration dose value (eVDV) were measured. WBVT was repeated using two forms of vibration: 1) vertical forces to both feet simultaneously (VV), and 2) upward forces to only one foot at a time (RV). Mechanical impedance varied inversely with KA during RV (effect size, eta(p)(2): 0.668, P < 0.01) and VV (eta(p)(2): 0.533, P < 0.05). Ha(rms) varied with KA (eta(p)(2): 0.686, P < 0.01) and is greater during VV than during RV at all KA (P < 0.01). The effect of KA on Ha(rms) is different for RV and VV (eta(p)(2): 0.567, P < 0.05). The eVDV associated with typical RV and VV training regimens (30 Hz, 4 mm(p-p), 10 min.d(-1)) exceeds the recommended daily vibration exposure as defined by ISO 2631-1 (P < 0.01). ISO standards indicate that 10 min.d(-1) WBVT is potentially harmful to the human body; the risk of adverse health effects may be lower during RV than VV and at half-squats rather than full-squats or upright stance. More research is needed to explore the long-term health hazards of WBVT.

Whole body vibration exposure in heavy earth moving machinery operators of metalliferrous mines

As mining operations get mechanized, the rate of profit generation increases and so do the rate of occupational hazards. This study deals with one such hazard - occupational vibration. The present study was carried out to determine the whole body vibration (WBV) exposure of the heavy earth moving machinery (HEMM) operators in two types of metalliferous mines in India, when they were engaged in the mining activity. Cross-comparison was done of the vibration dose value (VDV) for HEMM operators as well as each type of mine. The VDV for the shovel operator in bauxite mine was observed to be 13.53 +/- 5.63 m/s(7/4) with 25% of the readings higher than the prescribed limit whereas in iron ore mine VDV for dumper operator was 10.81 +/- 3.44 m/s(7/4) with 14.62% readings on the higher side. Cross-comparison of the VDV values for bauxite and iron ore mines revealed that it was 9.57 +/- 4.93 and 8.21 +/- 5.12 m/s(7/4) with 21.28 and 14.95% of the readings on the higher side respectively. The Student's t test level was found to be insignificant for both type of mines, indicating that the WBV exposure is not dependent on the type of mine but is dependent on the working condition and type of HEMM in operation.

Optimal seat and suspension design for a quarter car with driver model using genetic algorithms

This paper presents an optimization of a four-degrees-of-freedom quarter car seat and suspension system using genetic algorithms to determine a set of parameters to achieve the best performance of the driver. Since the health of the driver is as important as the stability of the car, the desired objective is proposed as the minimization of a multiobjective function formed by the combination of not only suspension deflection and tire deflection but also the head acceleration and crest factor (CF), which is not practiced as usual by the designers. The optimization results are compared through step and frequency responses of the seat and suspension system for the optimum and currently used suspension systems. Comparatively better results are obtained from the optimized system in terms of resonance peaks, CF, and vibration dose value. The concept and the ideas set forth in this work are directly applicable to both the car suspension and seat design in industry.

Cabin attendants’ exposure to vibration and shocks during landing

The Scandinavian Airlines System (SAS) has noted that cabin attendants have reported an increase in health problems associated with landing. The European Union reports cover health problems related to neck, shoulder, and lower-back injuries. Moreover, analysis of these reports shows that the problems are often associated with specific airplanes that have a longer tail behind the rear wheels and appear more often in attendants who sit in the back of planes rather then the front. Against this background, this study measures and describes the vibration during landing in specific airplanes to evaluate the health risk for the cabin attendants. Measurements were conducted on regular flights with passengers in the type of airplane, Boeing 737-800, which was related to the highest per cent of reported health problems. All measurements were performed the same day during three landings in one airplane with the same pilots and cabin attendants. The measurements were carried out simultaneously on the cabin crew seats in the back and front of the passenger cabin. Under the cabin crew's seat cushions, a triaxiell seat-accelerometer was placed to measure the vibration in three axes. The signals from the accelerometers were amplified by charge amplifiers and stored on tape. The stored data were analysed with a computer-based analyse system. For the cabin attendants, the dominant direction for the vibration load during landing is the up-and-down direction although some vibration also occurs in the other horizontal directions. The exposure to vibration is higher on the rear crew seat compared to the front seat. For instance, both the vibration dose value (VDV) and the frequency-weighted acceleration in the dominant direction are more then 50% higher on the rear seat. The frequency-weighted acceleration and the VDV measured at the crew seats are below the exposure limits as described by the European vibration directive. The evaluation of the cabin attendants’ exposure to multiple shocks during landing shows that the potential of an adverse health effect for the cabin attendants is low in the front of the airplane and increases to moderate in the rear. Although this is a limited study, it could be conclude that there could be a risk for cabin attendants due to the exposure of multiple shocks. Therefore, efforts should be spent to minimize their risk by developing a better seat cushion and back support to lessen the effects of shocks. In addition, attendants should be informed about the most suitable posture to take during landing.

수직방향 전신 충격진동의 불편함 평가를 위한 주파수가중곡선 개발

Shock vibrations are usually experienced in vehicles excited by impulsive input, such as bumps. The frequency weighting functions of the current standards in ISO 2631 and BS 6841 are to help objectively predict the amount of discomfort of stationary vibration. This experimental study was designed to develop frequency weighting shape for shock vibration having various fundamental frequencies from 0.5 to 16Hz. The specks were produced from the response of single. degree-of-freedom model to a half-sine force input. Fifteen subjects used the magnitude estimation method to judge the discomfort of vertical shock vibration generated on the rigid seat mounted on the simulator. The magnitudes of the shocks, expressed in terms of both peak-to-peak value and un-weighted vibration dose values (VDVs) , were correlated with magnitude estimates of the discomfort. The frequency weighting shapes from the correlation were developed and investigated having nonlinearity due to the magnitude of the shock.