• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.7 no.1
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• pp.87-98
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• 1997

In this study, subway train vibration has been measured to characterize the whole body vibration of Seoul subway lines for various human postures. Results show that the floor vibration level of the subway trains in the vertical direction is higher than that in other directions. At the standing human posture, vibration level of the head in the right-left direction are increased while that in the vertical direction is decreased. It is assumed that the different flexibility of the human body and the rolling motion of the subway trains are the main cause. At the sitting posture with back seat on, vibration level in the right and left direction at the human ischial tuberosities is lower than that in other directions. Results also show that there were little difference between back-seat on model and back-seat off model. Transmissibility analysis shows how the subway vibration affects the response of a human body.

• Journal of KSNVE
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• v.10 no.2
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• pp.247-253
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• 2000

The evaluation of the ride quality had been performed by the subjective method before ISO2631(International Organization for Stadard 2631) and BS6841(British Standard 6841) was precented, but many research programs have been performed by the objective method after that. On this study, the ride quality was evaluated related with the objective method which considered the vibration which the human body feels on the driver's seat while driving on the road. In particular, we made the shock absorber nonlinear model and also selected the suitable shock absorber in the part of the vibration which the human body feels into the simulation. The shock absorber of suspension was dealt with 3 cases respectively with the front wheel and rear wheel. The vibration of the car driving on the road can be transferred to the wheel, the suspension, the vehicle body, the seat and the human body. The signal which was gained from the seat(hip) and the floor(foot) of the human body was changed to the vibration signal which the human body felt through using the frequency weighting function. And then the performance of the shock absorber was calculated through the statistic processing.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.522-528
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• 2000

Dynamic characteristics of seated human body were investigated by measuring apparent masses of eight different seating subjects exposed to vertical vibration. Two types of vibration signals - one is random signals over 1 to 30Hz having flat spectral density and the other is signals measured on seat rail in passenger car under driving conditions - were employed. It was found that the apparent masses are highly dependent on vibration level rather than type of the vibration signals. Based on the apparent mass measurements, a mathematical model of the human body in seating posture was developed by using genetic algorithm. Three-degree-of-freedom model was satisfactory in describing apparent mass of seated human body.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.656-660
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• 2009

Various dynamic models of seated posture human body have been developed because the importance about the ride comfort assessment of vehicles is highly emphasized from day to day. The dynamic models of human body make possible the simulation of ride comfort assessment by applied to the vehicle dynamic model. Recently, the importance of ride comfort is also regarded to working vehicles such as excavators and the research of the ride comfort assessment for working vehicle is required. Only vertical vibration dominantly occurs on the seat of the private car driving with constant velocity. In contrast, vertical/fore-and-aft/pitch vibration seriously occurs on the seat of the working excavator. So, the dynamic models of seated human body applied to working vehicles should describe the dynamic characteristics for vertical/fore-and-aft/pitch direction. In this paper, the dynamic characteristics of seated human body are represented as apparent inertia matrix. The apparent inertia matrix is obtained by the vertical/fore-and-aft/pitch excitation of seated human body. 6 resonance frequencies are observed in apparent inertia matrix. This result can be applied to develop the dynamic model for seated posture human body.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.4
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• pp.93-99
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• 2002

Ride comfort, one of the most important performances of a car, is affected by vibration, noise, dynamic movement, and ergonomic factors. Among these factors, ride comfort vibration is heavily affected by the seat system, tire, suspension, and body structure. In this study, vibration characteristics of seat, tire, suspension, and body structure are analyzed. The vibration transfer function from the road input to the human body is also investigated.

• The Transactions of the Korea Information Processing Society
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• v.7 no.10
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• pp.3119-3127
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• 2000

This paper is a study to find a new method of feature selection for vibrationof buman body by analyzing correlationof vibration between King Songdok Bell and Human body. The vibration characteristics are analyzed by matching body, vocal tract, diaphragm and asymmetrical clements of human body with Bell, resonator, hole in the ground and asymmetical elements. In the result, the characteristics of sound vibrationof King Songdok Bell is useful to apply it to vibration characteristics of human body because the vibration characteristics of ech elements is alike.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1990.10a
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• pp.91-98
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• 1990

This paper reviews the previous researches related to the effects of whole-body vibration on human performance. The physiological effects of vibration were reviewed in the first part, and the effects of vibration on vision and manual control performance were discussed. the relationships between vibration and ride quality were also discussed. ISO-2631 was briefly reviewed, and cautions and limitations were discussed to avoid misinterpretations when we accomodate Korean population to this standard. Further researches were recommended to get better understanding of response characteristics of Korean to whole-body vibration.

• Journal of the Ergonomics Society of Korea
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• v.22 no.1
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• pp.1-15
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• 2003

The resonance behaviour needs be understood to identify the mechanisms responsible for the dynamic characteristics of human body, to allow for the non-linearity when predicting the influence of seating dynamics, and to predict the adverse effects caused by various magnitudes of vibration. However, there are currently no known studies on the effect of vibration magnitude on the transmissibility to thoracic or lumbar spine of the seated person, despite low back pain(LBP) being the most common ailment associated with whole-body vibration. The objective of this paper is to develop a proper mathematical human model for LBP and musculoskeletal injury of the crew in a maritime vehicle. In this study, 7 degree-of-freedom including 2 non-rigid mass representing wobbling visceral and intestine mass, is proposed. Also, when compared with previously published experimental results, the model response was found to be well-matching. When exposed to various of vertical vibration, the human model shows appreciable non-linearity in its biodynamic responses. The relationships of resonance for LBP and musculoskeletal injury during whole-body vibration are also explained.

• Journal of the Ergonomics Society of Korea
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• v.32 no.4
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• pp.309-319
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• 2013

Objective: The aim of this study is to review and summarize human vibration measurement process, and necessity and methods of frequency weightings for human vibration. Background: Prolonged human exposure to hand-arm vibration and whole-body vibration can result in a range of adverse conditions and the development of occupational diseases such as vibration white finger. For preventing these adverse effects, it is important to correctly apply human vibration measurement process. Method: This manuscript was based on the review and summary of mechanical and human vibration relevant texts, academic papers, materials obtained through web surfing. Results: This manuscript summarizes human vibration measurement process described in ISO standards and relevant texts. The sensitivity of the human body to mechanical vibration is known to be dependent on both the frequency and direction of vibration. To take this into account, varying frequency weighting functions have been developed, and RMS frequency-weighted accelerations are used as the most important quantity to evaluate the effects of vibration on health. ISO provided nine frequency weighting functions in the form of curves and tables. Researches on frequency weightings are focused on development and validation of new frequency weightings to truly reflect the relationship between vibration exposure and its adverse effects. Application: This would be useful information for systematically applying human vibration measurement and analysis process, and for selecting appropriate frequency weighting functions.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.516-517
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• 2013

Whole body vibration is very important for operators in construction equipment (CE) industry. There is ISO 2631 regulation to protect operators of CE. Recently WBV is one of critical performance parameters of CE to give operators much better comfortable working environment. And there are many kinds of numerically simplified human body model for the motor industry. We applied one human body model in ISO 5982 for the CE development at early stage. And we've checked the validity of this model to consider WBV by the operator comfort point of view.