Frequency Weightings Based on Biodynamics of Fingers-Hand-Arm System

Abstract

The frequency weighting for assessing hand-transmitted vibration exposure is critical to obtaining a true dose-response relationship. Any valid weighting must have a solid theoretical foundation. The objectives of this study are to examine the biodynamic foundation for assessing the vibration exposure and to develop a set of biodynamic methods to formulate the frequency weightings for different anatomical locations of the fingers-hand-arm system. The vibration transmissibility measured on the fingers, hand, wrist, elbow, shoulder, and head was used to define the transmitted acceleration-based (TAB) frequency weighting. The apparent masses measured at the fingers and the palm of the hand were used to construct the biodynamic force-based (BFB) weightings. These weightings were compared with the ISO weighting specified in ISO 5349-1 (2001). The results of this study suggest that the frequency weightings for the vibration-induced problems at different anatomical locations of the hand-arm system can be basically divided into three groups: (a) the weighting for the fingers and hand, (b) the weighting for the wrist, elbow, and shoulder, and (c) the weighting for the head. The ISO weighting is highly correlated with the weighting for the second group but not with the first and third groups. The TAB and BFB finger weightings are quite different at frequencies lower than 100 Hz, but they show similar trends at higher frequencies. Both TAB and BFB finger weightings at frequencies higher than 20 Hz are greater than the ISO weighting.

Recent Advances in Biodynamics of Human Hand-Arm System

“…Hence, the inertial force due to the transmitted acceleration on the fingers should be directly correlated to the interface dynamic force. This hypothesis was supported from the study by Dong et al 55) . They also found that at lower frequencies, the transmissibility on the fingers was not correlated to the interface biodynamic force.…”

“…7. Dong et al 55) reported that the accelerations on the arm calculated using the TAB weightings were highly correlated to those calculated using the ISO weighting 7) . Another study 56) reported that the wrist sensorineural disorders were reasonably correlated to the ISO-weighted acceleration.…”

“…Hence, it has a relationship to the biodynamic stresses and strains. Several investigators proposed using the transmissibility at an anatomical location as a frequency weighting for assessing the risk of the vibration-induced disorders at that location 27,54,55) . Several examples of the transmitted acceleration-based (TAB) weightings are shown in Fig.…”

Relationships of neurosensory disorders and reduced work ability to alternative frequency weightings of hand-transmitted vibration

“…Acceleration magnitudes were weighted using the frequency weightings displayed in figure 1 (11): W h is the frequency weighting specified in ISO 5349-1 (2); W h-bl is the band-limiting component of W h (10); W hf is a frequency weighting based on biodynamic studies of finger vibration power absorption (12); and W hT is a frequency weighting based on a Japanese study of VWF prevalence in worker groups investigated from 1957-1977 (13 The results of tool rms acceleration measurements with the four alternative frequency weightings are reported in a previous study (5).…”

Vascular Responses to Vibration Are Frequency Dependent

“…However, recent experimental and epidemiological studies suggest that this weighting may underestimate the risk of injury associated with exposure to higher frequency vibration (1,2). The goal of this study was to use a rat-tail model to determine how exposure to higher frequency vibration (i.e., 62.5 -250 Hz) affects peripheral nerves and arteries.…”