An examination of the vibration transmissibility of the hand-arm system in three orthogonal directions

Abstract

The objective of this study is to enhance the understanding of the vibration transmission in the hand-arm system in three orthogonal directions (X, Y, and Z). For the first time, the transmitted vibrations distributed on the entire hand-arm system exposed in the three orthogonal directions via a 3-D vibration test system were measured using a 3-D laser vibrometer. Seven adult male subjects participated in the experiment. This study confirms that the vibration transmissibility generally decreased with the increase in distance from the hand and it varied with the vibration direction. Specifically, to the upper arm and shoulder, only moderate vibration transmission was measured in the test frequency range (16 to 500 Hz), and virtually no transmission was measured in the frequency range higher than 50 Hz. The resonance vibration on the forearm was primarily in the range of 16–30 Hz with the peak amplitude of approximately 1.5 times of the input vibration amplitude. The major resonance on the dorsal surfaces of the hand and wrist occurred at around 30–40 Hz and, in the Y direction, with peak amplitude of more than 2.5 times of the input amplitude. At higher than 50 Hz, vibration transmission was effectively limited to the hand and fingers. A major finger resonance was observed at around 100 Hz in the X and Y directions and around 200 Hz in the Z direction. In the fingers, the resonance magnitude in the Z direction was generally the lowest, and the resonance magnitude in the Y direction was generally the highest with the resonance amplitude of 3 times the input vibration, which was similar to the transmissibility at the wrist and hand dorsum. The implications of the results are discussed. Relevance to industry Prolonged, intensive exposure to hand-transmitted vibration could result in hand-arm vibration syndrome. While the syndrome's precise mechanisms remain unclear, the characterization of the vibration transmissibility of the system in the three orthogonal dimensions performed in this study can help understand the syndrome and help develop improved frequency weightings for assessing the risk of the exposure for developing various components of the syndrome.

Vibrations transmitted from human hands to upper arm, shoulder, back, neck, and head

“…Other studies have also measured the vibration transmissibility at the wrist, elbow, forearm, and upper arm (Pyykko et al, 1976; Reynolds and Angevine, 1977; Aatola, 1989; Gurram et al, 1994; Adewusi et al, 2010; Thomas and Beauchamp, 1998; Xu et al, 2009, 2015; Welcome et al, 2015; Marchetti et al, 2015). The theoretical relationship between the transmissibility and the driving-point response functions have also been described (Dong et al, 2013b).…”

“…One of the major remaining resonances usually occurs in the range of 20–40 Hz. It can be clearly identified from the vibration transmissibility measured at the wrist, forearm, and elbow (Thomas and Beauchamp, 1998; Xu et al, 2009, 2015; Welcome et al, 2015; Marchetti et al, 2015). It can also be clearly observed in the impedance data, but the impedance resonant frequency is higher than the transmissibility or apparent mass resonant frequency; the impedance is equal to the apparent mass multiplied by the frequency.…”

Design and Testing of a 3-DOF Robot for Studying the Human Response to Vibration

“…Experimental studies have been conducted in controlled and reproducible conditions, in order to observe the mechanical behavior of the human body under WBV conditions and to develop mathematical models representing specific aspects of the body's response [9][10][11][12][13][14][15][16][17][18]. Tarabini et al [12] investigated the effect of body posture on the apparent mass distribution of standing subjects, applying the vibration with an electrodynamic shaker.…”

Hand-Arm Vibration Assessment and Changes in the Thermal Map of the Skin in Tennis Athletes during the Service

“…Welcome et al [14] say that the hand-arm vibration (HAV) exposure is directly associated to the hand-arm vibration syndrome (HAVS), which is a syndrome that affects the blood vessels, joints, muscles, and nerves of the hand, wrist, and arm. These authors have concluded that the vibration transfer depends on the vibration direction and the measurement location.…”