Transmission of vibration through glove materials: effects of contact force

Abstract

This study investigated effects of applied force on the apparent mass of the hand, the dynamic stiffness of glove materials and the transmission of vibration through gloves to the hand. For 10 subjects, 3 glove materials and 3 contact forces, apparent masses and glove transmissibilities were measured at the palm and at a finger at frequencies in the range 5-300 Hz. The dynamic stiffnesses of the materials were also measured. With increasing force, the dynamic stiffnesses of the materials increased, the apparent mass at the palm increased at frequencies greater than the resonance and the apparent mass at the finger increased at low frequencies. The effects of force on transmissibilities therefore differed between materials and depended on vibration frequency, but changes in apparent mass and dynamic stiffness had predictable effects on material transmissibility. Depending on the glove material, the transmission of vibration through a glove can be increased or decreased when increasing the applied force. Practitioner summary: Increasing the contact force (i.e. push force or grip force) can increase or decrease the transmission of vibration through a glove. The vibration transmissibilities of gloves should be assessed with a range of contact forces to understand their likely influence on the exposure of the hand and fingers to vibration.

Development of a finger adapter method for testing and evaluating vibration-reducing gloves and materials

“…7–9 is primarily associated with the resonance of the hand, which depends primarily on the apparent or effective mass and contact stiffness of the hand. Theoretically, these two factors have opposite effects on the resonant frequency and transmissibility [15,32]. Because both the glove material and the hand contact tissues exhibit large non-linear behaviors [32,33], the increased grip force can increase the stiffness of the glove material and that of the hand coupling.…”

“…Theoretically, these two factors have opposite effects on the resonant frequency and transmissibility [15,32]. Because both the glove material and the hand contact tissues exhibit large non-linear behaviors [32,33], the increased grip force can increase the stiffness of the glove material and that of the hand coupling. Although increasing grip force can also increase the hand effective mass, the percent change of the hand mass is usually much less than that of the contact stiffness in the gripping of a cylindrical handle, as identified from previous modeling studies [30].…”

Vibration Transmitted to the Hand by Backpack Blowers

“…Furthermore, the structure of the handle vibrated differently with a different grip force. The different grip force and contact area can also affect the biodynamic response of the hand [13,17].…”

“…The mechanical impedance of the hand depends on many factors such as contact area [10][11][12][13][14], contact force [12,[15][16][17][18][19], the posture of the hand [15,18,19], the direction of vibration [15], and frequency of vibration [11,14]. The changes in these factors will consequently affect the vibration transmitted to the hand.…”

“…The mechanical impedance of the hand at frequencies greater than 500 Hz increases with increasing magnitude of vibration [20], but another study has found that it is negligible at frequencies greater than 100 Hz [16]. The anti-vibration glove was designed to be able to attenuate vibration to the hand [21] but some studies have found that the performance can be different depending on the contact area [13], contact force [17], location of vibration [22,23], and frequency of vibration [23].…”