Experimental Analysis for Vibration Transmission from Angle Grinder to Hand-Arm

Eng, Jia Jun (2020) Experimental Analysis for Vibration Transmission from Angle Grinder to Hand-Arm. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

For the workers in engineering or other fields, there are many cases of using the vibrating tools often in their daily life. Adjustable speed is normally installed on the hand tools to create different forces and effects on certain work. However, excessive vibration brings serious syndrome and even lead to diseases to human body which cannot be cure. Hand-arm Vibration Syndrome (HAVs) is commonly found on the worker who often use vibrating tools when working. It causes the changes in the sensation of the fingers which can results in permanent numbness of the fingers, muscle weakness as well as bouts of white fingers. For the experimental studies, two experiment were conducted to determine the transmissibility ratio for different operation on both genders using the same angle and the maximum safety time to operate the angle grinder in different operations comparing on both genders. Seven male and seven female operators were used for the experimental studies. With the help LMS Test Lab software, data was collected through different centre frequencies in 1/3 octave graph. From the experimental results, the vibration transmissibility ratio from handle bar of angle grinder to hand is higher in female than male operators while grinding operation provided highest transmissibility ratio following by holding the grinder and cutting operation. The sizes of the hand of female is smaller, having higher sensitivity on vibration transmission. For grinding operation, operators require higher force to hold the angle grinder, higher vibration is absorbed during the operation. Grinding operation experienced amplification region for male at 31.5Hz and 50Hz while 25Hz and 50Hz for male operators. For experiment of determining the maximum allowable safety time, female operators have higher total vibration magnitudes with the values of 2.7758m/s2, 2.837m/s2 and 2.738m/s2 on female operators obtained the values at on holding the grinder, grinding and cutting operations respectively. 2.6578m/s2, 2.7451m/s2 and 2.629m/s2 of total vibration magnitudes on male operators obtained the values at on holding the grinder, grinding and cutting operations respectively. This is subject to higher index of anthropometry measurements of male operators than female operators. For maximum allowable safety time, male operators have longer period of safety time compared to female in all operations as lower vibration magnitudes received from the angle grinder. For male operator, the maximum allowable safety time are 7.10 hours, 6.64 hours and 7.23 hours on holding the grinder, grinding and cutting operations. For female operator, it shows that 6.55hours, 6.21 hours and 6.67 hours are the maximum allowable safety time on holding the grinder, grinding and cutting operations. Since performing grinding operation has the highest value of vibration magnitudes on hand, less safety time can be used in the reference of A(8), 8-hour working day set by ISO5349.