Studies on the Threshold Limit Value of Local Vibration of the Vibrating Agricultural Machinery. (II)

Transmissibility

Abstract

The authors have determined the threshold limit value of local vibration of the vibrating agricultural machinery, in the previous paper. As this result showed the limit value curves went down at lower frequency (below 40-50Hz). To prove the cause, we have investigated the actual absorption and transmission of vibration in the human arm by taping piezo-electric-type transducer to the skin (near the bone) of the arm of an operator. The results obtained are as follows:
1) Steady state transmissibilities have approximately. a linear relationship with input ampltude, This is related to the damping and resilience properities of the bone and surrounding flesh.
2) Natural frequencies were obtained by bode diagram. The values were about 50, 25, and 15Hz at hand, radius and elbow joint.
3) The combination of the hand, radius, and elbow joint tends to prevent extensive high-frequency vibration propagation into the torso.