HAVS and HAV-nots: Investigating Resonance in the Human Arm Caused by Contact with Machinery

Mechanical vibration is a vast field composed of thousands of studies and experiments regarding individual systems and structures’ vibrations and oscillations. In this paper a special and complex case regarding hand-arm vibration will be studied and analyzed mathematically. The human hand-arm system is affected by vibrations caused by contact with vibrating objects. In order to understand the effect on the hand-arm system, a mathematical model of the system as two viscoelastic rods connected by a hinge was derived. Using this model, it was possible to derive the propagation of both the longitudinal and bending vibrations of the arm, and find the resonance frequencies of the system from the elbow to the shoulder. The harmful effect of these frequencies is discussed with regards to Hand-Arm Vibration Syndrome, a disease stemming from repeated contact with vibrating objects. Hand-Arm Vibration Syndrome is found to be a pervasive issue among physical laborers who use vibrating machinery. A sample set of construction tools is analyzed and compared with the modeled resonance frequencies of the arm. Considering the resonance frequencies of the arm is significant for tools manufacturers. Research on the frequencies at which tools function may be overly dangerous to workers who are required to handle such tools frequently.