If you have ever used a power tool, you may have experienced a tingling sensation in your hands or fingers. However, for workers who use power tools as part of the job, regularly and for longer periods, tingling can become more persistent as a symptom of a condition called hand-arm vibration syndrome. It can signal the onset of more severe symptoms of damage to nerves and blood vessels in the hands and arms. Those more advanced symptoms can include severe skin discoloration, numbness, and a weakened grip. Preventing hand-arm vibration syndrome by reducing exposure to vibration is key.
Abstract The dynamic characteristics of a beam with multiple breathing cracks are studied in this paper. A systematic approach has been adopted in the present investigation to develop theoretical expressions for evaluation of natural frequencies and mode shapes. A simple elastic simply supported beam with two breathing cracks is considered for the dynamic analysis. The stiffness of the cracked beam is found out by using influence coefficients. The influence coefficients are calculated by using castigiliano's theorem and strain energy release rate SERR. The equation of motion of the beam was derived by using Hamilton's principle. The stiffness and natural frequencies for the multiple cracked beam calculated using eigen value approach.
Please join StudyMode to read the full document. Undamped systems and systems having viscous damping and structural damping are included. The vibration of a system involves the alternating transfer of energy between its potential and kinetic forms.
Aiming at the abnormal vibration of driver seat of a passenger car in idle condition, vibration acceleration of engine, frame and seat rail was tested to identify vibration sources. Order tracking and spectrogram analysis indicated that the second order self-excitation of engine was the main cause. To solve the problem, semi-active controlled hydraulic engine mount with air spring of which characteristics could shift between a high dynamic stiffness and a low one was applied.