i want to design rock drill handle to avoid the Vibration White Finger(VWF).VWF generally occurs to the human hand in the frequency range of 25-50 Hz . The rock drill can be modeled as damped DVA with damped primary mass with base excitation . Here primary mass is handle mass plus apparent hand mass ,secondary mass is absorber mass.so i want to know the optimum values of stiffness and damping constants to minimize the transmissibility to primary mass in the frequency range 25-50 Hz.
Hi,
You will want the absorber to have the same natural frequency of the primary system (k1/m1 = k2/m2) in order to have the highest reduction of the primary system's resonance.
However, this will cause the 2 degree-of-freedom system's (primary+absorber) response to have two new resonance peaks at a higher and a lower frequencies than the original natural one. You will be able to handle the new peaks' magnitude by choosing the right damping c2. I would suggest you build a simple matlab model to have an idea of the parameters' influence on the system's response.
Best,
G.
Hi Vamsi KRISHNA Kaki, this may help you:
https://www.tcsme.org/Papers/Vol34/Vol34No1Paper8.pdf
Regards
Be careful, you are reasoning with 1 DoF mass-springs, your real life problem is 3-dimensional, and for example the rocking modes of your TVA could aggravate the problem ! You should consider using FEM and/or a professional consultant in this matter !!!!
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