Chuteeh
Mechanical
- Nov 2, 2015
- 1
For a project using rotating voice coils motor in order to balance a system I need to determine the damping coefficient of these voice coils in order to insert it in a ADAMS model and analyse its performances.
Starting with the oscillation data obtained during a physical test on a mock-up, I used the Matlab tool vibrationdata in order to find the damping ratio of these voices coils. To find this value the vibrationdata tool makes a FFT and then a "Half-Power Bandwidth Curve fit" method... At the end I got : damping_ration = 0.061, as well as the natural frequency (fn) 3.1Hz and the Q factor 5.8
As I was not sure about either to insert a damping coefficient or damping ratio value in my ADAMS model, I sent an email to MSC and they answered me "In Adams, bushing required the damping coefficient values, in the units as: - newton-sec/meter - newton-meter-sec/deg"
So, I have to calculate the damping_coefficient using the damping_ratio, natural frequency...
This is obtained using the expression : c = 2.mass.omega_n.damping_ratio with omega_n = 2.Pi.fn
I get a certain value but I am totally not sure about the use of the mass m in this expression as I want to get the damping coefficient of a rotating system... Can I directly replace this mass by the mass inertia coefficient around which the system rotate (I_yy for example from the Matrix) ? Or what else should I do ? I would like to specify a damping coefficient in Translation in my ADAMS model...
Starting with the oscillation data obtained during a physical test on a mock-up, I used the Matlab tool vibrationdata in order to find the damping ratio of these voices coils. To find this value the vibrationdata tool makes a FFT and then a "Half-Power Bandwidth Curve fit" method... At the end I got : damping_ration = 0.061, as well as the natural frequency (fn) 3.1Hz and the Q factor 5.8
As I was not sure about either to insert a damping coefficient or damping ratio value in my ADAMS model, I sent an email to MSC and they answered me "In Adams, bushing required the damping coefficient values, in the units as: - newton-sec/meter - newton-meter-sec/deg"
So, I have to calculate the damping_coefficient using the damping_ratio, natural frequency...
This is obtained using the expression : c = 2.mass.omega_n.damping_ratio with omega_n = 2.Pi.fn
I get a certain value but I am totally not sure about the use of the mass m in this expression as I want to get the damping coefficient of a rotating system... Can I directly replace this mass by the mass inertia coefficient around which the system rotate (I_yy for example from the Matrix) ? Or what else should I do ? I would like to specify a damping coefficient in Translation in my ADAMS model...