Question

A single degree of freedom vibrating system has mass of 5 kg, stiffness of 500 N/m and damping coefficient of 100 N-s/m. To make the system critically damped

• A. Only the mass is to be increased by 1.2 times.
• B. Only the stiffness is to be reduced to half.
• C. Only the damping coefficient is to be doubled.
• D. No change in any of the system parameters is required.

Answer 1

The correct option is D No change in any of the system parameters is required.

$\text{Given}m=5\text{kg,}k=500\text{N/m},$

$c=100\text{N-s/m}$

For critical damping,

$c_c=2\sqrt{mk}=2\sqrt{5\times 500}$

$=2\times 50=100\text{N-s/m}$

$\therefore \text{As given damping coefficient is same as critical damping coefficient. So, no change in any of the system parameters is required.}$