Question

Linked Answer Question:
A vibratory system consists of a mass 12.5 kg, a spring of stiffness 1000 N/m, and a dashpot with damping coefficient of 15 Ns/m

The value of logarithmic decrement is

• A. 1.35
• B. 0.422
• C. 0.68
• D. 0.66

Answer 1

The correct option is B 0.422

Damping ratio:

$\xi =\frac{c}{2\sqrt{km}}=\frac{15}{223.6}=0.0671$

Logarithmic decrement

$\delta =\frac{2\pi \xi }{\sqrt{1-{\xi }^2}}=\frac{2\pi \times 0.0671}{\sqrt{1-(0.0671{)}^2}}$

$=0.422$