Answer Happy

Between a solid mass of 10 kg and floor, two slab of
isolator, natural rubber and felt are kept in series as shown in
Figure Q1(b). The natural rubber slab has a stiffness of 3000 N/m
and an equivalent viscous damping coefficient of 110Ns/m. The felt
slab has a stiffness of 12,200 N/m and an equivalent viscous
damping coefficient of 170 Ns/m
(i) Sketch the single degree of freedom spring-mass-damper
system
(ii) Determine the undamped and damped natural frequencies
of the system in the vertical direction. Neglect the mass of the
isolator
m = 1 kg rubber felt Figure Q1(b)