G. G. Parfitt 77 
RESPONSE RATIO, R (db) 
| 5 10 50 100 500 1000 
FREQUENCY (CPS) 
Fig. 4.9. Response ratio of the system of Fig. 4.8 with masses m added at the beam center. M = 50M;, 0;= 
0.01 [10]. 
quency of M on the spring mount on a rigid foundation has been chosen as 5 cps, 
and the beam damping factor 6; as 0.01. Response ratio is here taken as the 
ratio of amplitudes or forces at the beam center after and before the spring 
