430 BELL SYSTEM TECHNICAL JOURNAL 



Then 



2 (280)' X 10 -_,„ ,, ,. 



k', = C02W2 = ^ -— = 2030 Ibs./in. 



386 



V 



2M2 _ < rr 



2h 



dm = -p:^ = -I I in. 



Hence the spring rate of the cushioning should be reduced from 3300 lbs. /in. 

 to 2030 Ibs./in. and the available space should be increased to accomodatg 

 the 0.77 inch maximum displacement before bottoming. 



3.4 Special Treatment of Strong, Low Frequency Elements 

 The product of the amplification factor (.4,„) and the maximum accelera- 

 tion {Gm) must be equal to or less than the maximum allowable slowly 

 applied acceleration (Gs): 



Ge = AmGm ^ G, . (3.4.1) 



For frequency ratios 



-^<i (3.4.2) 



C02 ^ 



Figure 3.2.2 shows that, approximately, 



Am = 2^ (3.4.3) 



C02 



for Si ^ 0.10. When this is so, we may combine (3.4.1) and (3.4.3) to 

 obtain the criterion 



2^G„, ^a. (3.4.4) 



C02 



Now, 



^^- = 1/1 = - 4/7- ''■'■'' 



Hence the criterion (3.4.4) may be written as 



2C.1 a/- ^ a (3.4.6) 



or 



Vh 

 where // is in inches and fi is in cycles per second 



A ? ^' (3.4.7) 



