N 



X 



>- 

 o 



z 



LU 



ID 



o 



LU 

 CC 

 LL 



_J 

 < 

 DC 



ID 



30 

 20 



10 



MODAL FREQUENCY 

 'CROSSOVER RANGE" 



CRITICAL TENSION 

 RANGE 



I ! 



ID 



o 



CD 



od 



II 



< 



LU 



I 

 t 



o 



CD 



o 



CO 



II 

 < 



LU 



O 



O 



jo 



o 



o 



100 



200 



500 



1000 



2000 



5000 



TENSION, H/NEWTONS 



Figure 3.9 The measured vibration frequencies of a Double-Armored Steel cable in water as a function of the tension. The 

 natural frequency "crossover" range for slack cables with small sag is predicted by the dashed lines for two values of the meas- 

 ured cable elastic modulus, EA. Legend for data points: •, O, Lowest symmetric mode of the slack DAS cable; □, Taut cable 

 natural frequency in the second (n = 2) mode; • — , experimental runs 10, 7, 23 from Table 3.2. 



74 



