2.000 



0.713 



1.000 



1.426 



0.500 



2.850 



0.250 



5.600 



0.100 



14.260 



0.050 



28.500 



0.030 



47.500 



0.010 



142.600 



0.005 



285.000 



As in the first example, cable lengths are chosen to give values of ^ coincident 

 with those used in the calculation of Figures 2 to 13, 15 to 22, and 25 to 32. These 

 lengths and the corresponding values of ^ and c/L are given in Table V. 



Table V. Cable Lengths Used in Design Example 

 for Steel Cable 



L(fO _M c/L 



15,700.0 



7, 850. 



3,925.0 



1,963.0 



785.0 



393.0 



236.0 



78.5 



39.3 



A similar table to that derived in the previous design example may now be 

 set up and the numerical computations performed as above. These calculations are 

 summarized In Table IV, and the relationship between the input amplitude of 

 oscillation, [Uq|, and the allowable circular frequency, to, of that amplitude is 

 illustrated in Figure 34. 



DISCUSSION OF RESULTS OF THE APPLICATION OF THE PROPOSED 

 DESIGN PROCEDURE 



Figures 33 and 34 show the results obtained in the application of the proposed 

 design procedure to the two hypothetical cases described above. 



In any load-lowering operation, the cable used will have a certain known 

 ultimate load at which the cable could be expected to break. With repeated use 

 of a particular cable, this ultimate load will decrease. Hence, for any lowering 

 operation a safety factor must be chosen defining a load, or corresponding stress, 

 which should not be exceeded. This allowable working stress Is assumed to include 

 static stress due to both the load and cable — the latter being negative In the case 

 of a buoyant cable such as polypropylene — and the dynamic stress. 



This discussion and the design procedure proposed earlier in the report are 

 based on the assumption that a particular maximum dynamic stress is given which 

 should not be exceeded during the lowering or raising operation. 



15 



