used to return to the plot selection screen, redraw the current plot, or 

 return to the horizontal menu. The lower portion of the vertical menu is 

 provided so that the user can update the design variables and immediately see 

 the effect on the design diagrams. To update a variable, the user simply 

 moves the cursor to the variable and presses return. A program prompt will 

 appear at the bottom of the screen. After the new value is entered, the user 

 presses return, then moves the cursor to UPDATE GRAPH and again presses 

 return. The plot will be updated with the new value. 



8. Once the optimal design stress is computed in the fourth screen, 

 the user can return to the plot selection screen and select SUMMARY. The 

 fifth and final screen will then appear with the inputs and the associated 

 design stress, factor of safety, and dolos dimensions. The user has the 

 choice of writing the values on this screen to a file called CAUD.PRN, 

 returning to the plot selection screen, or exiting the program. 



Stress computation 



9. The four dolos design subroutines consist of a control module and 

 static, pulsating, and combined stress modules. The control module combines 

 the stress subroutines with the graphics routines. The stress routines are 

 all of the same nature, as follows. Each of the stress routines loads the 

 probability density or ordinate array and the corresponding stress or abscissa 

 array. The static nondimensional stress array is based on a modified log- 

 normal distribution with the mean and standard deviation adjusted 

 deterministically for waist ratio and the number of layers. The pulsating 

 nondimensional stress array is computed using a Rayleigh distribution with the 

 mean of the maximum stress computed using the average of the highest one -tenth 

 waves . Each of the static and pulsating stress routines integrates the 

 density function using a composite Simpson's rule. The step size for this 

 integration is 0.333 and the number of steps is 600. 



10. The combined stress routine is similar, except that the static and 

 pulsating density functions are first convolved to achieve a single density 

 function. This convolution is done using the composite Simpson's rule with a 

 step size of 0.333, a lag size of 0.333, and a total of 600 steps. The re- 

 sulting combined density function is then integrated to get a combined 

 exceedance probability function, again using the composite Simpson's rule with 

 600 steps of size 0.333. 



A4 



