Interactive Roark’s Formulas: Five Problems and Solutions 

Let's load a case from the Interactive Roark's Formulas application and solve a problem. Along the way, you will learn about many of the software's features. 



Problem 4  
Let's switch from beams to plates and learn more about how Interactive Roark's Formulas on TK Solver
works. The next problem involves a flat annular plate with uniform annular line load, fixed on the outside and free in the center. Using the Applications Menu in TK Solver, select Interactive Roark's Formulas on TK Solver and load Table 11.2, Case 1e. 



Enter the following inputs into the Variable Sheet:  


Solve. The Variable Sheet will appear as shown: 



Open the Plot Sheet and view the graphical output by highlighting each of the plot names and pressing F7. You may want to close the plots after viewing them to avoid cluttering the screen.  


The main design concerns appear to be at the center of the plate. This is where the deflection and tangential stress are maximized. In fact, there may be too much deflection. You can investigate how changes in the plate thickness will affect the deflection in the center. Specifically, you might like to generate a plot of the center deflection (yb) versus the plate thickness (t) as t goes from .25 to 1 in steps of .05.  
Use the List Solving Wizard in TK Solver for this. Start the wizard by picking it from the Wizards menu in the Menu bar. Follow the instructions in the opening screen, then click Next.  
The next screen prompts you for independent (input) and dependent variables. We are plotting the relationship of t, which is the input variable, and yb. Type t in the input variable field and select yb from the list of output variables, as shown below.  


Click Next. The next screen brings up the List Fill dialog box shown below. Enter the values shown to create a list for t.  


Click Next. With the next screen, shown below, TK Solver asks whether you want to build a plot andor a table, which displays the two lists in tabular form. Let's do both. Click the check boxes, and name the table and the plot ybcheck, as shown.  


Click Next. TK Solver repeatedly solves the equations for each of the t values and stores the resulting yb values in a list. The resulting plot and table are shown below.  




As you have seen, list solving can be used to study the relationships between any of the variables in a model
and the results can be displayed in plots or tables. This capability is in addition to the default plots that are automatically generated by the software. Before proceeding to the next problem, close all the sheets except the Variable Sheet. 