2-D Static Truss

Problem Set 1

Resume the ANSYS Tutorial and make modifications to it as discussed below. To resume the ANSYS tutorial:

Start ANSYS; Specify the same directory but use a different jobname. Once ANSYS comes up, in the Utility Menu, click on:

Utility Menu > File > Resume from

Choose truss.db and click OK.

Consider the case where the displacement constrains at A and C are interchanged i.e.

• at A, only UX is set to zero

• at C, both UX and UY are set to zero

1. How would you expect the reaction forces at the supports A and C to change?

2. What can you say about how the x-component of the forces in the truss will change?

Re-solve the truss problem with the modified constraints. You can delete constraints using:

Main Menu > Preprocessor > Loads > Define Loads > Delete

It works similar to how you apply loads.

Tip: You can plot the displacement constraints in the Graphics window as follows:

Utility Menu > Pltctrls > Symbols

Select All Applied BCs for Boundary condition symbol. Click OK.

You might have to use :

Utility Menu > Plot > Replot

or

Utility Menu > Plot > Multi-plots

for the constraint symbols to appear in your plot.

Determine the following results from your ANSYS solution:

1. List the reactions. Note that you can save the reaction listing as follows: in the window that comes up with the listing of the reaction forces, click on:

File > Save As

2. List the element forces. From this determine the force in each member and whether the member is in tension or compression.

Go to Problem Set 2