This tutorial is the second of three basic tutorials created to illustrate commom features in ANSYS. The plane stress bracket tutorial builds upon techniques covered in the first tutorial (3D Bicycle Space Frame), it is therefore essential that you have completed that tutorial prior to beginning this one.
The 2D Plane Stress Bracket will introduce boolean operations, plane stress, and uniform pressure loading.
The problem to be modeled in this example is a simple bracket shown in the following figure. This bracket is to be built from a 20 mm thick steel plate. A figure of the plate is shown below.
This plate will be fixed at the two small holes on the left and have a load applied to the larger hole on the right.
The first step is to simplify the problem. Whenever you are trying out a new analysis type, you need something (ie analytical solution or experimental data) to compare the results to. This way you can be sure that you've gotten the correct analysis type, units, scale factors, etc.
The simplified version that will be used for this problem is that of a flat rectangular plate with a hole shown in the following figure:
Preprocessing: Defining the Problem
- Give the Simplified Version a TitleUtility Menu > File > Change Title
- Form Geometry
Boolean operations provide a means to create complicated solid models. These procedures make it easy to combine simple geometric entities to create more complex bodies. Subtraction will used to create this model, however, many other Boolean operations can be used in ANSYS.
- Create the main rectangular shape
Instead of creating the geometry using keypoints, we will create an area (using GUI)
Preprocessor > Modeling > Create > Areas > Rectangle > By 2 Corners
- Fill in the window as shown above. This will create a rectangle where the bottom left corner has the coordinates 0,0,0 and the top right corner has the coordinates 200,100,0.
(Alternatively, the command line code for the above command is BLC4,0,0,200,100)
- Create the circlePreprocessor > Modeling > Create > Areas > Circle > Solid Circle
- Fill in the window as shown above. This will create a circle where the center has the coordinates 100,50,0 (the center of the rectangle) and the radius of the circle is 20 mm.
(Alternatively, the command line code for the above command is CYL4,100,50,20 )
Now we want to subtract the circle from the rectangle. Prior to this operation, your image should resemble the following:
- To perform the Boolean operation, from the Preprocessor menu select:Modeling > Operate > Booleans > Subtract > Areas
- At this point a 'Subtract Areas' window will pop up and the ANSYS Input window will display the following message: [ASBA] Pick or enter base areas from which to subtract (as shown below)
- Therefore, select the base area (the rectangle) by clicking on it. Note: The selected area will turn pink once it is selected.
- The following window may appear because there are 2 areas at the location you clicked.
- Ensure that the entire rectangular area is selected (otherwise click 'Next') and then click 'OK'.