Author(s): Sebastian Vecchi, ANSYS Inc.
Problem Specification
1. Pre-Analysis & Start-Up
2. Geometry
3. Mesh
4. Physics Setup
5. Results
6. Verification & Validation
Physics Set-Up
Add Structural Conditions
Once having entered the Physics task of the workflow, the wall support needs to be defined. This is done by selecting Add next to Structural Conditions. In the Add drop down menu, there is an option for Support. Click this to open the Support selection menu. Select the face which is going to be attached to the wall, then press the blue ‘+’ button next to Location. Next, open the drop down menu below Type and choose User specified. Next, under Degrees of Freedom, set Translation X and Translation Y to be Free while Translation Z is set to Fixed. This allows the bar to expand in the X and Y directions while constraining Z.
The other end of the bar needs a displacement constraint in order to keep it from “clipping” into the other wall. Return to the Physics task, select Add to the right of Structural Conditions, and choose Displacement. Select the appropriate face, press “+” next to Location, and input 0.002 m in the Translation Z box. Then, type Free into the Translation X and Translation Y boxes. Using Free in these places will prevent the free end from being over constrained and calculate a more accurate stress distribution.
Next to Structural Conditions, press Add > Support, then select one of the cut sides as the Location and set the Type to User specified. Edit the Translation drop down menus until there is only one arrow going into our model. This creates a symmetrical constraint support for the shaft which allows it to deform while also not moving its location. Repeat this step for the other cut face.
Add Solid Thermal Conditions
Next, the temperature change needs to be added by selecting entire bar body, adding a Solid Thermal Condition > Temperature, and setting it to 122 degrees Celsius. Be sure to change to the Body selection mode using the toolbar at the top center of the model window. We know that it needs to be set to 122 degrees Celsius because there needs to be a 100 degree increase. The original temperature can be found by going back to the Physics section via the workflow, and then selecting Material Assignments. In this menu, the Zero-thermal-strain reference temperature can be found and used as the starting temperature for the material. The material was automatically assigned to be structural steel, but if a different material was used, the zero-thermal-strain reference temperature would be different and so would the thermal condition for the free end of the bar.