Load by Equation
Altair EmployeeSummary:
If you want to know how to apply a load (force, pressure) using an equation (varying over a position), this is the article for you. A common request is "how can I apply a load like this one?"
Figure 1: Pressure on a ship panel.
Figure 2: Sinusoidal force.
Discussion:
- Defining of an equation
- Creating a local system
- Creating a load
The first thing we need to know is that the equation can be just a simple case, such as static pressure, or more complex, involving a combination of trigonometric functions and non-linear parameters. Considering this, the best practice is to define this equation using a more appropriate coordinate system (rectangular for the ship/wagon case and cylindrical for the trigonometric case).
For example, let's consider a case like this: We need to apply a force that is given by F0*sin(θ) in the upper quadrants working with OptiStruct.
Figure 3: Application example.
This is an applied force that is adjusted by a sine. It´s a wise choice to create a new coordinate system, define it as cylindrical and position it at the center of the circle (so we can control the coordinates to be used).
Figure 4: Cylindrical system definition.
Now, let´s create the load, in our example, a force. You can select the nodes, change the System Type to “Local”, choose the system created, select the Magnitude Type as “Equation” and type the equation.
Tip:
Figure 5: Load creation using a local system.
So, here we have our force created:
Figure 6: Forces.
If you would like to visualize the magnitude, you can check the “Display load handles” in View Control.
Figure 7: Forces and load handles.