In ANSYS Workbench structural analysis, it is often necessary to calculate the stress resultant on specific cross sections, especially the bending moment of the section. This can be achieved using the Mechanical Surface Slice function.
In this article, we will demonstrate the specific operation method with an example.
As shown in the figure below, a rectangular solid with dimensions of 1m x 1m x 2m is used. The left end face is fixed, and the right end face is subjected to an axial force of 150N (in the X direction), a lateral force of 100N (in the Y direction), and a lateral force of 50N (in the Z direction).
The components of the Force are shown in the following figure.
Create a local coordinate system at a distance of 0.8m from the fixed left end, as shown below. Rename the coordinate system as “local system” and set the origin coordinates of the coordinate system to (0.8, 0.5, 0.5). Then use the Transform tool to rotate it 90 degrees around the Y-axis to form the local coordinate system position as shown in the figure below.
In the right-click menu of the local coordinate system “local system”, select Create Construction Surface, as shown below.
Create a Surface in the local coordinate system direction through the above menu, and rename it as “section_surface”. The location of this cross section is shown in the following figure.
The theoretical value of the internal forces at this cross section can be calculated by force equilibrium. Note that the axial distance from the cross section to the loaded surface on the right end is 1.2m. Therefore, the components of each internal force at this cross section (in the global coordinate system) are as follows:
Axial force (in the X direction) is -150N.
Lateral force (in the Y direction) is -100N.
Lateral force (in the Z direction) is -50N.
Bending moment around the Z-axis is 120Nm.
Bending moment around the Y-axis is 60Nm.
Next, calculate the internal forces of the cross section using the slice reaction force.
First, add two probes under the Solution branch in the Project Tree: Force Reaction and Moment Reaction, as shown below.
In the Details of the Force Reaction and Moment Reaction objects, set the Location Method to Surface and select the previously created section_surface. Taking Moment Reaction as an example, its Details settings are shown in the following figure:
In Analysis Settings, select Yes for Nodal Forces under Output Controls, as shown below.
Solve the structure, and then view the results of Force Reaction and Moment Reaction as shown below:
Note that the calculation of the moment is based on the local coordinate system. Here, the X-direction is equivalent to the Z-direction in the global coordinate system, and the resultant moment vector of the cross section is shown in the following figure.
The above calculation results are completely consistent with the theoretical solution.