Ansys Motor-CAD: Mechanical Rotor Stress and Displacement

Hello everyone, David Giglio here with Ozen Engineering. In this video, I will show you how to use ANSYS Motor-CAD to perform rotor stress tests and deformation tests. Let's begin by opening the ANSYS Motor-CAD installation folder, then navigating to the Testorius folder.

Select BPM design traction and open the mechanical project. This model will appear, it's an IPM motor, and we have here these different parameters for the geometry templates, for the stator and the rotor.

Notice that in the rotor, we have this parameter called rotor lamination corner radius and we also have magnet corner radius. In practice, typically the rotor lamination openings do not have sharp corners, they are rounded.

Similarly, with the magnet corners, they are rounded, they don't have sharp corners. This is important to acknowledge and apply the proper radius for these corners. Otherwise, the stress results will be higher than what they are supposed to be. To adjust this, go to Input Data and select Geometry.

Then, select Corner Rounding Magnets, Single Definition for All and Corner Rounding Rotor Lamination, Single Definition for All. These parameters will appear in the geometry template. Next, we need to check Input Data, Materials.

We've reviewed the materials that we're using, and we can see the material database, the material used in this model. For example, we have Aluminum Alloy 195 cast. We see the mechanical properties, such as Poisson's ratio, Young's coefficient, and yield stress.

Similarly, for the other materials, we can see these mechanical properties in the Materials tab under Input Data. We can also see the mechanical properties, Young's coefficient, Poisson's ratio, yield stress, density, and weight.

In the Calculation tab, we select the Rotor Stress tab, not the E and VH and Forces tab. This tab is used to calculate noise, vibration, and harshness due to electromagnetic forces on the stator. In this example, we're focusing on the rotor stresses.

This motor is rated to operate at 15,000 rpm, and for the rotor stress deformation test endurance test, we typically run the motor over speed, 20% over the rating speed, so 18,000 rpm. We have an option here for Not Include Magnets or to Include Magnets. Let's do a quick test.

When we do not include the magnets, we see the stress (displacement) here. We look at the left side here, shading, and we could choose Mechanical Stress and Displacement. For now, we're looking at displacement, and we see the value here is 27.174 to the negative 3 micrometer.

This is basically a micrometer. 27.174 micrometers is the max. We can see here the values for the post area, post area here, and in the bridge as well. Notice this value, 27.174, is in micrometers. Now, we're going to go back to Calculation.

We're going to include the magnets, solve it again, and we're going to see that the max value basically doubled. The reason is that when the magnets are included, these magnets experience centrifugal forces, which transmit force and apply stress to the rotor material.

Where the magnets make contact with the rotor lamination, they will apply force, transmit this force, and basically, a stress results on the rotor material. The magnet will transmit force to the rotor material, and basically, a stress results on the rotor material.

That's why we see a higher displacement. Similarly, we could see the mechanical stress here, the maximum value, for 74 mega Pascals. We could see the distribution of the stress by the way, this is Von Mises stress, mega Pascals.

We could see the distribution of this Von Mises stress, and notice, it's a maximum of 474 mega Pascals. Now, let's go back to Not Include Magnets, run it again. We're going to see now this value is going to be practically almost half.

And we can see here, with all do not include magnets, but either way, so I'll put the data in tabular output results in tabular form. We see the rotor lamination stress average, we can see the yield stress value, 445, and we can see the ratio of the rotor lamination yield stress ratio.

This value and we see the safety factor. So we have all these results here. Again, we could include the magnets and see the result, run it again. It's real quick. This onboard stress, all gets results very fast, as you see. So again, we can look at the output data.

We can see the rotor lamination and stress average, we can see the yield stress value for 45 materials, we can see the yield stress ratio, and the safety factors, and there's other results here that you could analyze. And that is all for this video.

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