Using Mechanica Lite to analyze stress in a rotating shaft
Using Mechanica Lite to analyze stress in a rotating shaft
(OP)
I'm having trouble running a Mechanica test on a shaft. The version of Pro/E I have only has Mechanica Lite. Here's a picture of the shaft. It's supported at the bearings shown and the rotor in the middle rotates. I want to study the stress in the shaft under the weight of itself and the rotor and under torsion from the rotor spinning.
http://i.imgur.com/iX2IK.jpg
I've opened Mechanica Lite from the shaft part file, but was unable to constrain properly where the bearings would be or apply the moment properly. The best thing I could think of was to add blocks as shown below that would act to support the shaft and that would essentially serve as the bearings. In the testing. I was able to constrain these blocks.
http://i.imgur.com/ci25b.jpg
Now I'm trying to apply a moment, but the moment option is greyed out no matter what I select (shown below). I'm also unsure how to apply gravity. I would appreciate help in running this analysis. My end goal is to see how much I can hollow out the shaft to save on weight and maintain strength. Thanks.
http://i.imgur.com/j13P7.jpg
http://i.imgur.com/iX2IK.jpg
I've opened Mechanica Lite from the shaft part file, but was unable to constrain properly where the bearings would be or apply the moment properly. The best thing I could think of was to add blocks as shown below that would act to support the shaft and that would essentially serve as the bearings. In the testing. I was able to constrain these blocks.
http://i.imgur.com/ci25b.jpg
Now I'm trying to apply a moment, but the moment option is greyed out no matter what I select (shown below). I'm also unsure how to apply gravity. I would appreciate help in running this analysis. My end goal is to see how much I can hollow out the shaft to save on weight and maintain strength. Thanks.
http://i.imgur.com/j13P7.jpg





RE: Using Mechanica Lite to analyze stress in a rotating shaft
At a certain point I am pretty sure that the Lite will be very limited and your results may be inaccurate due to improper constraint definition and the lack of ability to handle stress singularities.
Hope any of that helps and good luck.
-J-
RE: Using Mechanica Lite to analyze stress in a rotating shaft
an alternative to Mechanica for this application is to look into the 1D shaft/bearing module of KISSsoft (http://www.kisssoft.ch/). You could build a shaft model and assign bearings at the specific locations, and get very quick results - including bearing lifetimes! Maybe it's overkill for your company in general to purchase it, but they do have a 30 day evaluation license which you could use to solve this problem & evaluate it for general use. Note, I am in no way affiliated with the company, I just loved using the software.
That having been said, I had a nice reply typed up until I realized that what I was recommending is only possible within Mechanica and not in Mechanica Lite (creating points with rigid links to the bearing blocks & allowing only translational DOF's to be fixed). If you have to use Mechanica Lite though, you may have better luck making the bearing blocks thinner so they don't impose as much of a rotation restriction on the shaft. Additionally, only one of the blocks should have all 3 DOF fixed; the rest should have only radial DOF's fixed.