I do not completely understand the concept of rigid body modes for constrained models. How come there are rigid-body modes if the rotor is not freely-supported or even in free-free condition?
Hi Ilya. Yes, I'm familiar with using Ansys to solve rotordynamics. But, Ansys is rather cumbersome to model and to perform rotordynamic tasks. So, I prefer to use XLRotor software or other simpler tools.
It is possible that your problem does not exhibit a cylindrical mode. The existence and nature of different mode shapes depend on the specific geometry, boundary conditions, and material properties of the system you are analyzing. If the symmetry of your system is not cylindrical, or if the boundary conditions are such that cylindrical modes are not excited, then it is possible that you will not observe any cylindrical modes in your solution. Additionally, if the material properties of your system are anisotropic, this can also affect the type and number of mode shapes that are present. However, it is also possible that a cylindrical mode may be present but not captured in your analysis due to the specific details of your numerical approach or the accuracy of your modeling assumptions. It may be worth exploring different numerical techniques or refining your mesh to see if any additional mode shapes can be identified.
Very good video explanation. I like all your videos, please keep posting. I have few questions 1. The XLRotor feature for Excel is your own program? Is it available for me to check it out? 2. Do you do stability analysis as well as per API 684 where you check the logarithmic decrement value? Thank you!
Hi Amir. It is good to hear from you. I will keep posting videos while I can. Here are answers to your questions. 1. XLRotor is commercial software. So, you could purchase them at their website. 2. Yes, I do stability analysis as per API spec. API spec is a great guideline for designing turbomachinery. But, API spec is not strictly followed by other industries (such as HVAC, Medical devices, and etc).
Thank you for your comment! I'm glad you found my video helpful. Regarding the software you mentioned, you may want to try contacting the software's official support team for assistance. Here is the link to the website: www.xlrotor.com/
