Tagged: degree-of-freedom, error, stiffness-matrix, substructuring
May 30, 2022 at 3:55 pmVasily0616SubscriberI have a problem with calculating the stiffness matrix. Basically, I followed the instruction from the web, using the following codes, and have tried a relatively simple box design. In the end, I was able to get the matrix I needed.
But when it comes to my gearbox design, which is set 16 remote Points in the middle of the bearings and named in command, the same calculating way met some problems. Ansys reported the following error:
No MASTER degrees of freedom are specified. If the TOTAL command was used for automatic generation of MASTER degrees of freedom, it is invalid with the SPARSE solver in a substructure analysis. Please use the M command to define at least one MASTER degree of freedom.
This is a bit weird because as far as I know, I do use the M function in my code, which should specify the DOF. I expect a 96*96 stiffness matrix.
There is my APDL code.
Thanks a lot in advance!
May 31, 2022 at 1:39 pmChandra SekaranAnsys EmployeeIt sounds like somehow the M commands do not have valid node IDs specified. Add a *STAT command just before the DO loop like below to see if you have valid node ID numbers M1, M2, M3 etc. Also in the output see the response for "M" command. You can also add a MLIST at the end of the loop to see a list of Master DOFs.
June 1, 2022 at 7:47 amAshish KhemkaAnsys Employee
Please see if the following template helps:
4.1. Single Superelement Substructuring Template (ansys.com)
How to access the ANSYS Online Help ÔÇö Ansys Learning Forum
Regards Ashish Khemka
June 1, 2022 at 8:56 am
June 1, 2022 at 9:40 amAshish KhemkaAnsys Employee
For the error message there are 2 suggestions:
Please check if the remote point behavior is set "deformable", CMS won't recognize it as Master DOF and then give the error. To fix this change the behavior to "rigid" which uses MPC184 element and hence there is an element (MPC184) linked to the remote node not just some CE equations and then Master DOF would be recognized.
Another option is to create not only the single node but also the mass element type with a negligible mass.
Regards Ashish Khemka
- You must be logged in to reply to this topic.
Boost Ansys Fluent Simulations with AWS
Computational Fluid Dynamics (CFD) helps engineers design products in which the flow of fluid components is a significant challenge. These different use cases often require large complex models to solve on a traditional workstation. Click here to join this event to learn how to leverage Ansys Fluids on the cloud, thanks to Ansys Gateway powered by AWS.
Earth Rescue – An Ansys Online Series
The climate crisis is here. But so is the human ingenuity to fight it. Earth Rescue reveals what visionary companies are doing today to engineer radical new ideas in the fight against climate change. Click here to watch the first episode.
Subscribe to the Ansys Blog to get great new content about the power of simulation delivered right to your email on a weekly basis. With content from Ansys experts, partners and customers you will learn about product development advances, thought leadership and trends and tips to better use Ansys tools. Sign up here.
- Saving & sharing of Working project files in .wbpz format
- Solver Pivot Warning in Beam Element Model
- Understanding Force Convergence Solution Output
- An Unknown error occurred during solution. Check the Solver Output…..
- What is the difference between bonded contact region and fixed joint
- whether have the difference between using contact and target bodies
- The solver engine was unable to converge on a solution for the nonlinear problem as constrained.
- Colors and Mesh Display
- User manual
- material damping and modal analysis
© 2023 Copyright ANSYS, Inc. All rights reserved.