September 21, 2022 at 9:30 pmvkr535Subscriber
I was trying to model a 2d heat conduction of a rectangular plate with all edge neumann boundary conditions as given in the example 4.9 in the attached pdf. This problem is ill posed and may be solved using the additional constraint as suggested. I was trying to reproduce this problem in ANSYS and see if i could solve, but i couldn't do it as the solver catches the pivot error. I attached the snapshot of the model, which is a rectangular plate with length, L and width W. The bottom edge is subjected to non-zero flux condition, while all other edges are insulated(zero-flux).
1. The basic idea was to augment the exiting stiffness matrix with extra dof's and then use the additional constraint. So, firstly I meshed the plate with plane55 elements. Then I tried to increase the dof of the model, by adding the extra nodes at the bottom edge and create the combin14(thermal dof) elements with zero stiffness connecting the domain nodes at the bottom edge to the newly created extra nodes.
2. I then applied the constraint equation(CE) to the newly created nodes as per the eqn(4.129).
I end up with the pivot error issue and couldnt make it work. I wrote the APDL input below wherein i tried to use the above approach.
Could you take a look ino this issue and let me know if its possible to solve this
pi = ACOS(-1.0)
*VGET,sft,NODE, ,NSEL,, , ,2
September 22, 2022 at 11:05 amAshish KhemkaAnsys Employee
The pivot error indicates that the temperature is exceeding in the body. Can you try specifying the temperature boundary conditions as well?
September 22, 2022 at 6:27 pmvkr535Subscriber
Thank you for the feedback.
There is no dirichlet bc's(temperature) for this problem. The idea was to simulate the pure neumann problem as in that example 4.8 using the additional constraint condition. If there is a dirichlet(temperature), there is no issue with the solvability.
I was wondering if there is a any issue with modeling using the combin14 at the boundary where i specify non-zero flux and satify the constraint condition.
- You must be logged in to reply to this topic.
Simulation World 2022
Check out more than 70 different sessions now available on demand. Get inspired as you hear from visionary companies, leading researchers and educators from around the globe on a variety of topics from life-saving improvements in healthcare, to bold new realities of space travel. Take a leap of certainty and check out a session today here.
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.
- Error with workbench SceneGraphChart
- Workbench error
- Workbench not opening
- How can I renew ANSYS student version license?
- License Error
- An error occurred when the post processor attempted to load a specific result.
- Licensing error while opening ANSYS Mechanical
- Licensing Error
- Problem with FlexNet Licensing
- ConfigureThisMachine Returns Error 1