January 13, 2023 at 8:56 pm
January 13, 2023 at 9:32 pm
January 14, 2023 at 1:33 pmpeteroznewmanSubscriber
It is possible to increase the Force Criterion value, but you should first look for the reason why the Force Convergence line is not dropping below the Criterion line and take corrective action first.
Under the Solution branch click on the Solution Information folder. In the Details window is a line that says Newton-Raphson Residuals. The default is 0 but type in a number such as 3 or 4. This will cause 3 or 4 plots to be saved under the Solution Information folder which show the residual force imbalance in the mesh for the last 3 or 4 iterations. Look at the plots and zoom in on the location with the Maximum value. This location needs smaller, better quality elements. If you remesh to achieve that, the convergence will often be achieved. Sometimes these plots will have the Max value in the same place, but other times the Max value will jump around to different locations.
Here is an article on convergence.
In your reply, please paste an image of the plot around the location of the Max value of the Newton-Raphson Residual for the current mesh and another image to show the improved mesh and let us know if the model now converges. Improving the mesh is how you get an accuracte solution. Relaxing the Force Criterion means you are accepting less accuracy in the solution.
Here is a thread on how to change the Criterion.
January 17, 2023 at 8:24 am
January 17, 2023 at 8:25 am
January 17, 2023 at 8:18 amRiccardo PetrelliSubscriber
The sudden increase in value is due to the elimination of the element that exceeds a certain stress and strain threshold (actually with the command estif 0.5 I am lowering its stiffness). I am attaching my script.total_steps=20subst_int=10subst_max=18subst_min=10neqit, 120 !numero massimo di iterazioni di default è impostato su 15*do,i,1,total_steps/goprtime_step=i/total_stepstime,time_stepnsubst,subst_int,subst_max,subst_minoutres,all,allesel,allsolvefinish/post1set,lastesel,alletable,stress,s,eqvesel,s,etab,stress,ARG1! *get,stress_ecount%i%,elem,0,countcm,kill_stress%i%,elemcmsel,s,kill_stress%i%,elem! *get,stress_ecount%i%,elem,0,countesel,alletable,strain,epto,eqvesel,s,etab,strain,ARG2! *get,strain_ecount%i%,elem,0,countcm,kill_strain%i%,elemcmsel,s,kill_strain%i%,elem! *get,strain_ecount%i%,elem,0,countallselcmwrite,kill_list,cmparsav,allfinish/soluantype,,restartparres! *status/input,kill_list,cm*do,k,1,iestif, 0.5 !moltiplica la matrice di rigidezza di 0.5ekill,kill_stress%k%ekill,kill_strain%k%! *status*enddo*enddofinishmy value for stress eq is 1750 and strain 0,032note that the number of steps is not the one written in the script, because I don’t remember it for this case.
January 26, 2023 at 11:02 pm
- You must be logged in to reply to this topic.
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
- An Unknown error occurred during solution. Check the Solver Output…..
- Understanding Force Convergence Solution Output
- Solver Pivot Warning in Beam Element Model
- Colors and Mesh Display
- How to calculate the residual stress on a coating by Vickers indentation?
- whether have the difference between using contact and target bodies
- What is the difference between bonded contact region and fixed joint
- The solver engine was unable to converge on a solution for the nonlinear problem as constrained.
- User manual
© 2023 Copyright ANSYS, Inc. All rights reserved.