disla

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disla
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  • -Isn't Cyclic symmetry and elastic supports on both symmetry faces redundant BC?. -I miss the internal pressure on the gasket it self. -There is an elastic support applied to the inside area of the gasket and bolt which seems unrealistic. -Symmetry…
  • I don't know how to output modal analysis results in this conditions @sofien_73 That should be under solution/MechanicalMisc/Modal effective Mass and Modal effective Mass fraction for a frequency analisys. I haven't tested on your problem so I …
  • According to the manual Mecway can also output the Modal effective mass fraction which is modal effective mass expressed as a faction of the total free mass.
  • Hi sofien, Based on this: ->reactions are the same (I assume you mean in the static solution) ->mode shapes and frequency are the same I can only think that you are using a larger number of modes for the modal superposition which would inc…
  • in S4R elements Comment by disla April 24
  • I don't use S4R at all. I have also found discrepancies with reference benchmarks when used for Buckling analysis.
    in S4R elements Comment by disla April 24
  • You can, but keep in mind you should set up the problem as nonlinear for accurate results if you expect large displacement. Main elements involved are rotating. Rotations---->NLGEOM. Check overall force balance.
  • No problem with your set up. This is a known limitation of the calculix S4R formulation. There is a strong shear MODE III present in the benchmark which S4R (Expanded C3D8R) is not suitable for.
    in S4R elements Comment by disla April 23
  • Hi, Sebastian, Have you take a look at Mortar contact?. I have obtain clearanes of 1E-35 with reasonable times. There is some limitations due to units conversion but results are really good when it works.
  • A good starting point is E*50 but there is no general rule. My recomendation if there could be one is to keep contact clearance at least of 0.1% of the caracteristic element size in the normal direction to the contact area.
  • All geometries have initial penetration. Some contact definitions are solved as an interference fit. take a look at the adjust parameter.
    in CXX Contact Comment by disla March 6
  • I'm in particular referencing to this convention. Are shears (gammas) , ccx output strains x 2 ? EDITED: SOLVED. I have seen in the FRD the value in the GUI is Twice the value in the FRD. Thanks. Is that for consistency with Openradioss?
  • @Sebastianmaklary Hi, I did not respond you just because I saw the Kuhl example file. Let me know if you need any further help. Regards.
  • Looks fine to me although the stiffness value of the base look unnecessary high. I guess you are looking for a hard contact behavior?. Note there is only compression in the part of the base that is pushed up and compressed against the base. Node…
  • Not the same. Let's see if I can explain with my poor English. ChatGPT doesn't understand me. An only compression support creates a set of elements in which the surface is supported. "Like" regular springs but nonlinear in this case. They only wor…
  • It works great transfering only compresion in between the parts in the hole area. This machine has three of this set ups and it converge nicely. Principal Stress 1 (Tensle) and 3 (Red_Compressive).The piece is free to move .
  • Hi Forced convection maybe?. There are some examples in the forum and explained in the manual. Regards
  • Welcome to the forum Rudolf
  • Yep, it would be a bit confusing. Considering that w is the transverse direction, (also the normal vector for shells), maybe it would be more convenient to change the GUI input to Angle about W instead of U. Kind of a "rotation of actual definition…
  • I think that for prismatic/cylindrical shapes it can be easier to set a general orientation like the one in my previous post and then play with the degrees option to adjust the +-45 or whatever for each layer.
  • According to your picture, if geometry is centered at zero , you can get a radial distribution of orientations with:
  • Not sure if you know Element orientation can be coordinate dependent.
  • It seems to fail much way sooner. Elements sizes below approx. 3mm (0.003)when the inp is expressed in meters. I will post in ccx forum before github to confirm.
  • Hi Victor, Once scaled (with all node dimensions bigger than 1) I have modeled MORTAR with pefect HARD. The agreement is so perfect that everithing black bloack Clearance zero. Mortar (ccx) has some issues when it deals with small numbers. Seems …
  • Don't know why but the problem solves if it is scaled by 1000.¿?¿
  • Files: contact4_mortar.inp Result when run in the monitor. Files: MECWAY_Contact4_mortar.liml Green window but no resuts.
  • Regarding RF on the REF node , there is a bug in 2.22 that has been fixed in the last ccx version 2.23. https://calculix.discourse.group/t/ref-node-of-pretension-section-reaction-force/3759
  • HI, Have you noticed that Contact State doesn't give a solution when the quasiestatic option is active. There is a message of unknown reason.
  • Thanks Victor. I will pay more attention to the ramp. Regarding the Pretension Ref Node I will also ask in the Calculix forum to see if someone has a clue of why RF value doesn't match.
  • It should be RF= Pretension section Load resultant. This is not right sorry. As RF contains the sum of external forces RF should be Zero. In any case the value is unnexpected.
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