error distorione ansys

[petrelli9]

salve, ricevo il seguente errore dopo una simulazione di compressione,
*** error *** cp = 1773.109 time= 15:35:42
element 105104 (type = 3, solid187) (and maybe other elements) has
become highly distorted. excessive distortion of elements is usually
a symptom indicating the need for corrective action elsewhere. try
incrementing the load more slowly (increase the number of substeps or
decrease the time step size). you may need to improve your mesh to
obtain elements with better aspect ratios. also consider the behavior
of materials, contact pairs, and/or constraint equations. please rule
out other root causes of this failure before attempting rezoning or
nonlinear adaptive solutions. if this message appears in the first
iteration of first substep, be sure to perform element shape checking.
*** load step 3 substep 1 not completed. cum iter = 43
*** begin bisection number 1 new time increment= 0.33333e-02,

qualcuno mi sa dire il perchè? ho già attivato le grandi deformazioni, sto provando ad aumentare il numero di substeps ma non so se riuscirò a risolvere. in allegato l'ultimo stadio prima del blocco

 

[meccanicamg]

salve, ricevo il seguente errore dopo una simulazione di compressione,
*** error *** cp = 1773.109 time= 15:35:42
element 105104 (type = 3, solid187) (and maybe other elements) has
become highly distorted. excessive distortion of elements is usually
a symptom indicating the need for corrective action elsewhere. try
incrementing the load more slowly (increase the number of substeps or
decrease the time step size). you may need to improve your mesh to
obtain elements with better aspect ratios. also consider the behavior
of materials, contact pairs, and/or constraint equations. please rule
out other root causes of this failure before attempting rezoning or
nonlinear adaptive solutions. if this message appears in the first
iteration of first substep, be sure to perform element shape checking.
*** load step 3 substep 1 not completed. cum iter = 43
*** begin bisection number 1 new time increment= 0.33333e-02,

qualcuno mi sa dire il perchè? ho già attivato le grandi deformazioni, sto provando ad aumentare il numero di substeps ma non so se riuscirò a risolvere. in allegato l'ultimo stadio prima del blocco

Is it that if you make the smallest mesh you solve?

 

[biz]

Tell you where the problem is. improves the quality of the grid and/or make more subdivisions.
the mesh so to the eye is of poor quality for such work.

 

[Saso93]

salve, ricevo il seguente errore dopo una simulazione di compressione,
*** error *** cp = 1773.109 time= 15:35:42
element 105104 (type = 3, solid187) (and maybe other elements) has
become highly distorted. excessive distortion of elements is usually
a symptom indicating the need for corrective action elsewhere. try
incrementing the load more slowly (increase the number of substeps or
decrease the time step size). you may need to improve your mesh to
obtain elements with better aspect ratios. also consider the behavior
of materials, contact pairs, and/or constraint equations. please rule
out other root causes of this failure before attempting rezoning or
nonlinear adaptive solutions. if this message appears in the first
iteration of first substep, be sure to perform element shape checking.
*** load step 3 substep 1 not completed. cum iter = 43
*** begin bisection number 1 new time increment= 0.33333e-02,

qualcuno mi sa dire il perchè? ho già attivato le grandi deformazioni, sto provando ad aumentare il numero di substeps ma non so se riuscirò a risolvere. in allegato l'ultimo stadio prima del blocco

Hi.

if I have not understood badly you should improve the quality of your mesh to try to solve the problem --> "you may need to improve your mesh to obtain elements with better aspect ratios".
I think I can help you (if any) a filter for the elements. ascpect ratio --> are the little "linear" elements that send you ko the calculation, for example a triangle scale with a side 3 odg different than the other two sides.
try to correct these elements and see whether the calculation still diverges or not

 

[petrelli9]

I thank you all for the answers, reducing the mesh I can distort the try even more, but at the time when two triangles of the same face touch each other, the error comes out. I wanted to know if you know how to help me with breaking criteria, maybe by entering one the test breaks exactly as reality and simulation comes to an end. Thank you.

 

[meccanicamg]

a test to break as in reality you have to make a nonlinear simulation as next application of load and above all you do not have to stay only in the linear elastic field but you have to go to the plastic head....so at least a behavior with two bilinear curves.
definitely something more complicated than the excavated fem analysis to small shift.
Are you sure you want to get there?

 

[biz]

I thank you all for the answers, reducing the mesh I can distort the try even more, but at the time when two triangles of the same face touch each other, the error comes out. I wanted to know if you know how to help me with breaking criteria, maybe by entering one the test breaks exactly as reality and simulation comes to an end. Thank you.

You should try using the xfem, which basically refers to fracture mechanics. not knowing the sw in question I am not able to help you.

 

[petrelli9]

I explain to you, in essence I have carried out compression tests on samples with "lattice" structure (yellow orange and grey curves) , I managed to reproduce the elastic part (blue line with balls), but now I should try to "break it" or however to lower the stress. The only thing that comes to mind is a rupture criterion that, once you get to a certain value of stress, makes me break the test. would you tell me a way?

 

[petrelli9]

in practice this is the last step I can reproduce, then it gives me error.