Buckling Analyse with INREL-2 and MATS1
Altair EmployeeHello,
i have a Problem with a buckling Analyse:
There is a Aluminium Piece with three bores. In each bare there is a RBE3 with Loads and moments in every direction (xyz). The model is fixed by PARAM AutoSPC=YES and INREL=-2. The question is: How much plastic Deformation will be left after the load is being applied and than decreased to 0...
I tried it with two Non-Linear quasi-static loadsteps and MATS1 Material as a table.
The Analysis is runing until 50-60% of the load is reached and than gives this error:
*** ERROR # 4965 ***
Maximum number of time increment cutbacks reached,
analysis aborted.
It appears because 5 approaches to correct the foregone load increment. It seems, that the plastic Deformation starts at that Point and it expands extremly fast:
Starting load increment 88 Current increment 9.8192E-008
Subcase 6 Load step: 5.5889E-01
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Nonlinear Error Measures Gap and Contact Element Status Maximum
Iter Avg. U EUI EPI EWI Open Closed Stick Slip Frozen Plststrn
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1 5.97E-03 1.00E-03 2.31E-05 3.12E-08 0 0 0 0 0 5.93E-02
2 2.80E-03 1.46E+00 2.85E-01 8.33E-01 0 0 0 0 0 3.91E-02
3 3.85E-03 3.40E-01 1.19E-01 7.60E-02 0 0 0 0 0 9.51E-02
4 7.48E-03 1.24E+00 5.51E+00 6.39E+00 0 0 0 0 0 2.22E+00
5 1.34E-02 7.32E-01 5.55E+02 5.23E+02 0 0 0 0 0 7.95E+00
Adjusting load increment 88 (correction #1), Current increment 2.4548E-008
Subcase 6 Load step: 5.5889E-01
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Nonlinear Error Measures Gap and Contact Element Status Maximum
Iter Avg. U EUI EPI EWI Open Closed Stick Slip Frozen Plststrn
--------------------------------------------------------------------------------
1 5.97E-03 1.00E-03 2.31E-05 3.12E-08 0 0 0 0 0 5.93E-02
2 2.80E-03 1.46E+00 2.85E-01 8.33E-01 0 0 0 0 0 3.91E-02
3 3.85E-03 3.40E-01 1.19E-01 7.60E-02 0 0 0 0 0 9.51E-02
4 7.49E-03 1.24E+00 5.51E+00 6.39E+00 0 0 0 0 0 2.23E+00
5 9.59E-03 7.22E-01 1.96E+03 1.27E+03 0 0 0 0 0 8.26E+00
Adjusting load increment 88 (correction #2), Current increment 6.1370E-009
Subcase 6 Load step: 5.5889E-01
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Nonlinear Error Measures Gap and Contact Element Status Maximum
Iter Avg. U EUI EPI EWI Open Closed Stick Slip Frozen Plststrn
--------------------------------------------------------------------------------
1 5.97E-03 1.00E-03 2.31E-05 3.12E-08 0 0 0 0 0 5.93E-02
2 2.80E-03 1.46E+00 2.85E-01 8.33E-01 0 0 0 0 0 3.91E-02
3 3.85E-03 3.40E-01 1.19E-01 7.60E-02 0 0 0 0 0 9.51E-02
4 7.49E-03 1.23E+00 5.51E+00 6.38E+00 0 0 0 0 0 2.23E+00
5 9.73E-03 7.17E-01 1.02E+03 7.05E+02 0 0 0 0 0 7.19E+00
Adjusting load increment 88 (correction #3), Current increment 1.5343E-009
Subcase 6 Load step: 5.5889E-01
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Nonlinear Error Measures Gap and Contact Element Status Maximum
Iter Avg. U EUI EPI EWI Open Closed Stick Slip Frozen Plststrn
--------------------------------------------------------------------------------
1 5.97E-03 1.00E-03 2.31E-05 3.12E-08 0 0 0 0 0 5.93E-02
2 2.80E-03 1.46E+00 2.85E-01 8.33E-01 0 0 0 0 0 3.91E-02
3 3.85E-03 3.40E-01 1.19E-01 7.60E-02 0 0 0 0 0 9.51E-02
4 7.49E-03 1.23E+00 5.51E+00 6.38E+00 0 0 0 0 0 2.23E+00
5 9.78E-03 7.18E-01 2.99E+03 2.15E+03 0 0 0 0 0 8.65E+00
Adjusting load increment 88 (correction #4), Current increment 3.8356E-010
Subcase 6 Load step: 5.5889E-01
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Nonlinear Error Measures Gap and Contact Element Status Maximum
Iter Avg. U EUI EPI EWI Open Closed Stick Slip Frozen Plststrn
--------------------------------------------------------------------------------
1 5.97E-03 1.00E-03 2.31E-05 3.12E-08 0 0 0 0 0 5.93E-02
2 2.80E-03 1.46E+00 2.85E-01 8.33E-01 0 0 0 0 0 3.91E-02
3 3.85E-03 3.40E-01 1.19E-01 7.60E-02 0 0 0 0 0 9.51E-02
4 7.50E-03 1.23E+00 5.51E+00 6.38E+00 0 0 0 0 0 2.23E+00
5 9.79E-03 7.18E-01 5.96E+02 4.02E+02 0 0 0 0 0 6.46E+00
Adjusting load increment 88 (correction #5), Current increment 9.5891E-011
Subcase 6 Load step: 5.5889E-01
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Nonlinear Error Measures Gap and Contact Element Status Maximum
Iter Avg. U EUI EPI EWI Open Closed Stick Slip Frozen Plststrn
--------------------------------------------------------------------------------
1 5.97E-03 1.00E-03 2.31E-05 3.12E-08 0 0 0 0 0 5.93E-02
2 2.80E-03 1.46E+00 2.85E-01 8.33E-01 0 0 0 0 0 3.91E-02
3 3.85E-03 3.40E-01 1.19E-01 7.60E-02 0 0 0 0 0 9.51E-02
4 7.50E-03 1.23E+00 5.51E+00 6.38E+00 0 0 0 0 0 2.23E+00
5 9.80E-03 7.18E-01 5.47E+02 4.05E+02 0 0 0 0 0 6.67E+00
*** ERROR # 4965 ***
Maximum number of time increment cutbacks reached,
analysis aborted.
Saved the last (NOT-CONVERGED!) iteration for diagnostics.
*** Nonlinear solution failed to converge for Subcase 6 ***
NONLINEAR ITERATION SUMMARY FOR Subcase 7
Continuing nonlinear solution from Subcase 6
Subcase 6 did not converge - cannot continue.
Saved the last (NOT-CONVERGED!) iteration for diagnostics.
Maximum Plastic Strain at 6,67mm in itteration 5, that is way to high...
Does someone already had this Problem or some advice for this sort of buckling analyse?
Thank You and best regards
HyperName
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Answers
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Hi,
Is it possible to share the model file?
If yes, please use the file transfer link in my signature below.
0 -
Hi,
found the Problem: due to mesh size there was singularity ('Singularität' in german...)
Started the job two hours ago. Now OptiStruct makes an increment each by 4.0356E-007:
Starting load increment 118 Current increment 1.6142E-006 Subcase 6 Load step: 9.3278E-01 -------------------------------------------------------------------------------- Nonlinear Error Measures Gap and Contact Element Status Maximum Iter Avg. U EUI EPI EWI Open Closed Stick Slip Frozen Plststrn -------------------------------------------------------------------------------- 1 1.21E-03 6.90E-05 1.56E-06 1.01E-07 0 0 0 0 0 1.25E-02 2 1.24E-03 2.48E-02 5.34E-05 1.32E-03 0 0 0 0 0 1.32E-02 3 1.15E-03 1.02E-01 1.59E-03 2.00E-01 0 0 0 0 0 1.25E-02 4 1.21E-03 6.74E-02 1.50E-04 2.19E-02 0 0 0 0 0 1.25E-02 Adjusting load increment 118 (correction #1), Current increment 4.0356E-007 Subcase 6 Load step: 9.3278E-01 -------------------------------------------------------------------------------- Nonlinear Error Measures Gap and Contact Element Status Maximum Iter Avg. U EUI EPI EWI Open Closed Stick Slip Frozen Plststrn --------------------------------------------------------------------------------Maximum Plasic Strain looks good so far... can I give OptiStruct an limitation of the increment size? Like min. 1.00E-005 ?
@Prakash Pagadala: I'm Sorry, the model is commercial and not approved to be shared.
Thanks and Regards
0