warning messages in implicit analysis
warning messages in implicit analysis
(OP)
hello everyone,
I am modeling the axisymmetric tube hydroforming of aluminium tube by implicit analysis, the pressure is varied upto 22 MPa
For higher pressure from 15 MPa onwards I get the warning messages
The strain increment has exceeded fifty times the strain to cause first yield at 1331 points
The plasticity/creep/connector friction algorithm did not converge at 877 points
Convergence judged unlikely. Increment will be attempted again with a time increment of 2.25508e-03
FORCE equilibrium accepted using the alternate tolerance.
I have tried using a fixed time increment of 0.0001 but job is aborted
Is there any problem in material properties or in the step?
Thank you in advance
I am modeling the axisymmetric tube hydroforming of aluminium tube by implicit analysis, the pressure is varied upto 22 MPa
For higher pressure from 15 MPa onwards I get the warning messages
The strain increment has exceeded fifty times the strain to cause first yield at 1331 points
The plasticity/creep/connector friction algorithm did not converge at 877 points
Convergence judged unlikely. Increment will be attempted again with a time increment of 2.25508e-03
FORCE equilibrium accepted using the alternate tolerance.
I have tried using a fixed time increment of 0.0001 but job is aborted
Is there any problem in material properties or in the step?
Thank you in advance





RE: warning messages in implicit analysis
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RE: warning messages in implicit analysis
RE: warning messages in implicit analysis
Are you new to this forum? If so, please read these FAQ:
http://www.eng-tips.com/faqs.cfm?fid=376
http://www.eng-tips.com/faqs.cfm?fid=1083
RE: warning messages in implicit analysis
I'll try your suggestion
RE: warning messages in implicit analysis
Make sure that the maximum stress of your plasticity data isn't reached in the analysis.
RE: warning messages in implicit analysis
RE: warning messages in implicit analysis
RE: warning messages in implicit analysis
amplitude curve is tabular type
time amp
0 0
1 1
no warning appears here for max load increment of 0.0005
now i changed the amp curve
time amp
0 0
0.4 1
1 1
warning appears here for max load increment of 0.00025
RE: warning messages in implicit analysis
RE: warning messages in implicit analysis
RE: warning messages in implicit analysis
I have resolved the warning problem by limiting the max time increment to 1e-4 but for peak pressure the mises stress is around 291.8 MPa and PEEQ = 0.2 whereas my input stress = 263 Mpa and strain = 0.25. I am not applying rate dependent plasticity, the material obeys hill's normal anisotropy so I have used potential for R11,R22,etc. how is this possible?
RE: warning messages in implicit analysis