Nonlinear analysis convergence problem
Nonlinear analysis convergence problem
(OP)
Hi all,
I'm currently trying to run a nonlinear static analysis of an engine mount using this simplified 3D geometry:
http://fi les.engine ering.com/ getfile.as px?folder= 30af0da1-f 149-401a-8 379-c0a354 242aa3& ;file=Unde formed.JPG
The material model is assumed to be a linear elastic one with a Young's Modulus of 2.5 MPa and a Poisson ratio of 0.45 (I'm using hybrid linear elements to prevent the problems related to the almost incompressible behavior of the material).
Although the fact that I've tried several material properties and analysis controls, I've not been able to achieve a complete analysis (there are frequent negative eigenvalues warnings and the analysis fails due to a excessively small "time" increment being used).
A curious aspect is the fact that the analysis always stops in the same deformed position:
http:// files.engi neering.co m/getfile. aspx?folde r=8514fcf3 -6253-400b -826c-b5b3 3573f5c2&a mp;file=De formed.JPG
(Please note that I've removed all contact interactions in order to simplify the model)
Does anyone have any idea for what might be wrong?
Thanks in advance,
koenigsegg
I'm currently trying to run a nonlinear static analysis of an engine mount using this simplified 3D geometry:
http://fi
The material model is assumed to be a linear elastic one with a Young's Modulus of 2.5 MPa and a Poisson ratio of 0.45 (I'm using hybrid linear elements to prevent the problems related to the almost incompressible behavior of the material).
Although the fact that I've tried several material properties and analysis controls, I've not been able to achieve a complete analysis (there are frequent negative eigenvalues warnings and the analysis fails due to a excessively small "time" increment being used).
A curious aspect is the fact that the analysis always stops in the same deformed position:
http://
(Please note that I've removed all contact interactions in order to simplify the model)
Does anyone have any idea for what might be wrong?
Thanks in advance,
koenigsegg





RE: Nonlinear analysis convergence problem
corus
RE: Nonlinear analysis convergence problem
The non-linearity is purely geometrical (due to large deformations). As to the boundary conditions, I've applied an encastre to the peripheral cylindrical surface and there is a concentrated load applied in the x marked point (a reference point associated to a rigid discrete surface). Although some of my previous analysis had contact interactions, this one doesn´t have any (apart from the tie contraint between the 3D solid body and the discrete rigid surface mentioned).
Thanks in advance,
koenigsegg
RE: Nonlinear analysis convergence problem
Rob Stupplebeen
RE: Nonlinear analysis convergence problem
corus
RE: Nonlinear analysis convergence problem
Unfortunatly no such messages appear.
Thanks,
koenigsegg
RE: Nonlinear analysis convergence problem
I've also thought of that, but when I tried applying a fixed displacement instead of a load the analysis stopped in the same position as before.
Thanks,
koenigsegg
RE: Nonlinear analysis convergence problem
corus