I have a set of data points from experimental observations. For each time step i already have the Strain Tensor and the Stress tensor.
So, starting from the strain tensor, reported as a matrix, how can i calculate the equivalent plasic strain?
The strain tensor is similar to the attached one.
Hi,
the equivalent plastic strain dual to the von-Mises equivalent stress is calculated from
eq = (4/3*Y2)1/2 ,
where
Y2 = 0.5*(e112 + e222 + e332 + 2*e122 + 2*e232 + 2*e132) ,
and eij are the components of the deviator of plastic strain:
eij = epsij - 1/3*(eps11 + eps22 + eps33)*deltaij ,
where epsij are the components of the plastic strain tensor and deltaij is the Kronecker delta. The von-Mises equivalent stress is
q = (3*J2)1/2 ,
where
J2 = 0.5*(s112 + s222 + s332 + 2*s122 + 2*s232 + 2*s132) ,
and sij are the components of the Cauchy stress deviator.
Regards
Reference: W. F. Chen, D. J. Han: Plasticity for Structural Engineers, Springer-Verlag New York, 1988
Hi,
the equivalent plastic strain dual to the von-Mises equivalent stress is calculated from
eq = (4/3*Y2)1/2 ,
where
Y2 = 0.5*(e112 + e222 + e332 + 2*e122 + 2*e232 + 2*e132) ,
and eij are the components of the deviator of plastic strain:
eij = epsij - 1/3*(eps11 + eps22 + eps33)*deltaij ,
where epsij are the components of the plastic strain tensor and deltaij is the Kronecker delta. The von-Mises equivalent stress is
q = (3*J2)1/2 ,
where
J2 = 0.5*(s112 + s222 + s332 + 2*s122 + 2*s232 + 2*s132) ,
and sij are the components of the Cauchy stress deviator.
Regards
Reference: W. F. Chen, D. J. Han: Plasticity for Structural Engineers, Springer-Verlag New York, 1988
The strain tensor you have is total strain or the total strain increment?
Generally when you want to work with small strain formulation then you procced incrementally. You need to decompose the total strain increment in elastic and plastic parts. This decomposition is based on the yield surface (model) you use. Generally the formulation is implicit and requires a return mapping algorithm. Once you get the incremental plastic strain, add it to the plastic strain tensor to get the total plastic strain and follow the procedure as mentioned by Daniel in the previous comment.
Dear Sir,
May be you can use ASME approach, to estimate plastic strain using elastic one.
it is a good and realstic manner to do
Greetings.
Mourad
Just out of curiosity: how did you get at the full stress and strain tensor from experimental observations? And if you have the full stress and strain tensors, what are your plans with the equivalent strain?
any one can help to solve a plasticity problem?
I got full elastic solution but some points exceeds the elastic limit according to Mises criterion how to get the real plastic solutions, knowing that the matreial stress-strain model is available.
Hi Ahmed El-Deeb you may be looking to use Neuber approximation or ESED appraoch by Glinka.
Some links below:
http://fde.uwaterloo.ca/Fde/Notches.new/neuber.html
http://www.iberisa.com/productos/winlife/pdf/Neuber_FEA.pdf
http://www.pragtic.com/PragTicHelp/files/%7B4D1B8440-3DE3-4D53-9DC0-6624352331C0%7D.htm
Regards,
Nicolas
Dear Sir
We have a material PP matrix reinforced with PP 0/90 Fibers. This means E1=E2 but not E3. We have stress strain curves for 1,2,3 directions, E1,E2, E3, and strengths in three directions. But the material behavior is elastic-plastic. Can we model this material in ABAQUS without using a user defined material subroutine?
The stress-strain curve is shown in attached file.
Thank You in advance
Imran Ali
any one can help md to get plastic strain in line element ansys WB?
I make beam elemen with line element that have crossection (profil). So I think it representation beam element. finally, I got equivalent stress in line element that have crossection rectangle but ANSYS WB say not supported to calculate plastic strain in line element. Any body can help me that is right or not?
thanks lot
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