How to calculate residual stress from plastic strain tensor in abaqus?

[Lemine]

Doing a cyclic calculus in Abaqus and at the beginning of each cycle I apply an initial plastic strain, we know that when we apply initial plastic that implies the presence of stress resulting from the plastic deformation, but Abaqus always show initial stress null at the beginning of the cycle.
Thanks in advance for helping me to overcome this problem.

Best regards,

 

[FEA way]

For what purpose do you define the initial plastic strains at the beginning of each cycle - what are the effects that you want to model ?

To see how it works, check some examples from the documentation where this option is used. You can find them with the following command:

abaqus findkeyword

then type: Initial conditions, type=plastic strain

Particular input files can be extracted using abaqus fetch command (provide the name of the inp file as a value of job parameter).

 

[Lemine]

Thanks for your response, Yes I use the keyword *Initial conditions, type=plastic strain, to define the initial plastic strain but my question is that regardless of the value of the initial plastic strain applied the initial stress is shown always zero in Abaqus and this is not right? so how to calculate initial stress from initial plastic strain. Thanks a lot

 

[NRP99]

Did you exactly specified the strain components? As given in this Link.

Make sure the syntax is correct of the input command.

 

[Lemine]

Thanks for your response, yes it's verified and tested, but the problem above remains. Thanks for your help

 

[NRP99]

May this help -thread799-398655 or search this forum for any solution.

 

[FEA way]

Test on a simple model (such as a classic single element test) could help you understand what's going on in this case. I also mentioned the documentation examples before so that you could see how it works there.

My question regarding the reason for the use of initial plastic strains in this case was meant to find out if you actually need this option (maybe another modeling approach could be used) and if you use it properly. Basically, I wanted to know what the source of these strains is in the modeled structure.

 

[Mustaine3]

Thanks for your response, Yes I use the keyword *Initial conditions, type=plastic strain, to define the initial plastic strain but my question is that regardless of the value of the initial plastic strain applied the initial stress is shown always zero in Abaqus and this is not right? so how to calculate initial stress from initial plastic strain. Thanks a lot

Your starting condition is not in equilibrium and Abaqus calculates that within the first step. This will generate the stresses. Add an additional static step at the beginning if you want to see this separately.

Or you calculate the stresses yourselves with the stress-strain curve and also apply that as initial condition.

 

[Lemine]

Thanks to all for your response,


Thanks, Mustaine for your suggestion, I try to create the initial static step in Abaqus, in this step, I just define the initial plastic strain and I didn't apply any load, and the result is still the same at the end of the step "Stress always zero", can you give more clarification on this proposition or the other method you suggest.

Many thanks to all.