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How to obtain a distance (mm) for my permanent strain with strain result ?

Experimenter

Hi everyone,

Maybe the answer for my question is obvious but how do I have a distance (mm) for my permanent strain with strain result.

Infact, with the strain equation you have ε = Δl / l0My strain result (Nonlinear Strain - Element Nodal with average) in NX is 0.0036 for one particular node that I chose. So, I have ε = 0.0036. How can I find my Δl ?

l0 is my distance from my node to absolut origin ? I don't understand how convert my strain result in distance.

6 REPLIES

Re: How to obtain a distance (mm) for my permanent strain with strain result ?

Siemens Phenom

The nodal strains would need to be integrated across the elements using shape functions to get the displacements (Δl).

Why don't you obtain the displacements directly from the solution?

Re: How to obtain a distance (mm) for my permanent strain with strain result ?

Experimenter

Hi JimB,

Thanks for the answer. But how can I obtain directly my displacement ? Because if I use Displacement - Nodal I have my the displacement of my node with the load for the step that I choose.  But I would like to obtain my depth in mm of my permanent strain when the load is off.

Re: How to obtain a distance (mm) for my permanent strain with strain result ?

Siemens Phenom

It sounds like you only have subcases where loads are applied. You need to add an additional unloading subcase where no loads are specified. The displacements in this subcase will be your permanent plastic deformation (assuming that plasticity is the only material nonlinearity).

Re: How to obtain a distance (mm) for my permanent strain with strain result ?

Experimenter

Thanks, but I work with SOL 601,106 (sorry I should have specify it earlier) because I use 3D contact (only 2 pieces). So create new subcase is not possible. I use a function to applied the load (0s --> 0N to 1s --> 429N).

Do I have to change it to 0s --> 0N , 0.5s --> 429N, 1s -->0N ? The result will be the same ?

Re: How to obtain a distance (mm) for my permanent strain with strain result ?

Siemens Phenom

Yes, in solution 601, you would ramp your loads back down with additional points in the load history curve.

You could do either 0s --> 0N to 1s --> 429N to 2s --> 0N  or   0s --> 0N , 0.5s --> 429N, 1s -->0N. There will be no difference if everything is static.

Re: How to obtain a distance (mm) for my permanent strain with strain result ?

Experimenter

Ok thank you very much for your help