Learning Forum

[MLS MLS]

Hello,

I'm trying to correlate low cycle fatigue test stress-strain results with simulation results on Ansys Mechanical but i'm not able to have tehs ame results due to wrong FEA model.
I'm trying to compare the hysteresis loop from test with simulation resuts as shown in the example below. 

My Simulation Conditions are :
Cube of 1mm x 1mm x 1mm
Material : Young Modulus = 200Gpa, Poisson ratio = 0.28, Chaboche parameters in the capture below.
BC : Displacement on one side and Fixed Support on the opposite side.
Loading : sine wave with 0.01 amplitude, Frequency 1Hz.

Test Conditions are:
Low Cycle Fatigue Test, ASTM E606, Strain-Controlled, Delta Epsillon = 5%, Frequency = 1Hz
Rounded Specimen, Diameter of 10mm and Gauge Length of 15mm.

I'm not sur about the FEA model to use in order to correlate the LCF test results and which stress and strain to extract from Ansys.

Anyone has already performed this in Ansys ? Thank you for the help.

[mrife]

Hi MLS MLS

Which metal plasticity model did you use?  Only the elastic properties are shown.  Mike

[MLS MLS]

 

Hi Mike,

I only used elastic properties : Young Modulus of 200Gpa and Poisson ratio of 0.28.

Should I use a plasticity model or they are already included in the Chaboche parameters C and gamma ?

If I should use a plasticity model, can I use the Multilinear Isotropic Haredning since I have plastic deformation from the tensile test ?

Thank you

 

[mrife]

Hi MLS MLS

Yes for what I understand of your modeling needs the Chaboche material model is added to a metal plasticity material model, and it can be multi-linear isotropic model.  See section 7.2.6 for and example here: 

https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v222/en/ans_mat/strmamoco050401.html%23strbischa6801

MIke 

[MLS MLS]

Hello,

I added the plasticity model but my strain is small.

I'm not able to find the example. I just have to copy and past the provided link ?

Thank you.

[mrife]

MLS MLS
Yes if you have access to the Ansys help.  If you have it installed locally then see the MAPDL Material guide in the help.  There is a section on material model combinations (a big list of all the possible combinations).  Each is a link to an example.

[MLS MLS]

Hello,

I used the nonlinear isotropic haredning with the chaboche coefficients but still have the same shape. Anyone have already correlate experimental and simulations hysteresis loop ?

Thanks for Help.