Residual stress in 3D models

[MonicaOliveira8949]

Hi,

I am currently working with 3D mesh.

I have been searching the information about the residual stress prediction in 3D models which is a source of shrinkage and wrapage in the part. After searching through this Forum, I had an ideia that CRIMS does not affect the shinkage and consequently residual stress alculation 3D models. The only information I was able to find about 3D shinkage is this:

http://wikihelp.autodesk.com/Simulation_Moldflow_Communicator/enu/2014/Help/0068-User_s_G68/0343-Ana...

Can anybody advise me any literature about how in this case the residual stresses are computed, I mean mathematical formulation. Unfortunatly, I was not able to find it in the Autodesk Simulation Moldflow Help. Thanks in advance for any help and/or advise.

Tatiana

[guischmitd]

Hello, did you find a way of getting the results you needed? or did you change the mesh to dual domain and assumed the incavity residual stress is equal (or equivalent) to the residual stress after molding?

thank you. (btw, português?)

[MonicaOliveira8949]

Hi,

Although for 3D mesh it is not possible to assess directly the residual stress distribution, the results of the complete simulation (filling + packing + warpage) include calculations of material properties and residual stresses in the plastic part. With the aid of the AMI/ABAQUS interface (running a MACRO - mpi2abq.vbs), the finite element model information may be translated from the AMI(r) into a partial ABAQUS(r) input file, also in the process, a number of additional files are generated detaining information about plastic's mechanical properties and state of the residual stresses.
ABAQUS(r) partial input file encloses nodal coordinates, element topology, element properties and boundary conditions sufficient to eliminate the rigid body modes. The residual stress file contains residual stresses description in principal directions associated with that mesh (file with *ist extension).
In order to visualize the magnitude and distribution of the residual stresses, the partial input file must be submitted for analysis in ABAQUS(r)through a command line: "Abaqus job = ?file?.inp interactive". It has to be mentioned that at this stage, the partial input file contains only "general static step", which means that only linear elastic properties of the polymer were used for assessment of the internal residual stresses after ejection of the part from the mould.

Regards,
Tatiana Zhiltsova

[madhukeshwart]

MonicaOliveira,

The residual stress results, you get in abaqus are

are they 'in mold residual stress' or stresses after part ejected from mold ? I mean after warp.....

[rnashwin.kumar]

Hi,

The stresses you get after Abaqus analysis is residual stress and not in mold residual stress.

Inmold residual stress can be seen in Moldflow results directly atleast in DD and Midplane

What abaqus does is, it basically takes these inmold residual stress and relaxes it, this is where you will get residual stresses.

Regards,

Ashwiin