PeterMad
Marine/Ocean
- Nov 1, 2011
- 1
Hello everyone,
This is my first post on this forum and I am really hoping that somebody can help me since I am more or less stuck.
Currently I am trying to define the mechanical behaviour, 2D in ANSYS, of a sandwich specimen in 3-point bending (E-glass facing and PVC core).
This particularly concerns the behaviour of the foam material when local indentation occurs.
The model (of the core material) that I am trying to use is based on the polymer foam constitutive model of Deshpande and Fleck. This model is based on the following:
tensile yield of the foam is governed by an elliptical yield surface in von Mises versus mean stress, while in compression the cell walls buckle elastically,
and a maximum principle stress criterion applies (buckling cap in the yield surface).
After studying all the possible non lineair material models in ANSYS I am starting to get convinced that this is impossible with the excisting models.
If this is correct it implies that I have to use the subroutine interface USERMAT.
The quetions:
- Is the assumption correct that there are no models available that can capture the mentioned constitutive model?
- Is it possible to use the usermat3D.F as a base for programming this constitutive model?
If anybody has some thoughts or experience please share.
Peter
ps. if some parts are not clear please let me know
This is my first post on this forum and I am really hoping that somebody can help me since I am more or less stuck.
Currently I am trying to define the mechanical behaviour, 2D in ANSYS, of a sandwich specimen in 3-point bending (E-glass facing and PVC core).
This particularly concerns the behaviour of the foam material when local indentation occurs.
The model (of the core material) that I am trying to use is based on the polymer foam constitutive model of Deshpande and Fleck. This model is based on the following:
tensile yield of the foam is governed by an elliptical yield surface in von Mises versus mean stress, while in compression the cell walls buckle elastically,
and a maximum principle stress criterion applies (buckling cap in the yield surface).
After studying all the possible non lineair material models in ANSYS I am starting to get convinced that this is impossible with the excisting models.
If this is correct it implies that I have to use the subroutine interface USERMAT.
The quetions:
- Is the assumption correct that there are no models available that can capture the mentioned constitutive model?
- Is it possible to use the usermat3D.F as a base for programming this constitutive model?
If anybody has some thoughts or experience please share.
Peter
ps. if some parts are not clear please let me know