matonking
Mechanical
- Nov 4, 2013
- 5
Hey guys,
I'm really running out of time with a course assignment and I need help setting up the model itself as I have no idea if it's even working as it should. Model is attached.
Model description:
Sheet of rubber 0.1m^2 and 0.01m thick is subjected to a uni-axial stretch ratio of lambda=2. Make use of symmetry to model just 1/8th of the sheet with 10x10x1 continuum elements. Model material with E=3MPa and v=0.49.
From there a series of progressive modifications are to be made to include NGLEOM and ODGEN which I can do pretty easily.
My issues:
Symmetry: What planes of symmetry should I use? I've currently modelled it as the sheet cut into 4 and then thickness halved.
Boundary conditions: What boundary conditions should I apply to ensure no rigid body motion, symmetry constraints satisfied WHILE allowing a displacement loading condition to create the stretch ratio?
My model:
I've modelled it as sheet cut into 4 and the thickness halved. I've applied symmetry boundary constraints that I would normally apply for beam deformation problems but as this is rubber I have no idea if they are appropriate. The model seems to run fine until I put NGLEOM on at which point it aborts. The deformation looks pretty bad too.
Any tips, pointers or solutions would be extremely helpful.
Thank you.
I'm really running out of time with a course assignment and I need help setting up the model itself as I have no idea if it's even working as it should. Model is attached.
Model description:
Sheet of rubber 0.1m^2 and 0.01m thick is subjected to a uni-axial stretch ratio of lambda=2. Make use of symmetry to model just 1/8th of the sheet with 10x10x1 continuum elements. Model material with E=3MPa and v=0.49.
From there a series of progressive modifications are to be made to include NGLEOM and ODGEN which I can do pretty easily.
My issues:
Symmetry: What planes of symmetry should I use? I've currently modelled it as the sheet cut into 4 and then thickness halved.
Boundary conditions: What boundary conditions should I apply to ensure no rigid body motion, symmetry constraints satisfied WHILE allowing a displacement loading condition to create the stretch ratio?
My model:
I've modelled it as sheet cut into 4 and the thickness halved. I've applied symmetry boundary constraints that I would normally apply for beam deformation problems but as this is rubber I have no idea if they are appropriate. The model seems to run fine until I put NGLEOM on at which point it aborts. The deformation looks pretty bad too.
Any tips, pointers or solutions would be extremely helpful.
Thank you.