FODDD
Mechanical
- Dec 20, 2013
- 6
Hi,
I'm conducting an axisymmetric deep drawing operation in Abaqus/explicit. I'm using a discrete rigid punch that's flat-ended and I've specified surface-to-surface contact between the punch and blank. The blank is 0.14mm thick meshed with CAX4R elements and is the slave surface, while the punch is the master surface and is meshed sufficiently fine so that it's elements are much smaller than those on the blank.
I wanted to avoid stress singularities at the punch-nose so rounded off the corner instead of using a 90 degree angle. It works fine for a radius above 0.75 mm but below this I'm getting some issues.
In the image attached the deformation is clearly localised and once this begines the max Mises stress does not increase at all, but the PEEQ shoots up (because the elements are elongating so much). I've extrapolated out my plastic data to see would the blank keep deforming with increasing stress and strain but this severe distortion is still happening with a stagnant stress value and an increasing PEEQ value.
a) Just to get things straight, how would I check for stress singularity or how does it show itself?
b) What other factors could be an issue here?
Any help would be greatly appreciated.
Thanks
I'm conducting an axisymmetric deep drawing operation in Abaqus/explicit. I'm using a discrete rigid punch that's flat-ended and I've specified surface-to-surface contact between the punch and blank. The blank is 0.14mm thick meshed with CAX4R elements and is the slave surface, while the punch is the master surface and is meshed sufficiently fine so that it's elements are much smaller than those on the blank.
I wanted to avoid stress singularities at the punch-nose so rounded off the corner instead of using a 90 degree angle. It works fine for a radius above 0.75 mm but below this I'm getting some issues.
In the image attached the deformation is clearly localised and once this begines the max Mises stress does not increase at all, but the PEEQ shoots up (because the elements are elongating so much). I've extrapolated out my plastic data to see would the blank keep deforming with increasing stress and strain but this severe distortion is still happening with a stagnant stress value and an increasing PEEQ value.
a) Just to get things straight, how would I check for stress singularity or how does it show itself?
b) What other factors could be an issue here?
Any help would be greatly appreciated.
Thanks