Pressure Load not following Amplitude Curve

[redgirl]

I am using a pressure load to expand a stent. The pressure load follows a smooth step amplitude curve that increases to a maximum pressure then decreases to zero. I expect recoil of the stent once the pressure amplitude curve begins to decrease. The problem I am having is that the stent is continuing to expand after the maximum is specified.

I am using Abaqus/Explicit. I have changing the density to a much lower value to lower the overall mass in the system. The kinetic energy is remaining below 5% of the internal energy of the system. I have also tried increasing the overall step time and I have tried an amplitude curve that holds the pressure constant before it begins to decrease but all to no avail.

If anyone has come across anything similar and has a fix I would really appreciate it.

Thanks!

 

[Dave442]

Hi redgirl,

I have performed a similar sort of analysis before and did not experience this problem. Are you 100% positive that your amplitude is configured properly and the energy balance is OK? How exactly have you configured the pressure time-wise?

As an alternative you could create a rigid cylinder and drive the expansion of the stent using prescribed displacements and contact.
There is a benchmark analysis for this type of job on the Simulia website at this URL (scroll down to job S5):

http://www.simulia.com/support/v67/v67_performance.html

You can contact Simulia to get a copy of the input file for the analysis. Or if you prefer, you could post more details and/or your input/database file and I might be able to help you a bit better?

Hope this helps,
Dave