Underground Tank Simulation

[Usberti]

Hi,

I need to do a simulation with Creo Simulate 10.0.3 as indicated in the subject.

I used shell finite elements ans it is not a problem to set constraints and the internal idrostatic pressure, the problem is another 

The tank is covered by sand, 30 cm per side as indicated in the attached files. The sand causes a force on the tank, and limits the lateral expansion. How can I interpret the sand? With a Force/Pressure on the tank and a laterally Pressure/Constraint/Springs to limit the lateral expansion? In order to represent the sand I also thought to create an external component/body but I think it is too complicated. I'll need sand structural property and I'll have to decide if use bounded interface or contact interface between tank and sand.

Any  suggestion?

Thanks

[SweetPeasHub · Accepted solution]

Modelling soil mechanics is an advanced subject and Creo simulation is likely not chosen for such simulations. There may not be anyone in the community with experience modelling sand. What is the purpose of the sand? To allow a weaker pressure vessel? Insulation? Safety? Depending on the sand I can see there might be a discontinuity causing a stress increase at the transition from sand to no-sand. As a first look I might model the sand as 3d like you say, with a bonded interface and then vary the sand stiffness value from very low to very high and making myself satisfied of the design no matter whether the sand is absent or it hardens into concrete. I would probably consider adding a hydrostatic load based on the mass and depth of the sand as well, as if it was liquid. Just thoughts... Good luck.

[Usberti]

Thanks!

[skunks]

I would have suggested the following steps:
Do not use shells, as the shells in Creo Simulate are always linear.
I would simplify the container as much as possible (a quarter?).
There are NO fixed constraints here, only surrounding volume.
The bottom has contact condition to the container.
Surrounding sand has composite contact, with corresponding properties: I would set the transverse strain coefficient to 0.499 (incompressible).
E-modulus very small...

[skunks]

example

[Usberti]

Thanks