Linear variation of material properties with depth

harryvanlangen

I would like to model a foundation problem with linear increase of stiffness and strength over depth. Is it possible to enter this or can I modify the input file with (say) Python to achieve this?

JohnM

Run a dummy thermal through the depth of your foundation, so that your temperature is run from let's say 0-1C. Transfer this temperature field to your structural analysis, then use a temperature dependent E with the desired variation. Make sure you do not have thermal expansion effects turned on - if you need this, you'll have to be careful about how you choose your numbers.

harryvanlangen

Thanks I will give that a try.

DaveStupple

JohnM, would the dummy thermal be run as thermal steady state using the internal solver? After this, transfer temperatures from solution to create a set of node temperatures. How to go from here to temperature dependent E? Do we need to switch to Static 3D analysis? Thanks

Victor

Either solver would do for the thermal solve. Then yes, switch to Static 3D or any mechanical analysis type that allows thermal stress. That will have to be CCX though. Define the temperature dependent Young's modulus using CCX cards.

JohnM

Thanks for catching that one Victor!
Take a look at your *.inp file, cut and paste the *MATERIAL cards down to the first *SOLID card, and put into the "custom model definition" option in the CCX tree. Use the "Don't generate" option to suppress the writing of the necessary commands. Then look up *ELASTIC in the CCX manual to see for format for temperature dependent properties - it's straightforward.

DaveStupple

Victor & JohnM, thanks for that.