soil dynamics question

I am currently using abaqus 6.2 to model a soil structure so as to analyse how wave propagates in soil that are caused by vehicles on the road.

Does anyone out there knows how to simulate a viscous boundary so that the waves are absorbed instead of being reflected back at the boundary line?

 

[Ron]

There are a couple of ways to do this...

You may use variable property materials to simulate the viscous condition. Consider a square of Material A having an elastic modulus of X. Surround Material A with a finite layer of Material B having an elastic modulus of some significant amount less than X (this can be varied to simulate the effect...start with X/100). The outer boundary of Material B can be fixed. The constraints between the two different materials can be fixed except in the direction of the needed viscosity.

Another way is to use springs as your boundary constraint and vary the spring constant relative to the stiffness of the material you are restraining.

 

Thanks Ron....but now if i add another new material, wont there be another new boundary to consider now? Is there another way of simulating a viscous boundary using the FEM software abaqus 6.2?

 

if you are in 2D try use infinite element. If you are in 3D you can still use infinite element but ... will need some skill to set it up. Or you can use box-damper.