iMechanica - Ask for a constitutive model for soil with dilantancy and hardening - Comments

Dear Gan

alishafi — Sat, 25 Apr 2009 23:36:57 -0400

Dear gan

Im Ali. I faced your problem as well. The best model for your research is Subloading tij model. also if you want to make a dynamic model using ABAQUS/Explicit, you must use VUMAT interface for producing your model.

With regards

Ali.

Ask for a constitutive model for sand

alishafi — Mon, 20 Apr 2009 06:19:25 -0400

I'm Msc Student of geotechnical engineering. Im looking for an appropriate model for sands in order to produce a dynamic model for sand compaction piles for estimating the effective radius of them. I have read a Modified Druker prager /cap model but its parameters has modified for a special use of dynamic compaction method by considering the depth effects. In my model, because I am using the plane starin condition, the most important thing is which model can consider the cylindrical expansion of sand compaction piles. I have also read the SUBLOADING Tij model. Now I don't know which model is better. Please help me by your precious suggestions.

Dear Gan, Thanks for your

tcnguyen — Fri, 09 Jan 2009 08:21:40 -0500

Dear Gan,

Thanks for your reply with a good idea about using UMAT routine. I still have some problems which I should clarify from the begining:

1) The final goal of my research will be a problem of coupled dynamics-consolidation analysis since I am dealing with a pile load test in saturated sand, I need to know both the stress-strain states of and the pore pressure in the soil mass. And as I understand (maybe I am wrong), there is no commerical software can perform this coupled dynamics-consolidation analysis.

2) Since I also conduct physical modeling, I preferto use a simple constitutive model with not-too-much parameters which can be determined from the conventional laboratory tests and Advanced/Modified Mohr-Coulomb is what I thought about first.

One more time, thanks for your reply.

Chi

User material routine will be a choice

Yixiang Gan — Fri, 09 Jan 2009 05:00:42 -0500

Hi,

From what I have read from your post, I think you only need to change the constitutive model of granular materials. Basically, it does not matter whether you are using commercial or open-source FE codes. You only need to search FE code which provides an interface for user material routine. For instance, ABAQUS has a nice UMAT interface, and also FEAP.

BTW, for representing both dilatancy and hardening behaviours, the modified Drucker-Prager model with Cap will be also an option. Time-depedent behaviour is also available in the model implementation in ABAQUS.

Gan

Ask for a constitutive model for soil with dilantancy and hardening

tcnguyen — Wed, 07 Jan 2009 10:21:39 -0500

Dear researchers,

My name is Chi and I just started my PhD study two months ago. I am experimentally and numerically studying the pore pressure build-up in sands during the pile load test and hence, at the first stage, I need to have a constitutive model for soil with both dilatancy and hardening behaviors.

Due to the practical feasibility, I tend to search or build a model developed from Mohr-Coulomb model for soil with only several parameters which can be determined from the conventionl laboratory tests. I heard about some models as Advanced Mohr-Coulomb or Modified Mohr-Coulomb which exit on some commercial software as PLAXIS, DIANA, ABAQUS... However my final goal will be the coupled dynamics-consolidation problem related to pile load test therefore I wish to have a source code of one model and then developed it further.

If any one of you knows about any open-source code for such a constitutive model (Advanced Mohr-Coloumb for soil with both dilatancy and hardening behaviors), could you please tell mehow/where I can find it?

Thank you so much for your help and your time,

Best regards,

Chi