Hello all,
My master thesis is on soil compaction simulation using DEM and for calibration of the contact model, I use Oedometer test. I simulate the Oedometer test and compare it with experimental values. The material properties of the calibrated oedometer simulation is then used in the soil compaction simulation. In Oedometer test, I use particles of radius 1mm. However, to reduce the computation time in soil compaction simulation, I scale the radius of the particles 10 times the original value(i.e. 1cm). Therefore. I should also scale up the material property values. I would like to know whether there are any relationship between the radius of the particle and the material properties like stiffness, friction coefficient etc. Thanks in advance.
Hello,
According to User manual of PFC3D (2005), sphere particle stiffness is related to the radius as follows:
k=4ER, where k= stiffness, E=Young's modulus, R = mean radius of two contacting particles.
Hope this helps.
Thanks for your help. I think this relation can used for upscaling of the parameters.
Hello,
maybe this papers can give you a good help for scaling relations in DEM:
[10] Feng, Y.T.; Han, K.; Owen D.R.J.; Loughran, J.:On upscaling of discrete element models: similarity principles. Eng Comput No. 26(6), 2009
[11] Feng, Y.T.; Han, K.; Owen D.R.J.: Discrete element modelling of large scale particle systems—I: exact scaling laws, In: Computational Particle Mechanics, Volume 1, Issue 2, 2014
[31] Pöschel, T.; Saluea, C.; Schwager, T.: Can we scale granular systems?. In: Sendai, Japan, Balkema, 2001
Your problem is related to term of "coarse graining". In the end it depends on the aim of work, when and how you like to calibrate your systems.
Hi,
In a very simple expression, the stiffness is multiplied in the bond area before bond breakage.