Numerical modeling is an important engineering tool for predicting and understanding the behavior of physical systems without the need for experiments. However, numerical models are only useful if they are accurate in their predictions and one of the major challenges that a CAE engineer faces is ensuring the accuracy of their models.
DEM material models prove particularly challenging in this respect, because the physical measurement of the micro-mechanical parameters used to describe the contact forces between bulk solid particles is difficult and often even impossible. This leads to the need for an indirect method of obtaining the appropriate input parameters values. A macro-mechanical calibration approach is typically employed for this purpose. It involves the use of a measurement from a material characterization test as a benchmark for the calibration of the input parameters . Figure 1 illustrates the method.
Figure 1: DEM calibration methodology by the macro-mechanical approach. Images: a), c) and e) from Pantaleev et. al., 2017. Image b) from www.freemantech.co.uk
Although the macro-mechanical approach is the most practical option, it still requires the modeling of the material characterization test, the generation of a large number of DEM simulations with varying input parameters and the subsequent extraction and manipulation of simulation data to obtain the responses of interest.
This is where the EDEM Calibration Kit comes in. It is a collection of EDEM simulations of standard bulk solids characterization instruments and associated EDEMpy post-processing scripts that can be used to automate a large portion of the EDEM material model calibration workflow shown in Figure 2.
Figure 2: EDEM material model calibration workflow
The calibration kit removes the need for modeling standard characterization tests and automates the process of obtaining the relevant simulation data, leading to a significant reduction in the engineering time requirement for the EDEM material model calibration. The included EDEMpy post-processing scripts provide a simple and automated way of generating individual simulation reports, similar to the ones generated by the physical test, as well as a single collated report of key results from all simulation runs. The use of the kit is demonstrated in the following video:
The EDEM Calibration Kit is constantly expanding and the following standard bulk solids characterization tests are currently included:
- Uniaxial Compression Test
- FT4 Powder Rheometer Flow Energy Test
- Schulze RST XS Shear Cell
- Brookfield PFT Shear Cell
- Static Angle of Repose Test
- Rotating Drum Test
- Inclined Plane Test
EDEM users can download the EDEM Calibration Kit from the User Forum.
 Coetzee, C. J. (2017). Review: Calibration of the discrete element method. Powder Technology, 310, 104–142. https://doi.org/10.1016/j.powtec.2017.01.015
 Pantaleev, S., Yordanova, S., Janda, A., Marigo, M., & Ooi, J. Y. (2017). An experimentally validated DEM study of powder mixing in a paddle blade mixer. Powder Technology, 311, 287–302. https://doi.org/10.1016/j.powtec.2016.12.053