Simple and Efficient Modelling of Powders with the EDEM Powders Database
Altair EmployeeMaterial model calibration, whereby model parameters are optimised to reproduce a physical measurement, is essential to the generation of fit-for-purpose Discrete Element Method (DEM) models of particulate materials [1]. However, the commonly adopted trial-and-error calibration approach is often time and resource intensive and may require advanced technical expertise. This is particularly true when modelling powders because the calibration of advanced physics models is required to capture their complex mechanical behaviour. These challenges can make the generation of physically accurate powder models difficult and can prevent users from taking full advantage of the benefits that DEM simulation can bring to their powder handling process and equipment design.
EDEM has led the way in resolving the challenges of DEM model calibration and pioneered the material model database approach with the development of the GEMM database. Extensive material model databases such as the GEMM can minimise the challenges and resource requirements of calibration by making thousands of pre-calibrated and physically accurate models directly available to the user. EDEM is now bringing these benefits to the discrete element modelling of powders by releasing the world’s first commercially available powder material model database.
The database contains DEM models that capture the complex bulk behaviour of powder materials while using up-scaled numerical particles to ensure practical solution times when simulating full scale industrial processes [2].
Models that capture the poured bulk density, static angle of repose [3] and steady-state shear stress measurements [4] described in Figure 1 are included in the database. These are common and widely adopted powder characterisation measurements that are easy to perform and ensure that material models relevant for both quasi-static and dynamic flow regime applications are available to the user.
Figure 1 a) Angle of repose test via the lifting cylinder method and b) direct shear test under constant normal stress
A wide range of response values and numerical particle sizes are included in the database (see Table 1), making it applicable to most industrial powder applications. This is achieved by automatically applying well-established particle size and density scaling laws [5] to 4500 simulation datapoints. The result is a comprehensive database with a dense, sometimes fully continuous, coverage of the results ranges that effectively contains an infinite number of models.
Table 1 - Results ranges in the EDEM powders database
Choosing an appropriate model in the database is made easy by the built-in search algorithm, which ranks the models according to the mean relative error between model results and user-defined targets and further refines the output by qualitatively categorizing the models according to their bulk cohesion and compressibility.
The database is fully integrated into the EDEM graphical interface and has the simple and intuitive workflow shown below. Having entered the experimental data and identified the most appropriate material model, all the input properties – from particle size and shape to input parameters for the contact model – are automatically generated in the EDEM pre-processor.
Available with the EDEM 2022.0 release, the new EDEM powders database makes powder modelling simpler, faster and more practical than ever. Whether you are an experienced DEM user, or are brand new to powder simulation, you can now get complex, trustworthy, virtual powder behaviours within seconds!
EDEM for Process Manufacturing
Altair EDEM is a Discrete Element Method (DEM) software that enables engineers to accurately simulate and analyze the behavior of bulk solids, providing key information on processes otherwise difficult or sometimes impossible to measure.
EDEM enables a detailed analysis and visualization of the flow of particles, from powders to tablets, through process segments and handling equipment, and can promote both innovation in product design as well as reducing the need for physical prototypes and long product development cycles.
Watch application examples of powder simulation using Altair EDEM for process manufacturing in the pharmaceutical and additive manufacturing industries.
References
[1] 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
[2] Thakur, S. C., Morrissey, J. P., Sun, J., Chen, J. F., & Ooi, J. Y. (2014). Micromechanical analysis of cohesive granular materials using the discrete element method with an adhesive elasto-plastic contact model. Granular Matter, 16(3), 383–400. https://doi.org/10.1007/s10035-014-0506-4
[3] ASTM D6393 / D6393M-21, Standard Test Method for Bulk Solids Characterization by Carr Indices, ASTM International, West Conshohocken, PA, 2021, www.astm.org
[4] ASTM D6128-16, Standard Test Method for Shear Testing of Bulk Solids Using the Jenike Shear Tester, ASTM International, West Conshohocken, PA, 2016, www.astm.org
[5] Thakur, S. C., Ooi, J. Y., & Ahmadian, H. (2016). Scaling of discrete element model parameters for cohesionless and cohesive solid. Powder Technology, 293, 130–137. https://doi.org/10.1016/j.powtec.2015.05.051