Material model calibration techniques in EDEM – Altair EDEM

Material model calibration techniques in EDEM – Altair EDEM

Discrete element simulations are dictated by the bulk material model, particle geometry, and the contact models used in the simulation pre-processing stage. Within Altair EDEM we start by defining the bulk material properties and contact models. These can be determined using manual calibration, the GEMM database, EDEM Soils Starter Pack, EDEM Calibration Kit, and EDEM Cal.

When performing manual calibration of an EDEM material model assume values for the unknowns for simulations involving the angle of repose test. Next calibrate the current bulk material properties to match the results obtained from a real-world angle of repose test, for example, until the virtually obtained simulation parameters correlate to reality.

The Generic EDEM Material Model (GEMM) Database refers to a collection of material properties for a variety of real-world materials. A graphical user interface prompts a user to select options that relate to the material that they are interested in simulating for their process. Each prompt limits the options internally selected by the search algorithm. The final screen displays a list of possible material property values that a user can select based on their previous prompts.

Users that work with soil have the option to use the EDEM Soils Starter Pack that assist users in selecting the appropriate contact models for the sample of soil that they are interested in simulating. Recommendations are provided based on the users understanding of the bulk cohesion (how sticky the soil is) and the compressibility of the soil.

The EDEM Calibration Kit refers to a collection of pre-defined EDEM models that depict bulk solid characterization instruments as well as a EDEM Python post-processing script. These characterization tests assist users in streamlining the workflow associated with obtaining simulation parameters and decrease the time it typically takes users to define the EDEM material models.

EDEM Cal is an automated tool that determines the effect of various simulation input parameters on a simulation by running multiple simulations and extracting the data of interest. After constructing a base simulation, users can utilize EDEM Cal to define which simulation parameters should be varied to investigate their effects.

EDEM Calibiration Kit
Figure 1: Graphical representation of the workflow used by the EDEM Calibration Kit in Altair EDEM.
Consider Figure 1, calibration of material models is generally associated with an iterative process. During each calibration iteration, simulation input parameters are defined, simulations are performed, and simulation solution data is extracted. The solution data is then compared to known experimental data. If any differences are observed in the simulation data compared to the experimental data, then slight changes are made to the input parameters until the simulation-based solution converges to the experimental data.

Altair EDEM is optimized to assist users in defining bulk material properties and related contact models when considering cohesive materials. Users are, however, not limited to only using these calibration functionality tools as they exist when material parameters are unknown or difficult to determine.