(28d) "Perfect Particles" - 3D Printing of Tuneable Agglomerates for Validation of DEM Breakage Models
3D printing offers the ability to design and produce test agglomerates with controlled properties to replicate simple or complex agglomerate structures, and to use these agglomerates to validate DEM models of agglomerate breakage (Ge et al, Powder Technology 2017). In this work, agglomerates with well-defined structure (tetrahedral and random structures, with varied porosity) and tuneable bond strength properties were designed in CAD and EDEM. A Stratasys Object500 polyjet printer was used to 3D print multiple, identical copies of each agglomerate design, and quasi-static breakage tests were then conducted to vary the strain rate and examine the breakage behaviour. The macroscopic agglomerate breakage experiments were compared with DEM simulations, which used Timoshenko Beam Bond Model (TBBM) contact model recently implemented by Brown et al (Granular Matter, 2014).
Qualitative comparisons of the failure mode between experimental tests and DEM simulations (using TBBM bond model) were successful. The quantitative load-displacement results shown that DEM simulation was an excellent match for the cubic tetrahedral agglomerate structure. However, DEM underestimated compressive loads for spherical random agglomerates. However, the results show that the approach is a significant step forward in the ability to "calibrate" and "validate" DEM models of agglomerate breakage.