From Angle of Repose to Heap Morphology: Full-Field Calibration of DEM for Granular Powders

TL;DR

This paper introduces a novel DEM calibration method using full-field image analysis of heap morphology, providing a more comprehensive alternative to traditional angle of repose-based calibration.

Contribution

It proposes a full-field calibration approach comparing experimental and numerical heap profiles via pixel-wise grayscale analysis, improving accuracy for cohesive powders.

Findings

Full-field heap morphology calibration reduces non-uniqueness in parameter estimation.

The method effectively characterizes heap shape for Ti6Al4V and Al6061 powders.

Traditional AOR-based calibration has limitations in capturing heap morphology.

Abstract

The calibration of discrete element method (DEM) models is commonly performed by tuning model parameters to match an experimental measurements, most commonly the angle of repose (AOR). Although widely used, AOR-based calibration metrics do not adequately characterize the full heap morphology, particularly when dealing with cohesive granular materials. As a result, AOR-based calibrations often leads to non-unique parameter sets. In this work, we propose a DEM calibration procedure based on full-field image analysis of static powder heaps rather than scalar AOR measurements. The method compares an average experimental heap profile (AEHP), obtained from repeated GranuHeap experiments, with an average numerical heap profile (ANHP) generated from DEM simulations. This comparison is performed using pixel-wise grayscale intensity values of both average heap profiles. Two metal powders commonly used in additive manufacturing, Ti6Al4V and Al6061, are used to evaluate the proposed methodology. This work highlights the limitations of traditional AOR-based approaches and demonstrates that full-field heap morphology offers a more reliable framework for DEM calibration.