Systematic design optimization of grabs considering bulk cargo variability

Ship unloader grabs are usually designed using the manufacturer's in-house knowledge based on a traditional physical prototyping approach. The grab performance depends greatly on the properties of the bulk material being handled. By considering the bulk cargo variability in the design process, the grab performance can be improved...

Replicating cohesive and stress-history-dependent behavior of bulk solids: Feasibility and definiteness in DEM calibration procedure

This paper presents a multi-step DEM calibration procedure for cohesive solid materials, incorporating feasibility in finding a non-empty solution space and definiteness in capturing bulk responses independently of calibration targets. Our procedure follows four steps: (I) feasibility; (II) screening of DEM variables; (III) surrogate modeling...

A validated co-simulation of grab and moist iron ore cargo: Replicating the cohesive and stress-history dependent behaviour of bulk solids

The traditional design approach of grabs and other bulk handling equipment consists of manufacturing and testing physical prototypes. A novel design approach is to use a co-simulation of MultiBody Dynamics (MBD) and Discrete Element Method (DEM), in which the virtual prototype of a new concept interacts with bulk solids. Therefore, this study...

Design framework for DEM-supported prototyping of grabs including full-scale validation

The design of machinery for handling granular materials relies mainly on empirical methods and in-house engineering knowledge. This traditional approach provides incremental improvements that are often limited. Advancements in simulation and optimization can offer a promising alternative approach. Most of the research involved in improving or...

Introducing adaptive mechatronic designs in bulk handling industry

The advances of mechatronic system design and system integration have shown improvements in functionality, performance and energy efficiency in many applications across industries, from autonomous ground vehicles and drones to conveyor belts. This trend has been adopted in some industries more than others. The design of equipment to handle...

Bulk properties variability and interdependency determination for cohesive iron ore

An ideal unit of bulk transport or storage equipment is able to handle cohesive iron ore with consistent productivity. In practice, however, uncontrollable bulk property variations affect the productivity. Therefore, it is important to understand the effect of uncontrollable variations on the process. This study quantifies variability and...

A hybrid particle-geometric scaling approach for elasto-plastic adhesive DEM contact models

The computation time of Discrete Element Method (DEM) simulations increases exponentially when particle size is reduced or the number of particles increased. This critical challenge limits the use of DEM simulation for industrial applications, such as powder flow in silos. Scaling techniques can offer a solution to reduce computation time. In...

DEM particle upscaling for large-scale bulk handling equipment and material interaction

Purpose: The development of bulk material handling equipment can be accelerated and made less expensive when testing of virtual prototypes is adopted. However, the modelling of a grab unloader requires a large volume (77 m3) of iron ore pellets, making the computational costs prohibitive. This paper investigates the extent to which the...

A consolidation-penetration test for wedge-shaped penetration tools

Grabs are often used for unloading bulk carriers that deliver iron ore cargoes. The grabbing process starts with cutting the free surface of the bulk iron ore. For that reason, the initial penetration depth of the grabs' knives into the material is an important success factor in their filling ratio. The resistance to penetration is influenced...