Nemag and TU Delft design innovative grab for faster unloading

Nemag BV is a manufacturer of grabs designed for handling a range of bulk materials from coal and iron ore to grain, animal feed, scrap metal, minerals or biomass.

Nemag BV has worked with the group of Dr. Dingena Schott at Delft University of Technology (TU Delft) to develop a new generation of grabs for iron ore that are faster and lighter – using EDEM bulk material simulation software to test and optimize the new design.



Grabs are a type of equipment used for unloading dry bulk cargo vessels, grabbing dry bulk material such as iron ore or coal from the vessel and transferring the grabbed material to a hopper on the quay. Development of grabs is still a complicated process as predicting the performance of a new design is hard and involves building physical prototypes – which is expensive, time consuming and limiting; it is hard to understand what happens inside the grab.

The interaction between the bulk material and the grab influences the performance of the grab heavily but it is difficult to predict using traditional methods.

A virtual prototyping approach was therefore developed at TU Delft to model iron ore pellets in interaction with grabs.

EDEM's Role

TU Delft used simulation software to perform virtual testing of a grab design and predict the grab performance.

TU Delft developed a coupling to use EDEM Discrete Element Method with Adams Multi-Body Dynamics software with which they modeled iron ore pellets and a crane in a virtual environment. Extensive model calibration procedures were developed accounting for material structure interaction. With this they were able to capture both material behavior and grab behavior well.

The co-simulation was validated with measurements on industrial scale at Tata Steel IJmuiden in The Netherlands.

The coupled simulation could then be used in the innovative design process providing key insight into the dynamics of the grab together with the iron ore.


Simulation results were used to develop a new generation grab designs.

The patented nemaX® grab combines lower deadweight and higher payloads with shorter closing times, leading to great improvement in efficiency with a vessel that unloads in 10% less time.

In the meantime the new grab has been extensively tested and its performance matches well to the simulation predictions.

The innovative nemaX® won two awards:

  • Innovative Technology Award 2017 by the International Bulk Journal
  • The Red Dot Award 2018

As an early adopter we believed in EDEM to help make a difference in simulation supported design and realize breakthroughs through advanced simulations. We also use EDEM in education; it’s ease of access comes with good support and quick response times.

Dr Dingena Schott, Associate Professor Material Equipment Interaction for Logistics TU Delft

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