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Breaking barriers: using Rocky DEM to simulate and optimize a combine harvester

Our Breaking Barriers with Rocky DEM series shows new ways Rocky can help engineers and designers solve industrial problems. In this blog post, we explain how Rocky can simulate each step in a real-scale combine harvester’s process while considering millions of flexible particles. Read on to find out how the tool modeled a combine harvester to predict and compare operating and design conditions in order to improve the equipment’s performance.

To optimize the performance of equipment such as a combine harvester, engineers must consider multiple factors and conditions: the ability to model the crops, the flexible nature of the crop, the large number of particles modeled as fibers, the cutting of crop, and the multiple parts of the combine, which are also in constant motion.

Agricultural crops such as wheat are flexible, making it challenging to predict their behavior. To gain real insight into the behavior of these types of particles, Rocky DEM flexible fibers can be customized for each type of grain or other product, allowing designers to model many different kinds of agricultural crops and processes. 

Modelling different kinds of crops

In this example, custom fibers were used to model the reel fingers on the combine, and flexible fibers were used to model the crops, as illustrated below in Figure 1. Flexible particle capability is unique to Rocky. 

combine harvester fiber customization
Figure 1: Rocky DEM’s flexible and custom fibers used in modeling a combine and a crop.

Rocky can even model a crop as flexible fibers that are allowed to break, and a fiber can be set up to have multiple elements. In the example below, the fiber is composed of twelve elements, with one frozen element attached to the ground and translated at the combine speed while the combine remains static (see Figure 2.)

rocky dem fiber customization combine harvester
Figure 2: Rocky’s fibers can be customized in multiple ways. 

In this simulation, API custom inlets were used to produce realistic field patterns by randomly positioning the fibers as seen in Figure 3. 

combine harvester simulation rocky dem
Figure 3: Rocky DEM can create a realistic pattern for crop behavior.

Predicting operating and design conditions for a combine harvester

Rocky accurately models all moving parts via its embedded motion capability, so no external software is needed. Inside Rocky, only the relevant geometries are enabled during the simulation; the remaining geometries are there for post-processing, but they aren’t active during the simulation. In this case, the cutting of the crops is modeled easily and accurately (Figure 4).

combine harvester design
Figure 4: Flexible fibers being cut are modeled accurately in Rocky.

In the past, these applications used to be scaled down (simplified), but with multi-GPU capability, Rocky gives engineers the ability to include millions of particles in their DEM simulation and help develop a more realistic simulation of a real-scale problem. 

Because conditions (e.g. weather), and design demands (e.g. speed) can change, different operating and design conditions need to be analyzed and compared. In this example, Rocky provided accurate measurement of the total throughput, which, compared with the total harvested area, shows the combine harvester performance. Engineers learned through this simulation that even though a faster combine harvested the field more quickly, the slower one delivered more cut crops per acre, ultimately boosting production and profit. Watch our combine harvester simulation video below to see this example in action.

In the dedicated section of our YouTube Channel you can check out more examples of how simulation can help you with other types of agriculture equipment, such as tractors, hay balers, and silos.

Rocky DEM can help agricultural companies solve many different problems, such as reducing grain damage during harvesting, improving corn stover biofuel production efficiency, and accelerating equipment process development.

Contact us today to see how Rocky can improve your agricultural processes and equipment design.


Vinicius Daroz

CFD-DEM Applications Engineer, ESSS

Vinicius Daroz earned his BS in Mechanical Engineering and an MSc in Engineering Turbulence from the Post-Graduate Program of Mechanical and Materials Engineering (PPGEM) at Federal University of Technology, Paraná (UTFPR). He is currently working at ESSS as a CFD-DEM Applications Engineer on the Rocky DEM technical team. Before joining ESSS, Vinicius was a researcher at the Center of Research on Rheology and Non-Newtonian Fluids (CERNN), working with the Oil & Gas industry to study the transport of solids in turbulent flows.


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