Modelling a Bulk Solids Mixer Drivetrain with EDEM, MotionSolve, PSIM and Activate

Bulk solids mixing is a fundamental operation in a wide range of industries with continuous mixing gaining popularity due its higher efficiency relative to batch mixing. Ensuring the reliable operation of continuous bulk solids mixers is key but the complex dynamic loading on the mixer drivetrain and the need for uninterrupted operation over long periods of time pose design challenges. At the same time, the traditional design approach, which is heavily reliant on physical prototyping, is time consuming and expensive. Virtual prototyping via a digital twin allows engineers to design faster and at a fraction of the cost.

All requisite files for the example can be downloaded here:

A digital twin of a bulk solids mixer that includes the equipment geometry, electric drivetrain and bulk material can be developed using EDEM, MotionSolve, PSIM and Activate. 

A mixing simulation using the digital twin is shown in the below video and reveals the complex force chains that develop in the bulk solid. An overview of the digital twin components is shown in Figure 1 where:


Figure 1 - Overview of Mixer Digital Twin


The digital twin reveals the complex behaviour of the system that results from the interaction of the electric drivetrain and the particle induced forces on the shaft as shown in Figure 2.

Figure 2 - Complex Dynamic Loading on the Mixer Shaft, the Motor Torque, and Shaft Speed


The set-up in this example is split into five different parts:

  1. 3D modelling the CAD geometry
  2. Modelling the bulk solids material with EDEM
  3. Creating a multibody dynamics model for the mixer shaft with MotionSolve
  4. Modelling the power electronics with PSIM
  5. Coupling all simulation tools together with Activate

1. CAD Modelling

Figure 3 - Mixer Shaft and Shell CAD Model in Inspire

2. EDEM:

To simulate the bulk solid mixing process using EDEM:

Figure 4 - Hopper Geometry Specifications


Figure 5 - Factory Definition for Segregated Particle Generation

3. MotionSolve:

Inside MotionView (MotionSolve’s preprocessor), implement the following steps for the multibody model of the mixer:

Figure 6 - Solver Variables Definition

Figure 7 - Revolute Joint Definition

Figure 8 - Torque, Tx, Definition

Figure 9 - EDEM Subsystem in MotionView

Figure 10 - Enabled EDEM Coupling Server

4. PSIM:

To introduce power electronics simulation and implement control on the mixer shaft rotational speed:

Figure 11 - PSIM Control Loop 


5. Activate:
To connect all simulation tools in Activate:

Figure 12 - MotionView and PSIM Input Settings

Figure 13 - Activate Control Loop

To run the simulation:

Figure 14 - Final Time Settings in Activate

Table 1 - Simulation Timesteps




MotionSolve-EDEM Coupling




A digital twin of a bulk solids mixer that includes the mixer geometry, electric drivetrain and bulk solid can be generated by coupling EDEM, MotionSolve, PSIM and Activate. The digital twin enables rapid virtual prototyping of designs, reducing time and costs.

Further links:

Learn how to optimize the mixer shaft design and operation in this article:

Combining Machine Learning and Simulation for Continuous Mixing Optimization