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Workshop 08 – Cone Crusher (Breakage)

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OBJECTIVES

The two main purposes of this workshop are to a) learn how to define the mantle and shaft movements required for a Cone Crusher simulation, and b) how to set up breakage parameters. You will learn how to: Define mantle and shaft movements for a cone crusher simulation Set up breakage parameters Tag specific particles and fragments for locations tracking

And you will use these features: Cone Crusher Frame Breakage Histograms User Processes, including: Cylinder Cube Divisions Tagging Particle Calculations

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PREREQUISITES

This workshop assumes that you are already familiar with the Rocky user interface (UI) and with the project workflow. If this is not the case, please refer to Workshop 01 – Transfer Chute for a basic introduction about Rocky usage before beginning this workshop.

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AGENDA

Part 1: Project Setup and Processing Geometry Introduction and Project Creation Project Details and Physics Setup Geometry Import and Inlet Definitions Setting Up, Previewing, and Assigning Cone Crusher Motions

Part 2: Post-Processing Verifying the Particle Size Distribution using a Histogram Using Divisions Tagging to identify where in the hopper a set of fragments originated Accessing the User Manual Conclusion

Materials Definitions and Interactions Particle Groups, Breakage, and Inputs Solver Setup and Processing

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PART 1: PROJECT SETUP AND PROCESSING

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GEOMETRY

(1)

The geometry in this tutorial is composed of: 1) Feed Hopper (Choke Feed)

(5)

2) Housing (2)

3) Transmission Axis 4) 5) Mantle Shaft

(6)

6) Concave (4)

(3)

In the workshop directory the *.stl files can be found.

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PROJECT CREATION Ensure you have downloaded and extracted the WS 08 – Input Files zip folder that was provided along with this PDF. Open Rocky 4. Look for Rocky 4 in Program Menu or use the desktop shortcut. Click on the New Project button, or from the File menu, click New Project (Ctrl+N).

New Project

Save Project

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PROJECT DETAILS The first step of the setup is to define any useful information of the project. From the Data panel, click Study 01 and then enter the information as shown.

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PHYSICS DEFINITION

From the Data panel, select Physics. From the Gravity tab, you can define the gravity components and the time during which it is applied in the project. For this workshop, use all default Physics values.

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GEOMETRY IMPORT

The Geometries step enables you to either create or import geometries. For this case we will import geometry files in *.stl format. Right-click Geometries, point to Import, and then click Custom Geometry.

Select all of the following files:

All parts will be imported using “mm” as Import Unit and with the option Convert Y and Z Axes unchecked. www.rocky-dem .com

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INLET DEFINITION

After the geometries are imported, an inlet must be defined in order to release particles into the domain. From the Data panel, right-click Geometries, point to Create, and then click Inlet.

Under Geometries, select the newly created Inlet . From the Data Editors panel, select the Inlet tab, and then edit the parameters as shown on the next slide.

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INLET DEFINITION

From the Geometry sub-tab, define: Type, Center Coordinates, and Max Radius (as shown). From the Simulation Configuration sub-tab, define: Stop Time (as shown).

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MOTION FRAME

Vertical Axis

Mantle Axis

Pivot Point

Mantle Angle

The Mantle rotates eccentrically around the vertical axis pressing the particles on the Concave, promoting breakage. At the same time, it is free to rotate around the Shaft. The intersection between the Mantle Axis (green) and the Vertical Axis (blue) characterizes the Pivot Point. It is important to have your mantle geometry rotated by the desired Mantle Angle and to know in which direction this is done to properly set up the Cone Crusher movement!

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MOTION FRAME To add motions specific to the cone crusher, from the Data panel right-click Motion Frames, and then select Create Cone Crusher Frame.

A new frame called Cone Crusher 01 appears in the Motion Frames list. To visualize the new created frame, click Motion Frames and then click Preview. A new window will appear showing the geometry and the created frame. You can also adjust the frame size by changing the Default axes size parameter.

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MOTION FRAME – CONE CRUSHER

When the new Cone Crusher 01 frame is selected, the following options are available in the Data Editors panel: Pivot Point: Coordinate of the point around which the Mantle and Shaft will pivot. Rotation Axis: The axis around which the Mantle and Shaft are rotated. Rotational Velocity: The angular velocity along the Rotation Axis. Initial Orientation: The vector about which the Mantle and Shaft begin their rotation. Start/Stop Time: Time in which the motion starts and stops.

The Cone Crusher 01 frame automatically creates two separate motions that are designed to be applied to the appropriate geometries, as follows: Cone Crusher 01 (Mantle) for the Mantle Cone geometry. Cone Crusher 01 (Shaft) for the Mantle Shaft geometry.

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MOTION FRAME

From the Data panel, under Motion Frames, click Cone Crusher 01. From the Data Editors panel, define (as shown): Pivot Point Rotational Velocity Initial Orientation Start Time

Vertical Axis

Mantle Axis

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MOTION FRAME Once the frame has been configured, the motions can then be assigned to their respective geometries. From the Data panel under Geometries, select Mantle Cone and then from the Custom Boundary tab, select Cone Crusher 01 (Mantle) from the Motion Frame drop-down list (as shown). Repeat for the Mantle Shaft geometry, assigning to it the Cone Crusher 01 (Shaft) motion (as shown). At this point, the movement can be previewed using the Motion Preview window. (Tip: Make the geometries transparent to see the motion.) Note: The motion will change when the particles are introduced. The Timestep toolbar (in yellow) is used for the results display. www.rocky-dem .com

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MATERIAL DEFINITION In this workshop two materials will be used: one for all geometry parts (Default Boundary) and other for the particles (Default Particle). Default values will be used for the Default Boundary material (as shown). For Default Particles, clear the Use Bulk Density checkbox and edit the Density value (as shown).

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INTERACTION BETWEEN MATERIALS To set the interaction properties, click Material Interactions in the Data panel.

In this simulation we have two materials, so we need to define two separate interactions using the left and right dropdown lists (shown above): Default Particles x Default Particles Default Particles x Default Boundary

Adjust the parameters for each combination according to the values shown on the next slide.

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INTERACTION BETWEEN MATERIALS

Static Friction: 0.7 Dynamic Friction: 0.7 Coefficient of Restitution: 0.1 Adhesive Distance: 0.0001 Force Fraction: 0

Default Boundary

Static Friction: 0.7 Dynamic Friction: 0.7 Coefficient of Restitution: 0.3 Adhesive Distance: 0.0001 Force Fraction: 0

Default Particles

Default Particles

Note: Particle x Particle interaction values are left default for this workshop.

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PARTICLE GROUP DEFINITION To create a new particle group, right-click Particles in the Data panel and then select Create Particle.

A new particle group is created under Particles. Select the newly created Particle entry to begin editing its parameters.

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PARTICLE GROUP DEFINITION From the Data Editors panel, in the Geometry sub-tab, define Shape Type, Vertical/Horizontal Aspect Ratio and Number of Corners (as shown). To visualize the newly created particle, click Preview. A new Particles Preview window will appear showing the particle geometry.

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PARTICLE GROUP DEFINITION From the Breakage sub-tab, define Enable Breakage, Minimum Size, Reference Size, Minimum Specific Energy, and Selection Function Coefficient (as shown). In the Size Distribution sub-tab, click the green plus button (Add) until you have four size distribution rows. Define Size and Cumulative % (as shown).

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MASS FLOW DEFINITION To create a new particle mass flow, from the Data panel, right-click Input and then select Create Particle Input.

A new entry is created under Input. Select the newly created Particle Input and then from the Data Editors panel, modify the parameters as specified on the following slide.

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MASS FLOW DEFINITION

From the Entry Point drop-down list, select Inlet . Click the green plus button to create an entry row. Select Particle from the drop down list and define the Tonnage (as shown).

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SOLVER DEFINITION From the Data panel, select Solver, and then from the Data Editors panel, select the Solver tab. From the Time Configuration sub-tab, define the calculation Start and Delay times (as shown). In the General Settings sub-tab, select CPU (or GPU/Multi GPU) as Simulation Target, and then set the Number of Processors (or Target GPU(s)). For this workshop, CPU will be fastest due to the low particle count. Click Start Simulation.

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SOLVER DEFINITION

The Simulation Summary dialog appears.

Click OK for Rocky to begin processing the simulation.

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SIMULATION From the Windows menu, click New 3D View. (Tip: To see the particles and motions, make the geometries transparent.) Click the Refresh button (or use the Auto Refresh checkbox) to see the results during processing. The speed of the simulation depends on various factors such as: Number of mesh elements used to define the geometry Number of contacts in the simulation domain at any time Smallest particle size and material stiffness The particle shape and the number of vertices used to define the shape Frequency of file output

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PART 2: POST-PROCESSING

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POST PROCESS – PSD HISTOGRAM Once processing is complete, you can verify that all particles were broken under 0.075 m by using a Particle Size Distribution (PSD) Histogram. From the Data panel right-click Particles, point to Show in new, point to Histogram, and then select Particle Size. From the upper-left corner, click the Configure histogram button and then change the Number of Bins, enable both the Cumulative Bins and Percent Values features, and modify the Limits values (as shown).

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POST PROCESS - DIVISIONS TAGGING

In the last Timestep of the simulation, you can observe that some Particles are accumulating in an open space of the transmission housing (as shown). Using the Divisions Tagging Calculation of the Particles in the hopper, we can identify from what section of the hopper these particles are coming from, which is helpful information for improving the equipment design.

Concerning accumulation www.rocky-dem .com

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POST PROCESS - DIVISIONS TAGGING For this case, a Cylinder will be created at a Timestep far enough into the simulation that the Hopper is full of particles. From the Time toolbar, select the Timestep at 2.0 s. From the Data panel, right-click Particles, point to Processes, and the click Cylinder. From the Data Editors panel, select the Cylinder tab, and then edit the Center and Size coordinates, and adjust the Final Arc Angle value (as shown).

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POST PROCESS - DIVISIONS TAGGING

With the Cylinder set up, right-click Particles, point to Calculations, point to Divisions Tagging, and then click Cylinder . This will generate divisions within the cylinder that was selected.

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POST PROCESS - DIVISIONS TAGGING

From the Data panel, under Particles Calculations, select the new Divisions Tagging (Cylinder )… entry. From the Data Editors panel, select the Tagging tab and then define Domain Range, Initial and Tangential Divisions (as shown). From the Coloring tab, enable Transparency (as shown).

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POST PROCESS - DIVISIONS TAGGING Color Particles using the newly added Property: Divisions Tagging (Cylinder )… From the Data panel, select Particles and then from the Data Editors panel, select the Coloring tab; under Nodes, change the Property to Divisions Tagging (Cylinder )… Tip: Use the eye icon next to Cylinder (under User Processes in the Data panel) to hide the Cylinder coloring and show only the Particles coloring.

Display the final Timestep. You should now see all of the following: Hopper divided in 12 circular sectors. Particles and Fragments colored by the division they started in. The accumulated Fragments colored by their original position in the hopper.

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POST PROCESS - DIVISIONS TAGGING

Lastly, a Cube will be added to separate the accumulated Fragments from the rest of the Particles. From the Data panel, right-click Particles, point to Processes, and then select Cube. From the Data Editors panel, select the Cube tab and then define the coordinates for Center and Magnitude (as shown).

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POST PROCESS - DIVISIONS TAGGING

Another Histogram will be created to show the hopper region from which the accumulated Fragments are originating. With the Cube entry still selected in the Data panel, select the Properties tab in the Data Editors panel, right-click Divisions Tagging (Cylinder )…, point to Histogram, and then click Show in new Histogram. From the upper left corner of the plot window, click the Configure histogram button, and then change the Number of Bins and Limits values (as shown).

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POST PROCESS - DIVISIONS TAGGING From the Histogram, it can be seen that most of the accumulated Fragments are coming from bins 3, 4, and 5 of the hopper. This information may not have been obvious before the Divisions Tagging analysis. Now an appropriate solution can be devised if this particular result is undesirable. (8)

(9)

(10)

(7)

(11)

(6) (12)

(3) (4)

(5)

(5)

(1)

(4) (3)

(2)

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HELP – USER MANUAL

For further information on any topic presented, we suggest searching the User Manual, which provides in-depth descriptions of the tools and parameters. To access it, from the main Toolbar click Help, point to Manuals, and then click User Manual.

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HELP – USER MANUAL In the User Manual, use the Search tab to quickly find the topic you are interested in:

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CONCLUSION

Rocky was used to study the case of a cone crusher. During this workshop, it was possible to: Use the specialized Cone Crusher Frame to easily set up and apply specific mantle and shaft motions. Model Breakage phenomena. Use Histograms to plot PSD and processing results. Track specific particles and fragments through the equipment using Divisions Tagging Particle Calculations.

What’s Next? If you completed this workshop successfully, then you are ready to move on to Workshop 09 – Tablet Coating.

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