In User Tips

Introducing Multi-Mesh

Introducing Multi-Mesh

Sometimes it may be easier to mesh a body with multiple solid geometries in pieces, and then combine the meshes. RecurDyn V9R3 now supports this functionality, known as “Multi-Mesh.”

The following steps explain how to use Multi-Mesh. Below are links to download sample files to follow along:

01_Multi-Mesh_Start.rdyn

02_Multi-Mesh_1st_Meshing.rdyn

03_Multi-Mesh_2nd_Meshing.rdyn

STEP 1: Geometry Preparation

To use Multi-mesh, each pair of geometries in contact must have a coincident curve or line. The procedure below creates a coincident edge curve on each solid body (using the imprinting function).

① Start RecurDyn V9R3.
② Open “01_Multi-Mesh_Start.rdyn”.
③ Change to body edit mode of the body, “Crank”.
④ Click Intersection (Geometry tab, Imprint group, Intersection command).
⑤ Select the FlyWheel solid.
⑥ Select the CrankShaft solid
⑦ Click Exit

STEP 2: Do the 1st Meshing

To use Multi-mesh, each pair of geometries in contact must have a coincident curve or line. The procedure below creates a coincident edge curve on each solid body (using the imprinting function).

① Enter the Meshing Mode for the Crank body.
② Mesh the “Crank” with Solid8 elements. (use 5mm for Min/Max Element size.)
③ Create a PatchSet on the Intersected surface.
④ Click the PatchSet Imprint (Mesher tab, Mesher group, Imp.Patch command)
⑤ Select the “FlyWheel” solid
⑥ Select checkbox in the Sel. column in the 1st row (Crank_FE.SetPatch1)
⑦ Click the Search button, then RecurDyn searches the intersected surfaces on FlyWheel automatically (Face10, Face1, Face2).
⑧ Click the OK button.

※ Note: By Using PatchSet Imprint, RecurDyn Mesher tries to imprint the element information on the Solid, ‘FlyWheel’

STEP 3: Do the 2nd Meshing

① Create the new solid property, “Prop_Solid_1” and the new material property, “Mat_Property_4”
② Mesh “FlyWheel” with Solid8 elements (use 5mm for Min/Max Size.) and use the Prop_Solid_1.
③ You can use the “Display” function to check if the shape of elements for PSolid2 (Property Component) and SetPatch1 are identical.
④ Click Flex Merge (Mesher tab, Mesher group, F.Merge command)
⑤ Select “Topol_1” for Target Topology (the 1st mesh)
⑥ Select checkbox of the Sel. column in the 1st row (Topol_2) of the source Topology.
⑦ Click “OK” button, then RecurDyn Mesher merges the 2 meshes into one mesh.

※ Note: If you DON’T use ‘Flex Merge’, then each mesh is treated as an independent mesh (body)

Multi-Meshing is now complete

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You have likely seen the RecurDyn nonlinear flexible body capability used to simulated the flexible behavior of solid geometry or sheet bodies. Less well known is that RecurDyn’s nonlinear flexible body capability includes the ability to simulate a flexible wire or cable, whether interacting with other rigid or flexible geometry.

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RecurDyn and Particleworks co-simulation: Washing machine

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In another article, we shared a unique application of RecurDyn and Particleworks co-simulation on a clothes styler. In this article we would like to showcase the same type of co-simulation being used to simulate both a top-loading and a front-loading washer. The co-simulation illustrates the dynamic interaction of flexible bodies (representing clothes) and the moving impeller and/or drum in RecurDyn and the fluid particles of Particleworks that represent the water and detergent.

This example demonstrates the power of doing Multiphysics simulations with RecurDyn and partner software. In this case we consider the physics of multibody dynamics, nonlinear flexible bodies, and particle-based fluids. As we provide new combinations of simulation capabilities, the ability to simulate your systems of interest become broader and more accurate.

Some of the critical engineering questions that can be answered with this type of simulation are:

1. How does the motion of the fabric change with different levels of water, quantity of clothes in the drum, or different agitator motion?
2. How does the energy consumption of the washer change with different levels of water or different agitator motion?

Below are two videos showing the co-simulation between RecurDyn and Particleworks with a top-loading washer model and a front-loading washer model.

Top-loading Washer

Front-loading Washer

Other applications of this capability could be:

1. The transport of wet or dry product in flexible containers, including during stacking,
2. Effects of fuel sloshing in flexible containers during vehicle motion,
3. Response of flexible seals in motions to internal and external fluid flows.

Can you think of other examples where an accurate simulation requires the consideration of rigid bodies, nonlinear flexible bodies (with contact), and particle-based fluids?

MotionPort plans to create additional examples of this new capability, both with Particleworks and EDEM. If you have an application of interest, please let us know.  To send your examples, please enter them on our Contact Us page.