Flex Tire Tab

The Flex Tire tab appears only when a .fxt tire property file is selected. This is an FE based tire model from Pratt Miller (PM-FlexTire) that can be used in co-simulation with EDEM to model tire interaction with soil, sand, gravel, and so on. To use this tire in co-simulation with EDEM, the Pratt Miller tire software is needed which is available as an Altair Partner Product. PM-FlexTire is currently available for Windows only.

Figure 1.

This tab helps to create mesh files (.bdf/.obj/.off) in the required format that the PM-FlexTire uses (Windows only). Refer to the Pratt Miller software user manual for more details. To generate a mesh, a CAD geometry is needed which is referenced in the .fxt file. The .fxt file can also refer to a regular handling tire file that is needed for a static simulation or a transient simulation where the vehicle is traversing on roads not modeled in EDEM.

Once the mesh is created, the AutoTire can be transferred to EDEM through the MotionView-EDEM coupling interface. See the Bulk Material Interaction topic for additional information.

The tab contains the following:
Control Description
Create Mesh Displays the Generate PM-FlexTire files utility to create mesh files for the tire.

Figure 2.
Tire CAD file
CAD geometry file of the tire for meshing. The tire geometry should be positioned such that the tire center is at Global Origin [0,0,0]. Default – refers to the file in the [GEOMETRY] section of .fxt file.
Output file Dir
Directory to output mesh files that is generated. Defaults to the .fxt file location.
PM flextire convertor
Select the STPtoOBJ.exe in the Pratt-Miller software install location.
Controls the coarseness of the mesh.
Tolerance relative to minimum radius (%)
Maps to the “-tol” flag used by STPtoOBJ.exe to identify boundary condition nodes at the minimum radius location.
Belt radius relative to largest radius (%)
Maps to the “-dbelt” parameter used to create the inside elements for carcass definition.
Note: Refer to the PM-FlexTire User Manual for additional details about the -tol and -dbelt parameters.

Upon clicking OK, the mesh files are generated and listed in the panel.

Output file Dir Directory to output mesh files that are generated. Defaults to the .fxt file location. The space below displays the bdf/obj/off files if found in this directory. The file names have to match with the *.fxt file name. There are three off files (*_bead.off, *_belt.off, *_inside.off) necessary to transfer the tire to EDEM. The list is automatically populated after the mesh is generated.
Handling Tire File Handling tire file to be used for initial static as well as transient simulation when the tire is not on the road section represented in EDEM. Default – Handling tire file given in the [HANDLING_PROPERTIES] section in the .fxt file.
Rim Radius

Rim Width

Tire rim radius and rim width of the tire. Defaults to RIM_RADIUS and RIM_WIDTH parameters in the [BEAD] section in the .fxt file. A “Rim” (cylinder) graphic is created for the AutoTire with these dimensions. The Rim graphic is transferred to EDEM to during the transfer process through the coupling interface. The rim radius and width should match with the actual tire geometry such that it closes the tire carcass. Any gap could have a chance of particles filling the inside of the tire during simulation in EDEM.