# Altair Multi Body Solutions 2021.2 Release Notes

## Highlights

The Multi Body Solutions in HyperWorks v2021.2 release provides several enhancements and bug fixes:
• New MotionView Interface (Beta)
• MotionSolve-Activate-EDEM Co-Simulation
• Bearing Elements
• CM Labs-Vortex Translator
• Multi-Disciplinary Tools Enhancements
• 1D Electronic Stability Program (ESP)
• Vehicle Aerodynamic Forces
• Tire Test Rig
• Vehicle Example Models
• 1D Traction Control Update
• CD Tire Licensing Update
• Other Enhancements
• Resolved Issues

## New MotionView Interface MVX (Beta)

Over the next several releases, MotionView will be transitioning to a new graphical user interface framework and interface. A beta version of the first release of the new interface (MVX) is now available (HyperWorks 2021.2 MV in the Start menu).

For v2021.2, the new interface has been extended with the following features:
• Move Tool for model repositioning.
• Rigid Groups - Group rigid bodies that move together.
• New interactive contexts for Points, Joints, and Markers.
• Show/Hide/Isolate features.
• Ability to change variable names.
• Live animation during Static and Transient solutions with MotionSolve (experimental – use environment variable HW_MV_LIVE_ANIMATION = 1).

MVX supports all existing functionalities that are available in the current interface. Both versions, MVX and MotionView (MotionView 2021.2 from the start menu) co-exist and can be used interchangeably today. However, the new capabilities highlighted above are only available in MVX.

MVX is being released as a beta functionality to solicit early usage and feedback for improvement. The functionality may contain unidentified defects.

## Activate, MotionSolve, and EDEM Co-Simulation

MotionSolve can interface with Altair EDEM, a state-of-the-art bulk material simulation tool. EDEM is based on the Discrete Element Method (DEM) that simulates and analyzes the behavior of bulk materials, such as sand, granules, capsules, grass, rock masses, and so on. In this co-simulation the mechanical part is modeled in MotionSolve and the bulk material is defined in EDEM. MotionSolve is the leading solver.

MotionSolve can also interface with Altair Activate, a solution for creating and simulating multi-disciplinary, dynamic system models. Activate is especially useful for signal-processing and controller design that requires both continuous-time and discrete-time components. In this co-simulation, the mechanical part is again modeled in MotionSolve, but the controller or other signal-processing designs are modeled in Activate. MotionSolve models are added as system block into the Activate model. In this case, Activate is the leading solver.

In this release MotionSolve’s co-simulation capabilities have been expanded such that a MotionSolve and EDEM model can be added as a block into Activate. This allows for a simultaneous dynamic simulation with Activate, MotionSolve, and EDEM, where Activate is the leading solver and MotionSolve is the co-leader to EDEM. This feature is particularly useful for control engineers that are familiar with Activate and are primarily interested in designing and quickly iterating the control part of a system, such as the traction control of vehicle driving on soft soil or the controller for an excavator.

## Bearing Elements

Bearings are involved in almost all mechanisms, such as gearboxes, engines, robotic arms, and so on. In traditional Multibody Dynamics, bearings are often simplified by kinematic constraints, such as revolute of cylindrical joints, or by bushings. To overcome this impediment, MotionSolve was expanded with bearing components designed particularly for system analysis, that is, they were designed to accurately replicate the non-linear compliance of bearings but are simplified enough to accommodate the need for high computational performance. The bearing components require only simple user inputs that can be found in many bearing catalogs. Their results can be used to study bearing loads and their life expectancy. The bearing components are developed on top of the MotionSolve API. They do not exist in MotionView yet. Their support in MotionView will be released in the future.

The bearings library currently supports the four basic types of bearings that are used in most cases: Deep Groove Ball Bearings (DGBBs), Angular Contact Ball Bearings (ACBBs), Cylindrical Roller Bearings (CRBs), and Tapered Roller Bearing (TRBs).

## Activate Contact Iteration (Beta)

MotionSolve allows you to define a 2-D or 3-D contact force between two rigid bodies. Each body is characterized by a set of one or more geometries which can be a 3D mesh, an analytically defined solid, or a 2D curve. Whenever any geometry on the first body penetrates any geometry on the second body, contact normal and frictional forces are generated. In this release, the rigid-to-rigid contact algorithm has been expanded with an “Active Contact Iteration” option that allows penetration to be updated during iteration using the analytical Jacobian. This feature reduces noise in the contact forces.

This feature is optional and can be activated by adding the contact_iteration attribute within the command statement Param_Simulation in the XML input file (see the example below). This feature is not available in MotionView yet.
<Param_Simulation

contact_iteration = {"ACTIVE | INACTIVE”}

/>

This feature is being released as a beta functionality to solicit early usage and feedback for improvement. The functionality may contain unidentified defects.

## Translator to Vortex-Studio

Vortex-Studio is a real-time simulation and visualization software by CM-Labs, an APA partner. A MotionView to Vortex-Studio translator is now available. Using the translator, a MotionView model can be translated to Vortex-Studio to simulate and visualize a proven multi-body system in real time for human-in-loop testing and immersive training. (https://www.altair.com/resource/introduction-to-vortex%C2%AE-studio-by-cm-labs-simulations)

Translation supports transfer of commonly used entities in MotionView such as Bodies, Rigid Joints, Joints, Linear Motions, and Bushings.
Bodies Rigid body only. Flex body and NLFE body is not supported.
Graphics CurveGraphics, Outline, Spring, Tire graphics are not supported.
Joints CV Joint, Screw Joint are not supported.
Motion Linear only. Curves, Spline3D, and Expressions not supported.
SpringDampers Linear only. Curves, Spline3D, and Expressions not supported.
Bushings Linear only. Curves, Spline3D, and Expressions not supported.
Forces Linear only. Curves, Spline3D, and Expressions not supported.
Contacts Only a collision rule is defined in vortex. No other contact properties are translated.

To use the translator, load the preference file (File > Load > Preference File) CM Labs Vortex Studio Tools that will add a Vortex menu. The menu contains a Settings dialog that will help to associate Joystick actions to motions in the model and cameras on bodies.

## Multi-Disciplinary Tools Enhancements

• New paired versions of actuation features are introduced; namely twinrod, twinstrut, and twinactuator.
• New attachment feature "rod2cylinder" is introduced to define a rod to cylinder connection made of two equivalent cylindrical joints with friction based on deformable curves.
• Improvements in existing rod, strut, and actuator features to align their behavior with the new paired versions of actuation.
• Improvements in cable feature and all related cable demo models.
• A bug related to units' management has been fixed in "road4durability" feature of Automotive.
• Loading of Compose feature (Plot FRF) for MotionSolve in Activate has been automated.
• Improved solids2motion and meshes2motion features to support meta characters in component names.

## 1D Electronic Stability Program (ESP)

MotionView adds a new 1D Electronic Stability Program (ESP) controller for the Car/Small truck library. The ESP is a driver assist system that improves the vehicle’s stability through intervention in the braking system. By individual wheel braking ESP can control the yaw moment of the vehicle, thus its steering behavior.

To use the ESP controller, select the Electronic Stability Program (ESP) (with ABS) option in the ABS, ESP and TC for Full vehicle with Driver model menu while assembling your full car in the Assembly Wizard.
In the ESP configuration, the braking system is modeled in MotionView while ESP ECU, ABS ECU, and Hydraulic Modulator are modelled in Altair Activate and exported as an FMU. The schematic below illustrates the interaction of the ESP system with the vehicle model.

## Aerodynamic Forces in Vehicle Models

MotionView adds the option to include Aerodynamic Forces in full vehicle models. The option is available in the Car/Small truck library in the Assembly Wizard.

The aerodynamic parameters are entered in a TeimOrbit property file .aae including Environment parameter; Wind velocity; Side Forces; Drag, Lift, Yaw and Roll coefficients.

The vehicle models in MotionView uses by default the -X as forward direction and -Y as left direction. In previous release the Altair Driver only accepted the default vehicle modeling coordinate system to simulate the events.

In this release, by specifying the Vehicle Orientation in the AltairDriver panel, the model can be simulated in any coordinate system. You need to provide the “Front” and “Left” directions of the vehicle to the Driver by specifying this in the user interface panel.

## N-Post Shaker

The N-post Shaker can now be used to simulate event with vehicles in any coordinate system. In previous release, as for the Altair Driver, the vehicle could only have -X as forward direction and -Y as left direction.

In the N-post panel, now you will see the vehicle orientation option to enable different coordinate system setup. You need to provide the “Front” and “Left” directions of the vehicle to the event by specifying this in the user interface panel. Upon adding a new n-Post event, these directions are copied from the AltairDriver set-up. However, if this is changed in the Driver user interface panel after loading the n-Post event, you need to repeat the same change in the existing n-Post event’s panel as well.

## Tire Test Rig

MotionView adds a new Tire Test Rig to enable you to test the tires under various conditions of Lateral slip, Longitudinal slip and vertical loads.
The tire test rig can be added in the Assembly Wizard of Car/Small Truck. The events are added using the Task Wizard.
In the three events available (Lateral slip, Longitudinal slip, and vertical loads), a combination of Loads, Slip angles, and Camber angles enables you to capture the main tire outputs with variable conditions. The events contain a Report to quickly visualize the results.

## New Vehicle Example Models

Two new examples have been added under the Example models:
• Electric Sport Bike: A motorcycle model parametrized to enable AltairDriver at any coordinate system, including an electrical powertrain.
• Pickup Truck: A 4x4 vehicle with an IC engine and ABS control model.
In addition to the new examples, the 3-wheeler models (Auto Rickshaw, Three Wheeler (2+1), and Three Wheeler (1+2)) were updated to include better suspension parameters and graphics.

## 1D Traction Control Update

In the 1D Traction Control, FWD and RWD had to be specified in the 1D Activate model before exporting the FMU. In this release a switch was added in the Traction Control system in MotionView. By selecting FWD or RWD vehicle Traction, the controller is defined automatically to the desired setting. If the drive axles is switched after creating the model, then the proper value for traction control needs to be set inside the traction control Forms.

Traction Control for 4WD/AWD vehicles is not available in this release. This option will be considered for future releases.
Known Issue
Traction Controller does not work for 4WD/AWD configuration vehicles. The option to add Traction Controller for such vehicles has been withdrawn.

## CD Tire Licensing Update

CD-tire files can be used with Altair MotionSolve either by enabling the CD-Tire licensing with Altair licensing or using the CD-Tire standalone license.

With an Environment Variable you can now specify which license MotionSolve checks first.
Altair license file will be checked for CDTire license. If it fails, Flexlm licensing will be checked for CDTire’s own license.
Flexlm licensing will be checked. If it fails, MotionSolve will exit the simulation.

## Other Enhancements

• The new SpringDamper graphic has options to control the display of the spring and the damper.
• Graphics has a new attribute “hide_in_post” to avoid writing the graphics into MotionSolve result h3d after the simulation.
• Validity checks are now performed for properties of Beams and Polybeams.
• Datasets attributes are now available for edit in Data Summary.
• FlexTire file created during transfer of AutoTire to EDEM has been updated as per latest form prescribed by Pratt-Miller/FlexTire.
• The “Auto color” option in View Reports has been changed to “Use report colors”. Turning this option on uses the color specified in the report template while generating plots. The default is set to off since it is desirable to have unique colors for curves when overlaying results.

## Resolved Issues

• Spring graphics from older versions were hidden when the model was read in v2021.1.
• Certain models took multiple clicks on “Fit” (the “f” key) to fit the model.
• Certain specific models with CAD graphics built in v2019 had their components mismatched with bodies when reading in v2020 and later.
• File for user defined spline not written to MotionSolve Py.
• Export to Py fails when model contains user defined Modal Force.
• Load Export: Opening Meta file on runs with Polybeam results in an error.
• Load Export: Incorrect tabulation of force values when multiple outputs are requested with different reference frame.
• Load Export: Missing output when multiple outputs are defined on same body.
• FMU: FMU panel did not identify the correct number of states.
• FMU: Parametric expressions in FMU parameters are not correctly evaluated during export to MotionSolve.
• Memory related application error is fixed for “Generate H3D from EDEM” tool. The tool now gives appropriate message if memory is insufficient.
• Application error during copy operation in model containing components with special characters.
• MotionView crash with model containing AutoDriver during export to MotionSolve when path exceeds a certain limit.
• Nodes dialog is not active on flexible body panel in Abaqus solver mode.
• Using interactive HyperMesh in Import CAD/FE using HyperMesh gives an application error.
• Autotires supports now different Point Cloud Data (PCD) roads for each individual tires.
• The friction transition velocity in the LeafSpring Builder has now better default values.
• CD-Tire representing the rigid tire when using with PM-Flextire and EDEM was showing wrong error message.
• If not specified a handling tire in the PM-Flextire, MotionView adds a default tire and issues are no longer displayed.
• Setting Initial Conditions for vehicle models enhanced to support the AltairDriver in any coordinate system.
• Updated B123 that resolves some issues at singularities (~90 degree).
• Memory management during solution for models including NLFE components has been improved.
• If a body had a large initial rotation, then the system was not assembling to the correct configuration.
• Kinetic energy is now reported in model units to be consistent with other results.
• OML support not available on Linux with Compose v2021.1. You should use Compose v2021 instead.