What's new in LMS Virtual.Lab Rev 7

LMS Virtual.Lab Motion Rev 7 strengthens simulation capability for vehicle handling and ride comfort

LMS Virtual.Lab Motion offers dedicated solutions to simulate the ride and handling behavior of vehicles from passenger cars, to motor sports vehicles and up to multi-axle commercial vehicles such as trucks and buses. With Rev 7, LMS Virtual.Lab Motion gains important new capabilities to simulate vehicle and driver interaction, to accelerate the creation of full-vehicle models and to smoothen the exchange of these models with other development departments.

Accounting for the human factor

To further step up the accuracy and reliability of vehicle handling and ride-comfort simulation, LMS Virtual.Lab Motion incorporates the complex interaction between driver and vehicle. LMS integrated the industry-standard driver model developed by IPG Automotive in Germany. The IPG-DRIVER model adds actions and re-actions of a human driver to the dynamic model of a vehicle. By calculating vehicle model inputs that result from human actions - including gas, brake or clutch operation, gear shift and steering - IPG-DRIVER is able to realistically model different driving styles, from defensive to aggressive. Through the integration of IPG-DRIVER in LMS Virtual.lab Motion, ride and handling engineers can simulate closed-loop maneuvers, while taking human behavior and response into account. This approach allows them to simulate all chassis, driveline and control system parameters (ESP, ABS, etc.), and tune and validate them early in the design process. This was previously only feasible with physical prototypes and human drivers.

Realistic full-vehicle simulation

LMS Virtual.Lab Motion Rev 7 introduces new tools to drastically accelerate the vehicle modeling process and to make the process error-free. Virtual.Lab Motion offers a set of predefined parameterized suspension designs, including double A-arm, McPherson, multilink and quadralink systems.

In addition to detailed chassis modeling, real-life vehicle simulation requires accurate representations of a number of complex vehicle subsystems, such as steering, braking and driveline system. Specifically for these subsystems,

LMS Virtual.Lab Motion Rev 7 offers dedicated parametrized models, for which it automatically integrates all relevant points, parts and connections into the vehicle model. For example, after integrating a driver model along with steering/braking/driveline capability, the forces applied to the braking paddle are converted dynamically into corresponding brake torques on all four wheels.

Christophe Chanteur, who works at the CAE Full-Vehicle Department at PSA PEUGEOT-CITROËN in France, confirms that this way of working offers great benefits. “The newly introduced modular approach for full-vehicle modeling matches our needs and is very useful to us,” Christophe Chanteur stated. “It enables us to create full-vehicle models starting from the models of their submechanisms, and also to define standard driving maneuvers much faster than before.”

Event-specific vehicle performance

LMS Virtual.Lab Motion Rev 7 features an extensive library of predefined vehicle events that include both open-loop and closed-loop vehicle maneuvers, such as slow ramp steer, ISO lane change and constant radius/speed cornering. Besides the availability of a long list of pre-defined vehicle events, the flexibility is offered to specify any kind of user-definable event. All it takes to set up a simulation that includes multiple runs of standardized events is selecting the events that are required, instead of tediously defining control elements manually. To efficiently validate the suspension design, automotive engineers benefit from LMS Virtual.LabÌs automatically processed suspension-related graphics, which include Ackerman error charts, anti dive/lift graphs and dependent suspension plots.

Higher simulation consistency between ride and handling and NVH

To guarantee consistent model data across vehicle performance attributes, MBS-to-FEA model conversion supports synchronization of different virtual prototype modelsÒ multibody models used for ride and handling and finite-element models developed in NVH departments. Multibody models are solved as time-domain results, but converting them to NVH models allows the data to be used for frequency-domain results as well. All parts, hard points, joints and bushings are automatically translated from a multibody to a finite-element representation. Joints are converted to triads at corresponding locations and coupling equations between nodal degrees of freedom. Bushings are converted into spring elements, while flexible bodies are copied directly to their appropriate positions in the NVH model. Design tables that include model parameters ensure proper synchronization of vehicle parameters in both model representations. The smooth MBS-to-FEA model conversion enable development teams to secure consistent model data across different attributes throughout the detailed engineering process.

Simulation at the race track

Developed in cooperation with leading NASCAR series racing teams, LMS Virtual.Lab Motion features a dedicated simulation solution for professional racing teams.

This solution gives them immediate access to sophisticated racing car simulation capabilities, avoiding modeling errors and saving valuable time. Based on straightforward entry of relevant vehicle parameters, the user is guided through a very effective process that covers vehicle assembly, dynamic simulation and result documentation.

LMS Virtual.Lab Motion executes a wide variety of automated analyses in the background, including steady-state cornering, dynamic maneuvers, 7-poster rig tests or Kinematics and Compliance rig tests. Racing team professionals appreciate the simplicity of the user interface and the efficiency of the simulation solution, which allows them to run full-vehicle studies at the race track during testing and racing.

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LMS Virtual.Lab Motion Rev 7 raises the bar in productivity and precision

The most challenging task for engineers is to guarantee that the dynamic performance of complex mechanical systems will match specifications. They need to make sure that the numerous components interact and move as planned under the influence of real-life conditions, such as applied loads, gravity, and frictional forces. LMS Virtual.Lab Motion Rev 7 adds an impressive series of enhancements, new solver technology, and modules to increase the efficiency and the precision of realistic motion simulation to tackle these challenges.

Superior flexible body modeling and processing

Many light-weight assemblies - such as a sun roof of a car or a flap mechanism on an aircraft wing - rely on the precision and reliability of sliders and rollers, even if components face considerable deformation under operational loads. The new Flex-to-flex Surface Contact tool in Virtual.Lab Motion helps addressing this challenge. As an addition to the existing rigid contact module, it is developed to take into account the flexible deformation of two components that touch one another during motion. Flex-to-flex surface contact provides higher prediction accuracy of mechanism motion and the resulting internal forces.

The additional processing effort required for modeling flexible bodies may become too lengthy when dealing with large FE models. The ERFEM (Experiemental or Reduced Finite Element Modes) technology integrated into LMS Virtual.Lab Motion Rev 7 utilizes proven and accurate methods to reduce large FE data sets. It offers the ability to use experimental modes or to create a dramatically reduced modal model. Data reduction is achieved by using a subset of nodes/elements, simplifying mass definition, and applying a wireframe representation to connect the subset of nodes. ERFEM technology enables automotive engineers to set up a full-vehicle multibody model directly on the basis of a detailed vehicle body FE model, without requiring mesh coarsening. LMS Virtual.Lab Motion additionally supports the direct use of FE models created in ABAQUS

Quickly swapping parts in assembly models

LMS Virtual.Lab Motion Rev 7 fully supports the CATIA V5 Publications, which strongly enhances its CAD associativity. This capability enables users to assemble and solve complete mechanisms using simple wire model representations of parts that are not yet available as CAD parts, for example in the early design process. When missing CAD parts become available, they can be easily swapped with their wire model counterparts, without having to redefine all joints and forces attached to parts being replaced. Users can immediately rerun a simulation, without wasting valuable time in splitting and rebuilding the validated system model. In addition to supporting CATIA Publications, Virtual.Lab extends its openness to multiple CAD environments. LMS Virtual.Lab Motion Rev 7 also enhanced its import capability of Pro/Engineer CAD models, and native import for Unigraphics version 11.

Innovative solver technologies tackle tough motion challenges

Gear and chain simulation tends to suffer from long run times because of the vast number of dynamic contacts between all subassembly segments. Dynamic motion simulation requires a significant calculation effort for the inter-component contacts, which needs to be repeated for each simulation time step.

Instead of searching for colliding pairs between body segments, LMS Virtual.Lab Motion’s new contact search algorithm pre-processes the shape of colliding bodies in order to predict contact regions for the next time step.

Focusing search operation solely on these limited regions reduces simulation processing time 100% and more when tackling representative benchmark models. In general, continuous investments in solver technology yield considerable CPU time improvements, as LMS Virtual.Lab Rev 7 performed motion simulation of a representative industrial engine chain model twice as fast!

Improved efficiency - shorter learning curve

To accelerate the modeling and simulation workflow, the number of icons and dialog menus in LMS Virtual.Lab Motion has been optimized. The time required to load documents, synchronize tables and switch workbenches has been drastically shortened. In addition, the smoothness and speed of animations have been further tuned. LMS Virtual.Lab Motion Rev 7 offers improved handling of large FE data sets for flexible body representations to speed up post-processing and animation of results data.

Higher track simulation efficiency

For agricultural or construction vehicles that use tracks LMS Virtual.Lab Motion Rev 7 has lined up a series of enhancements for higher modeling and simulation efficiency. The software now supports the BDF implicit integrator when a track super-element is part of the model. This results in faster simulation when the model includes highly damped degrees of freedom. For discrete track models with many bodies, joints, and contact force elements changes implemented in contact-oriented search logic further increase the efficiency. To avoid verification of distant contacts, the search process is restricted to bodies that make contact with the sprocket. Another modification limits the search for ground contact, which now excludes contact verification for regions of the ground profile that are distant from the current position.

Concise model data viewing

LMS Virtual.Lab Motion Rev 7 introduces Motion Mechanism Reports in ASCII format. A complete report, including model data and solver related settings generated in readable text format, makes it very practical to compare different versions of motion models. Engineers save lots of time by utilizing standard text editing tools to detect model definition changes and errors, without clicking through countless software menus. Motion mechanism reports are also very effective in storing model parameters and solver settings for documentation purposes.

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LMS Virtual.Lab Landing Gear reduces errors and saves time in landing gear engineering

In response to the growing demand for dedicated tools for aircraft engineering, LMS Virtual.Lab Motion Rev 7 introduces a dedicated simulation solution for landing gear system development. The new solution allows development teams to build detailed aircraft landing gear models, reliably simulate their real-life performance, quickly assess multiple design alternatives and optimize aircraft designs before prototype building.

LMS Virtual.Lab Landing Gear supports development teams in gaining a detailed insight in the dynamic behavior of the landing gear, and its overall performance in terms of reliability, stability and safety. During landing, take-off and taxiing maneuvers, huge amounts of energy must be absorbed by the landing gear assembly, without generating reaction forces that exceed the dynamic loads envelope.

The Landing Gear solution offers the capability to simulate the kinetic energy that is absorbed by the landing gear typically an oleo-pneumatic design as the aircraft lands and taxis. LMS Virtual.Lab Landing Gear takes the flexibility of components and the operation of control systems into account to accurately calculate loads on components and the complete landing gear under a wide range of operating conditions. For example, landing gear retraction and extension can be simulated to size the actuators and hydraulic valves that drive these maneuvers. Takeoff, landing, taxiing, symmetric and asymmetric braking and other ground maneuvers can all be accurately simulated to validate the correct functioning and the safety limits of new landing gear designs. To investigate aircraft landing event in greater detail, LMS Virtual.Lab Motion Rev 7 supports drop test simulation, which accounts for landing conditions that are specific for aircraft touch down. In simulation, landing gear wheels are spun up-front to be able to realistically simulate the effect of spinning wheels touching the aircraft runway.

LMS Virtual.Lab Landing Gear includes a dedicated user interface which is fully customized to the specific modeling and simulation process for aircraft system integration and landing gear engineering. This allows users to build their design from pre-defined and fully parameterized landing gear templates or to create their own landing gear configuration template. To assure a realistic representation, the models include tires, wheels, brakes, telescopic oleo damper struts and linkages to brace and retract the system. The models incorporate aerodynamic loads and information about retraction, deployment, take-off, landing and ground maneuvers. Based on the model parameters, LMS Virtual.Lab automatically assembles the complete landing gear model, applies the ground load cases, runs the simulation and performs standardized post processing of the results. This integrated process simplifies modeling efforts, removes potential modeling errors and supports the quick assessment of design alternatives.

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LMS Virtual.Lab Durability Rev 7 -Focus on productivity

LMS Virtual.Lab Durability allows users to quickly explore and optimize the structural strength and fatigue life of many different design options on component and system assembly level. LMS Virtual.Lab Durability executes fast and accurate durability predictions. Its dedicated post-processing capabilities provide engineers with immediate feedback and insight regarding all critical durability areas.

LMS Virtual.Lab Durability Rev 7 provides all the automation functionalities to define a complete durability analysis case from scratch. The software can interpret a definition file or interpret an existing job definition file from LMS FALANCS, the predecessor of Virtual.Lab Durability. This allows users to continue using existing processes and to limit the migration effort from the legacy platform to Virtual.Lab. In addition, they will benefit from the powerful Virtual.Lab toolset to define templates and to efficiently automate the preparation of loads and post processing cases. Furthermore, the automation functionality provides extensive flexibility to interact with external optimization tools.

With Rev 7, LMS Virtual.Lab adds the remaining key functions of LMS FALANCS to the new-generation platform. Virtual.Lab Durability enables users to create local data curves for the Dang Van fatigue parameter. The typical Dang Van graph of the shear stress versus the pressure in comparison to the material parameter can be displayed. Furthermore, the safety factor as well as the shear stress and the pressure can be displayed as a function of time. Compared to FALANCS, the creation of the local data curves has become much easier to use, for example through the interactive selection of evaluation points.

For special load schedules, the FALANCS fatigue solver provided the ability to also take into account intermediate residuals. LMS Virtual.Lab can now also start the fatigue solver in this mode. In addition, Rev 7 adds an additional load filter to the unique nodal elimination technique. This new addition further accelerates the already record braking calculation runs, without compromising the reliability of the solver.

The stress gradient method was enhanced to take into account that several materials show different stress gradient effects for large stress events compared to small stress events. Additionally, the stress gradient method can now also be used on shell structures as well as for strain-life based calculations. These enhancements further improve the reliability of durability simulation results.

Rev 7 of Virtual.Lab Durability also aligns the spot weld analysis tool to the same detection algorithm as the connection modeling tool. This delivers an improved transparency while working with different modules of Virtual.Lab. Virtual.Lab also offers more spot weld analysis methods with Rev 7, like the automatic insertion of fine durability spot welds.

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Addressing advanced acoustic challenges with LMS Virtual.Lab Acoustics Rev 7

Accurately predict and solve aero-acoustic noise problems

The new LMS Virtual.Lab Aero-Acoustic solution helps engineers to accurately predict and solve aero-acoustic noise problems, ranging from fan noise in electrical appliances, wind noise in a vehicle to turbulence-based noise in aircraft. Virtual.Lab Aero-Acoustic predicts the noise which is generated due to unsteady phenomena in a flow, which deliver a much more accurate assessment of the acoustic source and resulting sound pressure levels compared to a traditional boundary element analysis. Aero-acoustics simulations start by running a CFD analysis that includes sufficient information to extract time varying pressures on surfaces.

To process the output of the CFD analysis, LMS Virtual.Lab interfaces with most of the leading CFD packages, including CFX, SC TETRA, PowerFLOW, FLUENT. LMS Virtual.Lab Aero-Acoustics converts the time varying pressures into acoustic sources.

Time varying pressures can for instance result from the moving blades of a fan used in a vehicle cooling system or an air-conditioning unit. In this case, an FFT analysis is performed on the CFD data followed by an integration of the blades to obtain the blade forces in different segments. Alternatively, the time varying pressures can result from unsteady pressure fluctuations on surfaces, for example the aerodynamic turbulences acting on a vehicle body. For these phenomena, Virtual.Lab performs an FFT on the CFD data, followed by a data transfer from the CFD mesh to the acoustic mesh.

In both cases, the processing results of the time varying pressures can be used as sources within a classical BEM analysis. This efficient and cost-effective solution results in relatively small acoustic models that are easy to create, handle and check, yet providing accurate solutions to real-life problems.

Performance improvements

Faster simulations result in valuable information earlier in your design process. To achieve this, numerous improvements were implemented to the core acoustic technologies in Revision 7A. These improvements include speed improvements for reading and writing large data files, mapping vast amounts of data between structural and acoustic meshes and an overall process improvement. And as a recent benchmark at a US Automotive OEM has demonstrated, the analysis of large industrial-size models benefits enormously. It delivered such an overall performance boost, the analysis time was brought back from days to hours.

Accelerating transmission loss simulation

Rev 7 of LMS Virtual.Lab Acoustics introduces a new capability to evaluate the transmission loss through shell structures, which indicates the airborne passage of sound or noise through a solid barrier like a vehicle door. The BEM Baffled capability allows calculating the transmission loss without having to explicitly model the so-called diffuse field source room, nor the anechoic receiving room. Users simply create the structural mesh of the panel or shell structure, and subsequently create a BEM mesh and a structural surrogate mesh up to the desired frequency of analysis.

LMS Virtual.Lab applies a Baffle, representing the reflecting, non-transmitting boundary conditions around the plate. This actually simulates the classical transmission loss measurement with a diffuse field on the one side and an anechoic room on the other side of the panel. A straightforward vibro-acoustic analysis then calculates the transmission loss across the panel. The fact that users only have to model the panel obviously represents a considerable productivity increase.

Apply multiple material properties with Multi-domain DBEM

One limitation of the Boundary Element Method (BEM) is that you can only apply a single acoustic material property. With the Indirect BEM (IBEM) method, a single material property is applied to the entire model, both on the inside and the outside. The Direct BEM (DBEM) method allows the application of a material property on either the interior or exterior of the model. This means that Direct BEM applications are typically limited to a single domain, meaning that they can either treat the outside or the inside of a closed volume like a vehicle or an aircraft. But the analysis of specific phenomena like aero-acoustics requires the capability to handle multiple domains (interior and exterior) in a single run. The Multi-domain DBEM capability deployed in LMS Virtual.Lab Acoustics Rev 7 addresses this requirement. Users can create a separate DBEM model of the 2 domains, and then define the relation between the 2 regions (e.g. an open hole or a perforated plate). Virtual.lab Acoustics solves the BEM analysis for the 2 domains in a single run. This gives the user the possibility to apply multiple material properties like temperate or pressure differences in a boundary element model.

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LMS Virtual.Lab Noise and Vibration Rev 7 - Efficiently analyze, refine and optimize noise and vibration performance

LMS Virtual.Lab Noise and Vibration is specifically developed to efficiently analyze, refine and optimize the vibro-acoustic behavior of a design. It offers all the required tools to create system-level models, build realistic load cases and simulate noise and vibration responses.

It includes a wide range of visualization and analysis capabilities dedicated to noise and vibration engineering. Convenient tools enable engineers to quickly perform design modifications and to assess the noise and vibration performance of a design variant in a couple of minutes.

Rev 7 of LMS Virtual.Lab Noise and Vibration features an extensive set of new and improved post-processing tools to increase overall productivity. When engineers perform a noise and vibration analysis for different load conditions and response points, this typically results in a large number of curves. In order to easily analyze the overall performances, the new Performance Table feature creates a table showing a multitude of sensors (RMS, RSS, Min, Max,÷ ) for multiple load conditions and hard points. This facilitates the easy handling of a large number of data to quickly retrieve the right conclusions.

With Rev 7A, users can easily create user-defined displays, for example to compare different curves from different analyses. The Layout Editor allows the creation of specific displays, which can be filled with Virtual.Lab data in a customized way. The user defines the functions he wants to see and interactively adds them to the display. The associativity is kept during this operation, making it possible to apply specific filters to the data sets and adding the requested function data to a display.

LMS Virtual.Lab Noise and Vibration gains more reporting efficiency with Rev 7, by fully automating copy and paste operations. For example, users can automatically create displays of the critical locations and paste these into a report. Virtual.Lab images can also be directly pasted to the windows clipboard for further use in MS Word or PowerPoint.

In the early concept stage of a vehicle, the exact forces that will go into the body are not yet known as the vehicleÌs structure is still under development. Often engineers only have access to road displacement excitation data, which are vehicle independent. This road excitation is random and therefore expressed in terms of auto spectral densities. The new Random Forced Response tool in Virtual.Lab starts from such random inputs and directly performs a random forced response to obtain the cross spectral densities responses. This can be processed to obtain referenced frequency spectra, to be used later on to perform a regular Forced Response and Contribution Analysis.

SPoints allows the study of participation of component modes to a response of the full assembly. A supplier, for example, that has to build an extra piece on top of an already existing structure which he cannot change, can focus on improving his own components to obtain a better response of the full assembly. Also, whenever structural modes are used for acoustic analysis, changing your structure (by using modification prediction or coupling it with another component) normally means that all the analysis steps using the structural modes have to be recomputed. The use of SPoints allows users to keep using the dynamics of the old unmodified structurewhich accelerates the analysis of structural changes.

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LMS Virtual.Lab Structures Rev 7 – Supporting a broader application scope

LMS Virtual.Lab Structures provides a scalable solution for structural modeling and analysis, integrating advanced model creation and manipulation tools to efficiently generate component, subsystem and full-system models. With integral full meshing capabilities, LMS Virtual.Lab captures the complete modeling and analysis process, from CAD drawing to multi-attribute simulation results. After the integration of these meshing capabilities in the previous release, over 400 functions were streamlined and reorganized in Virtual.Lab Structures Rev 7 for optimal ease of use and productivity.

The structural analysis software continues to expand its pre and post-processing capabilities and covers and increasing number of user scenarios. New capabilities include mass and inertia sensors, beam and bar extensions, model checking extensions, composite failure index post-processing, superelement postprocessing, trimming detection, etc.

LMS Virtual.Lab Structures Rev 7 also expands its Nastran pre/post capabilities for acoustic and vibro-acoustic analysis, taking advantage of the recent solver enhancements in Nastran 2004 and 2005 and an improved cavity mesher algorithm. A comprehensive set of post-processing functions is available including panel and modal contribution analysis. Manuel Etchessahar from the Vehicle Engineering CAE group at PSA PEUGEOT-CITROËN stated “The new developments enable us to use LMS Virtual.Lab as pre/post processor for Nastran based acoustic and vibro-acoustic analysis and to quickly set-up, run and fully post-process our typical vehicle models”.

Also, users can now directly and easily set-up Nastran DMIG reduction jobs and use DMIG super element representations in assemblies, next to the already available modal superelement representations. These can for example include components that are described by mass and stiffness matrix in an assembly (e.g. a tire in a car assembly). This capability results in faster run times and facilitates the exchange of model information.

LMS Virtual.Lab Structures gains another important productivity feature with the capability for scripting of Nastran static case and nodes/elements renumbering. Users can script the complete setup of the Nastran static case with all parameters. This scripting function allows users to customize processes or automate the setup of specific processes. The renumbering scripting allows the users to apply a predefined numbering on a model, saving a lot of manual manipulation.