5
MSC Software: Debunking 5 Myths of MBD Whitepaper WHITEPAPER Debunking the Five Myths of Multibody Dynamics Simulation Hemanth Kolera-Gokula, Product Marketing Manager, Adams

Debunking the Five Myths of Multibody Dynamics …...2019/11/18  · MSC Software: Debunking 5 Myths of MBD Whitepaper WHITEPAPER Debunking the Five Myths of Multibody Dynamics Simulation

  • Upload
    others

  • View
    17

  • Download
    0

Embed Size (px)

Citation preview

Page 1: Debunking the Five Myths of Multibody Dynamics …...2019/11/18  · MSC Software: Debunking 5 Myths of MBD Whitepaper WHITEPAPER Debunking the Five Myths of Multibody Dynamics Simulation

MSC Software: Debunking 5 Myths of MBD Whitepaper WHITEPAPER

Debunking the Five Myths of Multibody Dynamics Simulation

Hemanth Kolera-Gokula, Product Marketing Manager, Adams

Page 2: Debunking the Five Myths of Multibody Dynamics …...2019/11/18  · MSC Software: Debunking 5 Myths of MBD Whitepaper WHITEPAPER Debunking the Five Myths of Multibody Dynamics Simulation

2

WHITEPAPER MSC Software: Debunking 5 Myths of MBD Whitepaper

Introduction

Physics-based simulation has become an integral part of engineering product development

processes, across physics types and industries. Engineers in the automotive, aerospace, heavy

machinery and energy industries commonly utilize Multibody Dynamics (MBD) simulations to model

complex assemblies with parts in motion, and its applications are increasing as organizations face

complex new engineering challenges.

The ability to simulate mechanisms allows engineers to explore interactions between components

and geometric configurations to design control strategies and optimize systems dynamics. All this

can be achieved early in the design process, and without the overhead of constant and expensive

prototyping.

Today, the possibilities of MBD have broadened beyond recognition. The convergence of more

affordable high-performance computing, interoperability standards and advances in solver

technology and simulation methods is helping to bring new insights to mechanism design. While

some organizations are forging ahead, historic constraints and perceptions prevent the use of MBD

simulations where they present significant value to modern engineering development processes.

This white paper focusses on five common myths associated with MBD simulation, and challenges

each with evidence of under-exploited capabilities and the benefits that may be overlooked.

Page 3: Debunking the Five Myths of Multibody Dynamics …...2019/11/18  · MSC Software: Debunking 5 Myths of MBD Whitepaper WHITEPAPER Debunking the Five Myths of Multibody Dynamics Simulation

3

WHITEPAPER

Myth 2: MBD simulations are only used for conceptual design studies early on in the design cycle Though MBD simulations are used heavily during the conceptual design of dynamic systems, their benefits extend through all phases of the design cycle.

MSC Software: Debunking 5 Myths of MBD Whitepaper

Myth 1: MBD Simulation = Motion Analysis MBD simulation solves a rich set of inter-connected systems that stretches far beyond merely simulating the motion of constrained mechanisms. Leading organizations don’t optimize in silos but collaborate across disciplines to trade off parameters and achieve the desired system-level optimizations. For example, automotive manufacturers have cross-functional teams focused on mechanism durability, safety and noise and vibration. MBD simulations enable this collaborative development and serve as a common foundation across these groups to enable system-level design.

The breadth and the depth of MBD simulation applications can be visualized concisely by considering the response frequencies and amplitudes that are of interest. Consider the engineering of a vehicle, for example. Simulations of vehicle handling are primarily focused on low-frequency responses associated with vehicle events, such as a vehicle cornering. At the other end of the spectrum, applications simulating vehicle ride and NVH (Noise, Vibration & Harshness) characteristics capture phenomena related to higher frequencies and lower amplitudes, such as the vehicle response to bumps on the road or the impact of drivetrain vibrations on the occupant. Durability engineers work across the frequency spectrum to study the effect of various ride, handling and NVH design attributes on vehicle loads.

The frequency characteristics in an MBD simulation dictate the level of detail and fidelity required in the model. In general, the higher the frequency response, the higher the model fidelity required. Users create model variants tailored to capture the system response of interest. To manage these differing use cases centrally, the more advanced MBD simulation solutions now incorporate multiple vehicle configurations in a single model assembly, and multiple configurations within a single sub-system. In this way, a single model database can be created that represents vehicle configurations to various levels of fidelity (flexible, beam, rigid) and tailored to specific frequency responses (handling, ride, durability). This approach makes it possible to efficiently maintain those configurations as the model is enriched and refined with new data and refinements from all parties.

Page 4: Debunking the Five Myths of Multibody Dynamics …...2019/11/18  · MSC Software: Debunking 5 Myths of MBD Whitepaper WHITEPAPER Debunking the Five Myths of Multibody Dynamics Simulation

4

WHITEPAPER

is not limited to studying broad system-level effects. Today, MBD is being applied to model highly complex physics at a component level. Furthermore, a high level of physical accuracy can be achieved when the right inputs (e.g. part compliance, spring or bushing properties) can be provided to the model.

There are opportunities to progressively increase the fidelity of the MBD model as progress is made in the product development process. The topology for a mechanism is identified using initial MBD analysis, following which analysts can incorporate CAD to detail individual parts. FEA based on the CAD data then provides detailed part compliance, enabling the creation of flexible bodies that can be used to further enhance the fidelity of the MBD model. At every stage, the MBD systems model can be aligned with the level of engineering information available to ensure the best possible fidelity.

Of course, bigger is not always better. As with any simulation technique, MBD models must be tailored to the level of physical fidelity required for the intended simulation. For example, the fidelity of the model used for vehicle handling analysis can be further refined to capture responses in the ride frequency regime. These extensions are made through higher fidelity representations of components such as dampers, bushings, hydro mounts and tires.

Co-simulation is another avenue for improving model fidelity. It is increasingly common to couple MBD models with FEA tools to simulate complex component-level behavior such as large deformations or non-linear materials. High frequency acoustic simulations are coupled with MBD models to enable product designers to study the sources of noise and to assess how structural design changes can help them decrease the noise transmitted to the environment.

Myth 4: Using MBD simulations requires specialist knowledge Exploring the behavior of systems using simulation has traditionally been the domain of simulation engineers or analysts. Complexity in simulation interfaces, or in simulation techniques and procedures, created the need for highly specialized users. A lack of standards for model exchange and interoperability compounded these issues.

In the field of systems dynamics simulation, MBD analysts have been the gatekeepers of simulation models. However, as engineering simulation takes a central role in design and development, there is

During engineering development, system-level targets are identified and cascaded down to the sub-system and component-level. Component, sub-system, and full system prototypes are then developed and validated for performance using a variety of simulation solutions based on the physics and application.

In the automotive industry, higher-level targets for ride and handling characteristics are influenced by the road loads and the configuration of the suspension and chassis. MBD simulations serve as an ideal tool for conceptual investigations of mechanical systems and sub-systems to tune characteristic properties like mass and stiffness in critical locations. These conceptual models can be quickly designed and explored before any detailed design information is available.

Opportunities to leverage MBD simulation also exist during the validation phases of the development cycle. For example, aircraft manufacturer Airbus previously validated various regulatory requirements by building test rigs that deflect structural assemblies to simulate high lift configurations and ensure full operation of control surfaces. The approach had multiple disadvantages: the need to have already manufactured the wing system, the time and cost of testing, and the cost associated with fixing problems uncovered by testing. Airbus has now combined Finite Element Analysis (FEA) and MBD simulation through the design process to offset the level of physical testing required to demonstrate regulatory compliance.

In recent years, affordable high-performance computing and faster solvers has enabled MBD models to be used in road vehicle testbeds as part of Hardware in the Loop (HiL) and Driver in the Loop (DiL) test systems for system test, validation, and calibration. The ability to use real and virtual sub-system definitions on a testbed makes vehicle testing cheaper and more efficient by reducing the need for physical test prototypes.

The use of MBD simulations is no longer limited to a single phase of the product development process. From conceptual system design to physical testing, MBD simulations have a pervasive impact on the design and development of dynamic systems in leading engineering organizations.

Myth 3: MBD models have limited physical fidelityIn MBD simulations, the most complex part within a mechanism may be represented as a simple link so that its dynamics can be explored at the system level. However, the utility of MBD simulations

44

MSC Software: Debunking 5 Myths of MBD Whitepaper

Page 5: Debunking the Five Myths of Multibody Dynamics …...2019/11/18  · MSC Software: Debunking 5 Myths of MBD Whitepaper WHITEPAPER Debunking the Five Myths of Multibody Dynamics Simulation

WHITEPAPER

For this reason, real-time compliant vehicle dynamics models for HiL and DiL integration have traditionally involved a low number of Degrees of Freedom (DOF), typically around 20. Such models are typically used to characterize the behavior of the body via lookup tables. While these Reduced Order Models (ROMs) are a valid approach for some applications, compromising on the number of DOF’s is no longer a requirement for real-time computation.

Readily available high-performance computing and advances in engineering simulation techniques have now made higher fidelity real-time simulations possible, providing more valuable insights. Real-time simulations now provide an opportunity to connect physical components and virtual models in Hardware in the Loop (HiL) and Driver in the Loop (DiL) automotive test environments.

For example, MSC Software has designed Adams Real-Time, to preserve the topology and parametrics of the MBD-modelled system in real-time applications. This makes it possible to maintain elements such as hardpoints, joints, springs, dampers, and bushings and make modifications without the need to calibrate a new ROM for every change. As such, the model can capture higher frequency characteristics in the system responses, and different configurations can be introduced and explored with a shorter turnaround time. Adopting a one tool, one model approach for both real time and non-real time applications eliminates error-prone model translations between different tools. This approach also makes it possible to tune and optimize systems very efficiently and has the potential to remove weeks from a typical vehicle development program.

Conclusion In recent years, MBD simulation has evolved beyond the myths that persist in all industries today. Leading engineering organizations are taking advantage of technology advances, using multi body dynamics to manage complexity and fuel collaboration to get designs right the first time. Today MBD models can contain highly accurate representations and they can be leveraged by more engineers, across diverse disciplines, without the need to be simulation specialist.

MBD simulation can provide valuable insight and understanding of any system, throughout the product development cycle, and it can be leveraged with hardware to validate sub-systems to a high degree of confidence before a physical prototype of the system is built. If you thought any of these myths were true, then it could be time to re-evaluate how you can more effectively leverage MBD in your design process.

a growing need to democratize access to simulation models and modeled information. To this end, the simulation software providers have endeavored to capture the knowledge and skill of the analyst within their models. This encapsulation makes it easier for other engineers to leverage valuable work to explore how the modelled system integrates with other systems, and to investigate the design trade-offs and optimizations that matter to them.

There are several ways to improve access to MBD models. One approach is to institute tool-independent standards that enable a “plug and play” approach to utilize highly advanced models via more streamlined interfaces. The Functional Mockup Interface (FMI) is a tool-independent standard for CAE model exchange and co-simulation. FMI makes it possible to import models into other tools that conform to the standard by representing MBD models as a Functional Mockup Unit (FMU). This approach allows simulation engineers that are not MBD specialists to use an MBD model, but without the need to understand the inner complexity of the model or how to interface with the simulation software that created it.

Simplifying the user experience is another approach to help organizations improve access and derive value from MBD models. For example, MSC Software created Adams Explore in an effort to make high-end simulation models available to engineers that are not simulation specialists. The MBD simulation engineer can export an Excel spreadsheet that represents the MBD model using the Explore plug-in. This simple Excel spreadsheet is then be used by the Design engineer to change their parameters of interest, run the MBD model, and review the results to study the effect of their design changes on the system.

Myth 5: Real-Time MBD simulations = Reduced Order Models (ROMs) A real -time simulation mandates that the virtual model delivers a response/solution output at specific time increments in the same or less time than the physical system. This way, the state of the virtual system is always synchronized with the physical components to provide an accurate testing environment.

MSC Software: Debunking 5 Myths of MBD Whitepaper

For more information on MSC Software MBD Solutions visit: www.mscsoftware.com/application/multibody-dynamics

MBD*2019SEP*WP

©2019 MSC Software is part of Hexagon (Nasdaq Stockholm: HEXA B), a global leader in sensor, software and autonomous solutions. Learn more at hexagon.com and follow us @HexagonAB. The MSC Software corporate logo, MSC, and the names of the MSC Software products and services referenced herein are trademarks or registered trademarks of the MSC Software Corporation and/or its subsidiaries and affiliates in the United States and/or other countries. All other trademarks belong to their respective owners. All rights reserved.