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Turning NVH Engineering into a Competitive Advantage
Download the free of charge NVH engineering white paper for automotive suppliers
 OEMs are increasingly involving suppliers in their engineering process. But how can suppliers deliver components and subsystems with the right NVH performance ‘by design’, and yet control costs and risks? How can they systematically achieve highly competitive levels of NVH performance? In this white paper, you will learn how: - Prototype costs can be reduced by validating NVH characteristics from simulation models;
- Development time can be shortened by front-loading the development process with design rules derived from previous projects and benchmarking of competitive products;
- A close cooperation between carmakers and suppliers in all phases of the development process can create a win/win situation for both.
1. Challenges of the Automotive Industry  The automotive industry certainly is one of the most competitive in the world. Manufacturers are under intense pressure to develop and deliver innovative vehicles in less time, all while keeping costs in line and maintaining high standards for safety, quality, and durability. There is an increasing range of customers to satisfy in global markets, and the number of models to meet this expanding demand is expected to more than double over the next five years.
"Time-to-market" is particularly critical with automotive manufacturers in a race to the showroom floor with new models. Companies first to market typically capture greater portions of overall sales, and even a few weeks of delay can result in millions of dollars in lost revenue. Industry statistics indicate that vehicle development time was in the range of 48 to 60 months in the early 1990s and is currently averaging 24 to 36 months. Some automotive manufacturers have compressed the process to develop a new variant on an existing platform to 18 months. On the horizon is the 12- month car, described as "the gleam in the eye of the automotive industry" by Dr. David Cole, President of the Center for Automotive Research at the Altarum Institute.
Compounding the challenges in satisfying these demands, car companies must meet stricter environmental regulations for exterior noise and increased customer expectations for noise, vibration, ride, handling, and the overall feel, comfort and sound of the vehicle. These attributes constitute the strategically important brand value of the vehicle that differentiates a manufacturer’s vehicles from its competitors. A Jaguar has a certain ride, for example, a BMW has a unique feel in the way it handles, and a Harley has a distinctive sound riders want to hear from classic heavyweight motorcycles.
Since noise and vibration represent such a significant contribution to the brand image of a vehicle, OEMs are vitally concerned with getting these attributes right. Developing components, subsystems and the complete vehicle to the required levels of noise and vibration characteristics by using computer-based simulation, testing and analysis tools, is referred to as NVH (Noise, Vibration, Harshness) engineering, representing one of the most complex and strategically important aspects of automotive development.
2. Suppliers Transition from Parts Makers to Development Partners
One response for automakers in meeting the challenges of shortening development time and reducing costs is to ask suppliers to take on growing levels of engineering responsibility. Suppliers seeking to differentiate themselves within their market have eagerly embraced this opportunity, investing heavily in noise and vibration tools, technology and expertise. However, it is an opportunity that also imposes demanding new challenges.
"Subcontractors that formerly built made-to-order parts and assemblies for automakers based precisely on designs handed to them by the OEM, now must be concerned with developing their own designs according to functional performance characteristics required by the OEM," explains Ed Miller, president of consulting and research from CIMdata Inc.
Thus, the role of many companies in the supply chain, most especially in the automotive industry, is shifting from parts fabricator to solution provider. To meet the new requirements, partnering and collaboration between the automakers and their suppliers has become standard practice as they work to implement design, simulation, analysis and testing capabilities that previously were the exclusive domain of the OEMs.
Competitive pressure, environmental legislation and the quest for customer satisfaction force OEMs to set stringent NVH targets. OEMs now tend to outsource full design and performance responsibility for complete subsystems such as corner modules, complete axles, front-end modules, trimmed doors and cockpit modules.
Tier 1 suppliers will typically take complete responsibility for their module including the roll-down of module
requirements to requirements for individual components, the selection and coordination of tier 2 suppliers, controlling the development and production costs and finally organizing fabrication and delivery.
Suppliers of components where NVH is not a primary product attribute might suddenly be confronted with an unfamiliar NVH requirement because of their increased responsibility for all aspects of their component or subsystem. Although a rubber hose does not make noise on its own, it can radiate considerable noise when connected to an air-conditioning compressor.
Either way, suppliers are undergoing considerable process change in using increased levels of NVH technology in the development of a wide range of automotive components including exhaust systems, engine parts, tires, shock absorbers, bushings, seals, and powertrains. Succesful suppliers leveraged their expertise and NVH technology to transform themselves from automotive parts suppliers into total solution providers. All these companies have some type of strategy to:
3. Putting an Optimized Process and the Appropriate Tools in Place
3.1 From "Test-Analyze-Fix" to "Design-Right-First-Time"
Traditionally, NVH issues have generally been treated by a "Test-Analyze-Fix" troubleshooting approach where hardware prototypes are physically tested at the final stages of development when design changes are the most time-consuming and expensive to make. When errors aren’t caught until later in the cycle during prototype testing, considerably more time must be spent updating design files, approving engineering changes, and re-testing hand-built car mock-ups that may take months to construct and cost $300,000 to $500,000 each.
Vehicle designs also may be far less than optimal in this type of build-and-test approach. Quick-fix changes to meet scheduling demands solve a problem in one area, but often cause an unintended vibration or resonance to occur in other parts of the vehicle. Moreover, spot-fixing such isolated problems often detracts from the overall design, when grossly overdesigned components add needless weight and bulk to damp out noise.
This process seems at odds with the requirements for efficient product engineering. However, it follows almost naturally out of the cross-attribute nature of NVH, as a phenomenon that only manifests itself on the vehicle level, as well as from the "bottom-up" approach of designing components and assembling them into subsystems that comprise the total vehicle.
In moving from this "Test-Analyze-Fix" approach to "Design-Right-First-Time," it is important to set targets for individual components , take these targets into account from the start of the design process and then validate these targets early in the development process using virtual prototyping technology before building the physical prototypes. Such an approach shifts the balance of engineering activity from troubleshooting during prototype testing to analysis early in the conceptual stages.
3.2 Setting Targets in the Concept Phase
The NVH engineering process in place at carmakers (illustrated below and often referred to as "Engineering in V") makes such a structured approach possible. This process has three major phases. In the concept phase, the engineering process progresses basically top-down from full vehicle targets to subsystem and component requirements. In the design and development phase, the basic movement is bottom-up: driven from the design activity on component and subsystem level. In parallel with this digital design and development phase, there is (after a certain delay) the verification phase where physical prototypes are built for validation.
 In the concept and planning phase, NVH is dealt with in terms of setting targets for overall vehicle performance characteristics. Vehicle targets are typically based on "the voice of the customer" captured through customer satisfaction studies and their correlation with objective engineering metrics such as interior noise levels, together with the corporate positioning of the new vehicle, and environmental legislation. In the concept stage automakers evaluate concepts for subsystems such as engine mounts or a suspension and evaluate the trade-off between various attributes for each of these concepts. Different layouts for the position of the engine mounts, for example, will have their own unique NVH characteristics and consequences for packaging and price. The basic choices made in this concept phase will highly influence the quality of the final product.
Once vehicle concepts and layout are fixed, global full-vehicle targets can be cascaded down to subsystems and components. This can be done by applying a "system approach" to NVH (see related side story on page 9) where every output (steering wheel vibration or exterior noise, for example) can be described by certain inputs and the system characteristics between inputs and outputs. This approach can be applied to the full vehicle but also to smaller subsystems and components, where the output from one subsystem can be the input for another subsystem.
Typical target functions on a module or component level include dynamic stiffness, the point mobility of specific connections, resonant frequency, mode shape, maximum displacement of a point under specific loads, radiated sound power, etc. These requirements describe the functional space, the context in which the designer can work.
Apart from the characteristics of the component itself, boundary conditions must also be defined for other
components or subsystems. A part designed to be attached to a perfectly rigid body might perform quite differently when installed in a flexible connection point. Important boundary conditions include: flexibility of the connection point of a component to the rest of the structure (expressed as point mobility or structural impedance), and typical/ maximum loads (imposed displacement, induced forces, induced pressures, etc.) Simulation and testing of components have to be done taking these boundary conditions into account.
3.3 Integrating NVH into Digital Development  All major automakers, as well as companies in a wide range of other manufacturing industries, are using virtual prototyping as a way of integrating NVH into the product development process and avoiding excessive physical testing.
Starting from the CAD model geometry, dynamic characteristics of components like resonance frequencies and point mobilities can be calculated using Finite Element Analysis (FEA) while acoustic radiation software helps to pinpoint acoustic hotspots or determine acoustic modes. This enables companies to evaluate the structural and acoustic characteristics of their components from CAD data without building a hardware prototype. As soon as physical prototypes become available, comparing simulation results with those measured on the actual parts and updating the predictive models to bring the predicted results in line with the observed ones, can further refine these models.
 The real-life performance of components can be evaluated by loading them with the forces or imposed vibrations that they will experience in operation. Simulation packages can calucate loads such as exhaust system pressure fluctuations, from an engine combustion simulation code. Or it can be measured on a test bed or mule vehicle or taken over from a previous generation vehicle.
Models of individual components can be assembled to build models for subassemblies, complete modules and finally the full vehicle. These component models can be a mixture of simulation and experimental models. This "hybrid simulation" approach makes it possible to use the best dynamic model available at any moment in time. This allows to use experimental models for those components that are carried over from previous-generation models, components that are hard to model or where a supplier has no access to. As prototypes become available, simulation models can be "calibrated" to improve the accuracy and reliability of NVH simulation
predictions.  Working with CAD, CAE, and Test applications traditionally means reworking models, duplicating mesh representations, and copying information from one system to another because of differences in data formats, incompatibilities between systems, and lack of standardization. Moreover, companies typically run into considerable difficulty trying to optimize product performance for multiple variables, with designers typically dealing with each variable separately and hoping conflicts will be minimal.
An integrated software environment overcomes these challenges by providing a unified, graphical engineering desktop and automated features for conveniently combining and synthesizing system models and loads from design, test and simulation. Such a platform offers full associativity across multiple applications and disciplines, with links to leading CAD systems, Finite Element codes, test data sources, multibody dynamics, acoustic radiation prediction, fatigue-life prediction, and many other CAE systems that otherwise would run separately and produce isolated results. This means, for instance, that once virtual loads are applied to calculate the vibration response of the assembly, the structural responses can be used immediately to predict fatigue life, vibration, noise, and other functional behavior.
This streamlines the process of building models, assigning loads, running the specific applications, and visualizing the results in application-specific formats. This way NVH simulation tools help to capture and leverage a company’s knowledge of its products and the processes it uses in developing them.
3.4 More Than Just Meeting NVH Targets
Multidisciplinary optimization tools are extremely valuable in this process of integrating NVH into the total design process of components, assemblies, subsystems, and the full vehicle. Optimization software is used extensively to balance NVH attributes with other often conflicting constraints such as cost, size, weight, strength, durability, etc. The optimization software coordinates numbers of runs of multiple-application packages and compares results to arrive at a design which optimizes certain design objectives while satisfying the imposed constraints: the thickness of a component can be reduced to lower weight and cost, while making sure that the resonant frequencies lay outside the operating range of the vehicle and the maximum stress is below a certain threshold.
However, suppliers often do more than just making sure that a component complies with certain targets. Beyond that, the influence of manufacturing variations on component characteristics early in design can be shown, for example. Based on a set of parameters describing all possible production variations, DOE (Design Of Experiment) tools help assess a minimum set of design variations to be simulated to determine the variability of the product characteristics.
3.5 Front-Loading the Development
 Process with NVH Testing Moving away from test-based troubleshooting and putting an increased emphasis on NVH issues in product development is radically changing the role of testing in the NVH-engineering process. Of course testing is still needed to validate full vehicle NVH characteristics. But the primary goal of testing is now shifting to front-loading the development process. This can be done by benchmarking NVH characteristics of alternative layouts, by collecting operational loads to be used later to load simulation models, by experimentally modeling components, or by providing valuable insight into the contribution of specific components to full vehicle NVH characteristics.
Instead of doing ad-hoc troubleshooting activities in the later stages of particular programs, testing is becoming standardized at a growing number of companies, with the aim to systematically collect and identify dynamic data and models.
This approach also puts specific requirements on the measurement systems, used both in the vehicle and in
the laboratory, by acquiring data from a wide range of transducers including digital heads and rpm signals from relevant rotating and moving parts. Some of the best tests generally are performed in a consistent manner by capturing the company’s corporate procedures in templates, providing standardization in the methods of gathering data. Automated capabilities in these test systems save time by helping users set up measurements on multiple channels, by organizing the data into the proper categories and formats, and by creating necessary reports.
A typical test lab can easily generate huge volumes of information, so a data management system often is used for organizing and providing ready access to plots, models, graphs, statistics, images, databases, and other media. This allows engineers to retrieve information without having to know precisely where it resides. A web-based solution also enables access to data to those outside the test department, including groups such as simulation and design as well as individuals in external organizations such as the OEM and partner companies. It enables the component supplier as well as project engineers and managers to make well-informed decisions taking into account all applicable information and to communicate this knowledge to others.
4. Building Competence in NVH
 Contending with NVH represents one of the most demanding and nerve-wracking phases of automotive design, especially knowing which materials and parts to use, how to size components, and where to place them. Isolating sources of sound and vibration among the thousands of intricately interconnected parts is extremely difficult. Because of the mechanical complexity of a vehicle, correcting a problem in one part of the car often triggers others in different areas.
Some of the most successful suppliers have learned through experience in the automotive industry what the overall NVH objectives are for their OEMs and how the individual parts they provide fit into this big picture. They recognize the complexity of overall vehicle NVH, know the design goals of the automaker, speak the same language as the OEM, and understand how individual components contribute to the overall vehicle NVH.
 Test-based NVH analysis tools can help to create these insights. Modal analysis, for example, provides an understanding of basic structural properties of the supplier’s product. TPA (Transfer Path Analysis) can be used to investigate the influence of various structure-borne transfer paths from sources such as the engine or road, for example, at specific frequency or rpm ranges. ASQ (Airborne Source Quantification) and acoustic holography pinpoint acoustic sources. Sound quality analysis tools determine which signal characteristics contribute to sounds, either ones that are desired or those that are unwanted. Building up a knowledge base of component and vehicle characteristics by systematically benchmarking own and competitive products, can be extremely helpful in selecting and specifying parts for a comparable new vehicle. Often, design teams find that investigating how certain parts performed on former vehicle models  can save considerable time in developing parts for a new vehicle and understanding the influence of different materials and design alternatives. NVH simulation tools make it possible to quickly evaluate the influence of different design parameters on NVH characteristics and derive from these the design rules that enable product development engineers to make the most appropriate design decisions with a minimum of overhead.
An optimized process and state-of-the-art NVH tools, both for test and simulation, are needed to increase the efficiency of engineering, but at the end people still make the difference. Tools can validate current designs and in the best can give direction on how to improve, but it is still up to the development engineer to make decisions regarding material selection, layout and all the small details that make the difference between a good design and an excellent one. It is the insight, competence and experience of the individual that drives progress.
Tackling Tough Automotive NVH Challenges at BorgWarner
 As an automotive supplier, BorgWarner faces tough challenges in a competitive market where development time and product costs must be continually reduced, often through the use of lighter materials, such as magnesium. This clearly represents unique challenges for noise and vibration. According to Sue Stroope, Supervisor of NVH Engineering at BorgWarner, these demands are always raising the bar for NVH as a key consideration in development of the BorgWarner transfer cases: the box bolted to the rear of the transmission and filled with planetary gearsets and chain drives for distributing torque to both axles in four-wheel-drive vehicles.
Stroope explains that the OEMs set targets for overall vehicle performance characteristics, which the automaker then cascades down to important parameters needed in the design of the transfer case. "The OEM gives us vehicle mounting locations, driveshaft position, and performance features they want in terms of speed and torque ranges," Stroope says. "They also specify packaging requirements to avoid interference with adjacent components under the vehicle such as the catalytic converter, transmission, heat shields, driveshafts and fuel lines."
"We rely on up-front simulation more heavily to catch and fix any NVH problems early in development," says
Stroope, who notes that designs are more easily optimized and refined in the initial stages of development,  compared to troubleshooting problems in prototype testing and then changing the design. The aim is to reduce reliance on prototype tests because of the time and expense of changing transfer case castings and reworking dies, which can take months to complete and cost thousands of dollars.
When parts become available, Stroope says physical testing and analysis to accurately measure NVH characteristics in the test lab, especially on the component level, are important tools in helping verify the design and avoiding unexpected trouble on full-vehicle prototypes right before a product launch. "We often vary the type of parts in existing transfer cases to see if a modified gear, fewer pinions, or a lowweight sprocket, for example, improves or degrades the noise level," she notes. "Occasionally we find that parts may be unnecessarily over-designed. Conversely, ideas that may look good to save material end up producing too much vibration." "NVH is a critical factor throughout product development, from concept all the way to final product roll-out," explains Stroope. "In this entire process, LMS technology is an indispensable tool in helping us leverage our expertise to meet our targets."
5. Strategic Transformation of the OEM-Supplier Relationship
Where suppliers previously received component drawings from the OEM and their interaction was mainly limited to discussions on pricing and JIT deliveries, the new approach where suppliers share engineering responsibility with the OEM requires a totally different relationship.
This relationship starts in the concept and planning phase, where basic choices are made that determine to a large extent overall vehicle characteristics in many areas such as ride, handling, and durability as well as NVH. In this phase, the supplier can propose alternative design layouts and indicate the impact of each on other components. Choosing a better window seal, for instance, allows the window supplier to use thinner glass, resulting in weight savings for the OEM. Because of the critical nature of such decisions in vehicle cost and performance, a company’s engineering competence in NVH is often a significant factor in their selection by the OEM.
In each stage, the supplier must provide the carmaker with the necessary information. In the concept phase,
carmakers can incorporate the supplier’s simplified models of possible alternatives in their full vehicle concept models. In the design phase, the supplier provides the OEM not only with digital CAD data and simulation results but also with the appropriate models that the OEM can include in their full vehicle models for NVH. In the validation phase, the supplier builds physical prototypes and tests them.
The OEM’s first prototype of the new vehicle will then only be used to confirm all the validations done before rather than to test individual components. NVH is an important issue throughout this process, so suppliers must work closely with the OEM to get the necessary product characteristics and corresponding boundary conditions.
Some OEMs will provide such NVH characteristics and boundary conditions while others that are not so far along may have to be asked for such information, demonstrating commitment of the supplier to quality products for the OEM. In either case, successful suppliers find it extremely beneficial to exchange as much NVH information as possible with the OEM and openly communicate a desire to provide components that will help the automaker meet its full-vehicle design goals.
In any case, an open communication with the OEM is important to make the cooperation work. This is certainly the case when full vehicle targets are not met. Open discussions on the source of problems regarding target cascading, boundary conditions, or failure of other companies to make their targets can result in a win/win situation.
6. Moving Forward to Strengthen Market Position
Suppliers of a wide range of components, assemblies, and subsystems are currently using various levels of NVH technology to reinforce their position with automotive OEMs. Companies throughout the supply chain are establishing close relationships with customers based on the ability to develop products that will meet the stringent market demands, safety standards, and regulatory requirements.
Such a strategy requires suppliers to:
- Acquire the necessary NVH engineering competence to develop component and subsystem in a global vehicle context;
Deploy the tools for structural and acoustic simulation of components and subsystems, integrated with CAD, other simulation tools and with the test environment; Set up processes to collect experimental data in a systematic way to front-load the development process; Work on the relationship with the carmakers to become real codevelopers from within the concept phase of a new model.
Case study: A System Approach to NVH
The conceptual model of a simple source-transmission-receiver chain is at the core of NVH methodology. Vehicle comfort is translated into terms of noise and vibration, which are regarded as outputs of the vehicle system in response to a multitude of inputs and excitations. The vehicle system acts as a transmitter which may amplify or filter the inputs depending on its dynamical characteristics. This behavior of the vehicle in transferring these inputs depends on the interaction of many different components and subsystems. With this sort of conceptual model in mind, NVH engineering aims to control the source inputs (if possible) and "tune" the transmission of sound and vibration by tweaking the design of individual parts and assemblies. The foundation for this process is understanding how characteristics of the source as well as components and subassemblies all contribute to vehicle NVH behavior. To clarify this conceptual input-transfer-output approach, the case of powertrain-induced interior noise is illustrated in the figure below. Systematically applying this input/output chaining provides a tree-like "cascade" that links NVH quantities at the vehicle level to system, subsystem and component characteristics in a logical and coherent way. Such a system approach enables both the decomposition as well as the synthesis of vehicle NVH-response as a function of the dynamical characteristics of its substructures and components:
Key to the input-transfer-output model is its unifying character, not only between the different modeling technologies in representing the system but also between experimental and numerical modeling. This allows dynamic models of components and subassemblies (regardless if they were determined experimentally or numerically) to be combined with data from existing or newly designed parts in building a "hybrid" total system model that most accurately represents the vehicle. 
Case study: WOCO: From Parts Maker to Solution Provider
Woco Group is an automotive parts supplier which transformed itself into a total solution provider with the help of technology from LMS International. The company was founded in 1956 as a manufacturer of rubber parts such as engine mounts, exhaust hangers, and suspension bushings for vehicles.
 Throughout the 1980s, business was lost to third-world countries where lowwage producers made rubber parts at a fraction of the cost. To differentiate the company, a strategy was developed to leverage their expertise in rubber parts and specialize in supplying OEMs with complete modular systems for quieting sound in automobiles.
Such a move elevates Woco from second to first-tier supplier status, with the company essentially becoming a co-developer of the vehicle and close partner with the automotive OEM. Such a radical expansion for the company hinges on technology, with state-of-theart tools giving engineers the results, measurements, analysis, and simulations needed in leveraging their expertise of vehicle sound and vibration.
Advanced vibration and acoustic testing facilities include equipment for static and dynamic testing, durability analysis, and acoustic holography performed on entire vehicles, subsystems such as engines, and individual components. Testing vehicles and tuning acoustics is performed using measurement and analysis systems from LMS International. The transformation of Woco from parts maker to solutions provider has paid off big for the company, with sales almost tripling since the early 1990s. Major customers include DaimlerChrysler, Ford and Volkswagen in Germany, and Renault and Peugeot in France. Woco also supplies vibro-acoustic solutions to Ford, GM, and DaimlerChrysler facilities in the US.
Woco engineers work closely with those at the OEM throughout vehicle development, from the virtual and conceptual stage of design through prototype testing and pre-production refinement. In many cases, Woco not only develops acoustic and vibration systems for the vehicle but also suggests modifications to the body, chassis, exhaust, and engine designs to optimize the total vehicle configuration.
Woco also closely partners with automakers in developing more efficient production operations, providing
modular subsystems such as gearshift assemblies. In a close partnership with DaimlerChrysler, Woco assembles pedal systems inside the automaker’s Rastatt (Germany) plant and delivers the completed module for just-in-time assembly into cars. Most recently, Woco formed a joint venture company Woco Michelin AVS with the global tire rubberparts producer Michelin for cooperative development of chassis parts. Case study: Heat Up, Cool Down. Behr innovates thermalmanagement solutions with LMS technology
Major car and truck producers increasingly ask suppliers to take on additional levels of engineering responsibility for the parts and assemblies they manufacture. Behr receives more and more requests to design complete modules and entire thermal-management solutions to meet the unique demands of specific vehicles. Air conditioning systems from Behr improve occupant comfort, ergonomics, user-friendliness, safety and total thermal performance of the vehicle. The engine-cooling systems provide a stable, temperature-controlled environment for high-performance engine efficiency, and resulting fuel and emission levels.
Behr’s challenging future
 With the target specifications of the OEM at hand, Behr initiates the task of developing a tailor-made air conditioning and/or engine-cooling system, while facing several challenges. Firstly, the dedicated vehicle space assigned to Behr’s systems is precisely specified and is often very limited, as room must also be reserved for the glove compartment, airbags, engines, actuators, turbo components, etc. Next, the Behr package is held against strict weight limits and outstanding cooling and heating performance characteristics. Then, Behr solutions in operation must meet very tight NVH restrictions to keep overall interior noise levels down. Reliability is another key issue, as the performance of the cooling system is critical to the reliability of the car itself.
Turning smart processes into product innovations
Behr believes that innovative product design starts with innovative development processes. This vision is put
into practice by installing effective and reliable design processes through the introduction of virtual design simulations in all steps of the development. To utilize simulation in the early concept phase, Behr sets up preliminary geometry models and builds the basic system models. Results gained from motion simulations, followed by acoustic simulations and durability assessments, already provide valuable insights into the conceptually-developed system models. This allows Behr to narrow down the scope of successive and extensive simulations in later design phases. At Behr, new products are effectively and accurately designed by finding the right combination of vigorous virtual simulations and test-based validations.
Refining airflow, noise and vibration
 Since silent operation of systems such as air-conditioning is required by car drivers as one of the key values for comfort, OEMs impose ever-more stringent NVH levels on most of their suppliers. Behr anticipated this by performing intensive acoustics and CFD (Computation Fluid Dynamics) studies to further reduce the noise levels and improve the performance of the thermal-management systems. For example, Behr uses parametric cabin models to simulate how the air flow of the systems in operation will be perceived by the passengers in the car. Sources of undesired noises and disturbing vibrations are also traced and different design variations are evaluated to optimize the acoustic transfer functions of air-conditioning systems. Controlling NVH is very complex due to the numerous potential areas of concern, such as the flaps regulating cold and warm airflows, the interconnections between components, as well as the stiffness of the material itself.
Capturing simulation processes
To further strengthen its highly competitive position in its market place, Behr needs to deliver worldclass
thermal-management solutions, which comply with stringent, multi attribute requirements. By re-designing its product development processes by integrating virtual simulations in every process step and by efficiently complementing simulations with physical testing, Behr will achieve these targets. At Behr, virtual prototyping is a standard practice. The company already experiences the leveraging of specialist expertise and the control over the characteristics of products that it will offer in the near future. Early insights and virtual design explorations speed up the design process and deliver heightened degrees of innovation. In the Behr development process of thermalmanagement solutions, the simulation and test solutions from LMS make a big difference.
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