The Reliability Dilemma in Space Program Packaging

<div class="htmlview paragraph">This paper presents the basic test data obtained from tests of a cabin air distribution system in a simulated Space Station U.S. Lab-A module.</div> <div class="htmlview paragraph">The cabin air distribution system controls the flow of air in the open space of a Space Station module. In order to meet crew comfort criteria the local velocities for this cabin air are required to be distributed within a specified range with upper and lower limits. Achieving this desired velocity distribution is dependent upon the: (1.) design of the cabin air supply equipment and cabin air return equipment, (2.) total flowrate of air supplied to and subsequently returned from the cabin, and (3.) interactive effects of any other additional air flow streams which enter and exit the cabin.</div> <div class="htmlview paragraph">The basic Space Station design for the cabin air supply and air return equipment was used in this test program. Only directional adjustments to vanes in supply air diffusers were made during the test. This equipment is included in the Temperature and Humidity Control (THC) subsystem for the Space Station. Two other air streams, in addition to what is defined as THC cabin airflow, which were involved in the test program were:</div> <div class="htmlview paragraph"> <ol class="list nostyle"> <li class="list-item"> <span class="li-label">1.</span> <div class="htmlview paragraph">Standoff airflow – Standoffs are described in the paper. Briefly, they are enclosures within the cabin which formerly included ventilation fans. The consequent standoff airflow interacted with THC cabin airflow. The present baseline THC subsystem does not include the standoff fans.</div></li> <li class="list-item"> <span class="li-label">2.</span> <div class="htmlview paragraph">Intermodule Ventilation (IMV) Airflow – IMV assemblies are used to interchange airflow between Space Station modules. These modules include the U.S. Lab-A module, the nodes, and, later in the Space Station program, the international modules.</div></li></ol></div> <div class="htmlview paragraph">Test results from eight (8) of the test runs which demonstrate the ability for the air distribution system to meet its objectives are presented. These test run results are compared with each other with respect to their standing relative to meeting the test objectives.</div> <div class="htmlview paragraph">The test program investigated the effects of the variables noted above in meeting the test objectives. The basic variable in these test runs was the THC airflow. This airflow varied from 300 cfm to 500 cfm in the 8 test runs presented here. Some changes were made in supply air diffuser vane directional settings. Standoff airflow was used in one test run (number 4) and IMV airflow was used in test runs 5, 6, 7, and 8. Based on the test results, the desired velocity range and an engineering evaluation of the test results, a THC airflow rate for U.S. Lab-A is recommended.</div>

<div class="htmlview paragraph">High power laser technology has been strongly highlighted as a future welding process for the automotive industry, particularly for welding the car body structure. The main reasons are:</div> <div class="htmlview paragraph"> <ul class="list disc"> <li class="list-item"> <div class="htmlview paragraph">Higher tensile and fatigue strength in the welded joint (stronger body)</div> </li> <li class="list-item"> <div class="htmlview paragraph">More stable and improved body tolerances</div> </li> <li class="list-item"> <div class="htmlview paragraph">Higher finish quality</div> </li> <li class="list-item"> <div class="htmlview paragraph">New design potential</div> </li> </ul> </div> <div class="htmlview paragraph">To fully utilise this potential and to minimise the constraints of the laser welding process, there is a need for full-scale application tests. These must be performed within the automotive companies i.e. in the pilot plant.</div> <div class="htmlview paragraph">Technological and production system related risks must be eliminated or minimised prior to series production and this has been done in a short period of time.</div> <div class="htmlview paragraph">For two years now the new Volvo 850 is the only car on the market where the roof is laser welded by using a Pressure Roller Device, PRD. The PRD is used to fix the sheets together during the welding operation. The welding process has been improved and optimised under production conditions.</div>

<div class="htmlview paragraph">The search for improvements in fuel economy, specific power, exhaust emissions and refinement leads to an increasing number of experimental variables and flexibility in their operating strategy. This makes identification of optimum settings and robust solutions more demanding. New test and analysis techniques are required to identify underlying trends and sensitivities in order to determine, with some confidence, the technical and commercial benefits of changes to one or more parameters. Greater emphasis on experimental design will therefore be essential for any engine research and development programme.</div> <div class="htmlview paragraph">Design of experiments (DoE) techniques have been widely used for identifying optimum settings. Traditional experimental designs can be improved by including engineering knowledge more directly into the design process and by providing information on a continuous basis during the test programme.</div> <div class="htmlview paragraph">This paper explores the potential of Bayesian methods in engine Research and Development testing. By employing Bayesian methods, it is possible to define a prior model and update the model as test data become available. This makes it possible to build and interrogate the model earlier in the test programme. The model can then be used to identify the best settings and plan further test work.</div> <div class="htmlview paragraph">Examples are given to illustrate ways for collecting and using the required engineering knowledge, alternative criteria for selecting the test points and some Bayesian analysis tools.</div>

<div class="htmlview paragraph">Cost reduction is an essential and continuous process to meet the competitive environment of product pricing and to increase the profitability of an organization. Integrated cost reduction exercise encompass all the possible avenue., e.g. Alternate material & it's procurement system, batch size, material handling, manufacturing process improvements, logistics and finally review & make changes to derive an optimum design and cost reductions to maximum extent.</div> <div class="htmlview paragraph">This paper presents a systematic approach for achieving the cost reduction of an existing 5.7Tonnne LCV truck frame from design consideration. The methodology involves, identification of the components of the frame for the cost reduction, redesign of existing frame compatible to the cost reduction need, preliminary performance evaluation of the present frame and the cost reduction frame, redesign of the frame for the performance, detailed cost evaluation, prototype manufacturing, laboratory testing, vehicle level testing and final release for the mass production. Chassis designers contributed for major design changes to derive maximum cost reduction without compromising durability or performance deterioration due to bending or torsional stiffness changes from existing frame.</div> <div class="htmlview paragraph">After a comprehensive study, it is identified that deletion of the boxing plate and the replacement of the tubular cross members with channel type cross members will contribute for the potential cost savings of the frame. With these inputs concept design of the cost reduction frame is arrived.</div> <div class="htmlview paragraph">The important performance characteristics of a chassis frame are structural integrity (Strength and Stiffness) and durability. The existing and the cost reduction frames are evaluated based on these performance characteristics.</div> <div class="htmlview paragraph">The final design of the cost reduction frame is arrived based on CAE analysis of the frame for structural integrity, Number of iterative operations got eliminated due to the use of multidisciplinary optimization (MDO) package. Different load cases which focus on strength and stiffness of the frame are considered as an example.</div> <div class="htmlview paragraph">Bending and torsional stiffness of the existing and the cost reduction frames are also measured in the test rig. It is found that bending stiffness of the cost reduction frame is 9.15% more than the existing frame and torsional stiffness of the cost reduction frame is closer to the existing frame. It was also found that the durability of the existing and the cost reduction frame in bending is almost same. The test specifications are arrived based on strain measurements on the existing frame in our torture track.</div> <div class="htmlview paragraph">The above methodology helped us in deriving a estimated cost saving of Rs.311/- by the modified frame design. There are other intangible benefits like savings in labour cost due to elimination of the boxing plate, savings in the processing cost of boxing plate welding etc. The estimated cost savings is likely to be double of the above amount and would result in 3.5% of the Chassis frame aggregate cost.</div>

<div class="htmlview paragraph">Rapid wearing out of the engines of farm tractors, trucks and automobiles led the University of California to undertake a study of the dust problem and the efficiency of air-cleaners in removing field and road dust from the air before it passes into the engine. Work was begun in 1922 and several reports have been made on the methods devised and the progress made during the last 2 years. Results to June, 1924, were given in the paper published in August, 1924. The present paper gives results of the studies to the end of 1924 and includes data from tests of 12 new makes or models of air-cleaner not previously tested or not fully tested.</div> <div class="htmlview paragraph">Of outstanding importance is the discovery that the quantity of dust inspired by any cleaner or carbureter is greatly reduced if the intake is placed high and faces away from the direction of motion of the vehicle. The cleaners on two 3½-ton Liberty trucks used in road construction work in California, with intakes located 46 and 48 in. above ground and facing forward, encountered approximately 0.07 and 0.08 grams of dust per mile respectively, whereas two other trucks of the same make and model and used in the same work, which had no air-cleaners but whose intakes were directed backward, evidently encountered much less dust as the average engine wear in these two trucks was almost exactly the same as in the truck fitted with a cleaner that caught and held slightly more than 0.08 grams per mile but which probably passed as much dust into the engine as it caught and held. A 1-ton truck which had its intake located 47 in. from the ground and facing sidewise under the hood encountered slightly more than 0.001 grams of dust. This truck, however, was used mainly on paved roads.</div> <div class="htmlview paragraph">The makes and models of cleaner tested since the last progress report was given at the Spring Lake Meeting of the Society last June are illustrated and described and the author presents graphs showing the efficiency of all the devices tested and the amount of restriction they imposed on the flow of air to the carbureter when clean and when they had been fed from 25 to 100 grams of No. 1 standard dust, which is entirely free from moisture, has a specific gravity of 0.680, and 98.60 per cent of which passes through a screen of 200 meshes per in.</div> <div class="htmlview paragraph">The accompanying tables give the type, weight, material and dimensions of the 12 additional cleaners tested since June, 1924, the results obtained in service tests to determine the quantity of dust entering the carbureter intake, a summary of results of tests of the 12 cleaners showing their efficiency in service runs and the amount of restriction caused by each cleaner as measured in inches of water due to vacuum in a U-tube manometer, and results of a fill-up test of these cleaners to give a general indication of how a cleaner might act if subjected to gross neglect and abuse by determining how much or how little increase of restriction occurs when from 1 to 10 lb. of No. 2 standard dust has been fed to it.</div> <div class="htmlview paragraph">Other tests of great importance which might be made would have as their objects the determination of length of time the cleaner will last in normal service, how long it will function without attention, amount of work or time required to keep it clean and in proper working condition, weak places in its construction and variation in efficiency among cleaners of the same make and model.</div> <div class="htmlview paragraph">The University of California is preparing a program of laboratory tests of bearing wear, which is closely allied with the dust problem. The author says that the function of the University is not to do routine testing but to devise methods and prove them by their practical application. It is ready to undertake the task in cases where the regular test methods are not applicable, as in testing radiator-fan-type cleaners.-</div>

<div class="htmlview paragraph">Lean burn spark-ignition engines (S.I.E) are currently under scrutiny for their fuel economy and pollution reduction potential while using fuels with ordinary anti-knock quality.</div> <div class="htmlview paragraph">This study was concentrated on turbulence generation in a simulated inlet manifold of S.I.E. via the use of several designs of turbulence generators. A special test set-up was specifically designed and built for this study, and special measuring probes were constructed, developed and calibrated to find out the turbulence level behind each turbulence generator. Four types of swirl and turbulence generators were used and tested to find out the optimum design and operational parameters.</div> <div class="htmlview paragraph">The investigation has been carried out using air as the working medium, while the effect of flow velocity, temperature and turbulence generator design parameters were studied and their effect on the relative turbulence kinetic energy was experimentally found out. Also the decay in turbulence level in the inlet manifold was measured as well as the effect of air to fuel ratio and the existence of bends downstream the generator. Correlations were developed for each type of turbulence generators to predict the level of turbulence as well as the turbulence decay with distance. The optimum type of turbulence generators was put forward and optimum design parameters for the generator were found out.</div> <div class="htmlview paragraph">Based on the results of this study it can be concluded that replacing the conventional throttle valve of the engine by two turbulence generators in series (disc type of delta-wing type) may be the optimum way to achieve a high turbulence level and a high volumetric efficiency.</div>

<div class="section abstract"><div class="htmlview paragraph">AEA Technology is carrying out an ongoing programme of lightning simulation testing work on carbon composite ‘T-joints’. These typically represent skin to spar bolted interfaces, and the tests help to determine whether aircraft fuel tanks incorporating such structures are liable to produce sparks during a lightning attachment.</div><div class="htmlview paragraph">For testing, the T-joints are integrated into a complex test rig that is intended to provide representative current flow during the simulation tests. The intention is that the current distribution in the T-joint should be similar to the current distribution on the equivalent part of the aircraft structure during a lightning attachment.</div><div class="htmlview paragraph">A combined experimental testing and computational modelling work programme has been carried out in order to investigate how representative the test-rig current distribution is to that on a real aircraft. In the first part of this study the test rig itself is modelled using the 3D code ELECTRA. This is a mesh network code which solves Maxwell’s equations in the low frequency domain, and which has already undergone validation for some lightning applications. The predictions of current distribution from ELECTRA are compared with the experimental measurements. The exercise is carried out both for all-metallic components, and for carbon composite components. The good correlation obtained between the prediction and measurement provides further confidence in the use of the code.</div><div class="htmlview paragraph">Following this validation exercise a model is created of a lightning attachment to the skin of a composite wing box in order to determine the current distribution in the skin, spars and ribs. In this way a comparison between an inflight lightning strike current distribution and that achieved in the test rig can be compared.</div><div class="htmlview paragraph">This programme of work has been funded by the UK Defence Procurement Agency.</div></div>

<div class="section abstract"><div class="htmlview paragraph">In the pursuit of carbon emission reduction, hybridization has emerged as a significant trend in powertrain electrification. As a crucial aspect of hybrid powertrain system development, achieving high brake thermal efficiency (BTE) and a wide operating range with high efficiency are essential for hybrid engines to effectively integrate with the hybrid system.</div><div class="htmlview paragraph">When developing dedicated hybrid engines (DHE), several design considerations come into play. First, in order to make efficient use of available resources and enable engine production on the same assembly line as conventional engines, it is crucial to maintain consistency in key design parameters of the cylinder head and block, thus extending the platform-based design approach. Among the key measures to achieve high BTE, cooled exhaust gas recirculation (EGR) has been extensively explored and proven effective in improving efficiency by mitigating knocking and reducing engine cooling heat loss. Fast combustion, acting as a facilitator, becomes crucial for the system to handle high EGR rates. Therefore, a high-tumble combustion system design is required as an integral part of the hybrid engine to promote rapid combustion.</div><div class="htmlview paragraph">Optimizing the gas exchange system is another crucial aspect in achieving high brake thermal efficiency. Investigation results indicate that through system optimization and trade-offs, optimal matches can be found among EGR rate, cam duration, and compression ratio for a hybrid engine. Furthermore, by optimizing energy management strategy with the hybrid system, the engine operates under high-efficiency regions for the majority of the WLTC test cycle, resulting in reduced fuel consumption.</div><div class="htmlview paragraph">This paper describes the evolution of combustion system design from conventional engines to DHE at SAIC Motor, and presents investigations into the impact of key technical measures on brake thermal efficiency. It also explores the optimization of energy management strategies and their effect on engine operating conditions and fuel consumption of the hybrid vehicle in the WLTC cycle.</div></div>

<div class="htmlview paragraph">Side impact occupant safety has been evaluated and optimized using a MADYMO vehicle compartment model with prescribed structural motion. A CPU efficient approach is presented where reliability is optimized in three stages: <ul class="list disc"> <li class="list-item"> <div class="htmlview paragraph">Stochastic (random) analysis to calculate the scatter that could be expected for the initial design</div></li> <li class="list-item"> <div class="htmlview paragraph">Optimization taking scatter into account by safety margins derived from the first stage</div></li> <li class="list-item"> <div class="htmlview paragraph">Robustness verification</div></li></ul></div> <div class="htmlview paragraph">To evaluate scatter resulting from dummy hardware variations a stochastic model of the ES-2 dummy was used. Variation of dummy & seat position and variation of airbag and door trim properties were included using the scatter database developed in the EC projects VITES and APROSYS.</div> <div class="htmlview paragraph">Two sets of 150 simulations were used for the scatter analysis (including 23 scatter parameters) and 120 simulations were necessary in the optimization (including 3 design parameters). The CPU per analysis was 2 hours and the total process took 9 days using up to 6 processors. These numbers prove that this method can be used in a vehicle development process. In this project the EuroNCAP side impact sub-score has been evaluated. The initial stochastic analysis showed results ranging from 3-5 stars where in particular the parameters related to dummy and seat position have a major influence. The optimization showed results ranging from 4-5 stars, with an increased probability of obtaining 5 stars.</div>

<div class="htmlview paragraph">This paper presents several methods for reducing engine weight primarily through substitution with light-weight materials. The efficiency and performance of the engine were reviewed using a light-weight experimental engine (hereinafter called “weight-reduced engine”) constructed by the authors in order to investigate the possibility of practical use of the proposed weight reduction measures.</div> <div class="htmlview paragraph">The weight-reduced engine is based on an in-line 4-cylinder, 2.0 liter, gasoline engine with the base engine weight of 162 kg excluding engine oil and coolant and was reduced by 37 kg by applying alternative light-weight materiaLs and new manufacturing techniques. This corresponds to 23 % weight reduction.</div> <div class="htmlview paragraph">The materials used in the weight-reduced engine are 53 % steel, 33 % aluminum, 7 % plastics and 7 % other light-weight materials.</div> <div class="htmlview paragraph">It was found that by application of light-weight materials, the engine performance of the weight-reduced engine could be improved. That is improvements in response and friction loss. In particular, weight reduction of the major moving components, such as connecting rods, not only contributes to reduce friction loss but leads to a weight reduction for other components.</div> <div class="htmlview paragraph">The light-weight components have been put to various kind of testings which cover fatigue of components and bench testing with assembled engine by motoring and firing. These results were sufficient to confirm that these components are durable enough to operate in a practical environment.</div>

<div class="section abstract"> <div class="htmlview paragraph">This specification defines test methods and performance criteria for evaluating ultrasonically welded wire-to-terminal metallurgical bonds. The examples used are specific to the linear weld type of process equipment. USCAR-38 is not applicable for “Splice Welding”. The specification is applicable to wire-on-pad configurations with a typical weld shown in <span class="xref">Figure 1</span>. This test specification subjects parts under test to environmental exposures to simulate a lifetime of field exposure for a road vehicle. Exposures called-out in this specification include Thermal Shock, Temperature Humidity Cycling and mechanical abuse. This test specification is intended to evaluate the strength and performance of the interface between wires to an electrical terminal. Validation of the performance of the Terminal is a separate task and can be accomplished using a component validation test such as SAE/USCAR-2, which evaluates whether the entire connection system is acceptable.</div> <div class="htmlview paragraph">If the weld under test (WUT) is different than described in this section, or is subjected to conditions beyond what is typical of automotive use, the SAE/USCAR-38 test sequence may not be applicable. Parts used in custom applications must pass tests simulating the actual conditions encountered before they can be considered acceptable for that application.</div> <div class="htmlview paragraph">Vehicle and product conditions applicable to use of this specification are:</div> <ol class="list nostyle"> <li class="list-item"> <span class="li-label">1)</span> <div class="htmlview paragraph">Applicable use: This specification is applicable where the wire and terminal are part of an electrical connection system used in road vehicles at ambient temperatures from -40°C to +150°C. Applied voltage may be either low (0 - 60 VDC) or high (to 600V). USCAR-38 applies to all wire lengths and includes a special test for wires shorter than 500mm where a weld is done after another component has been assembled to the wire (test samples must be made from the exact production-intent welding process to assess potential process damage risk to the terminal at the other end of the wire. Wire harness makers typically will be given the responsibility to track short wire applications per a statement in the applicable engineering statement of work.</div></li> <li class="list-item"> <span class="li-label">2)</span> <div class="htmlview paragraph">Applicable designs: The procedures described are applicable to buss, terminal, or device connections, including eyelet and battery terminations comprising either single or multiple wire terminations. Designs withd without crimped insulation wings are applicable.</div></li> <li class="list-item"> <span class="li-label">3)</span> <div class="htmlview paragraph">Applicable wire: This specification was developed using clean, bare, uncoated, stranded automotive wire. Wire with tin coatings, applied lubricants, or contamination is known to affect the mechanical and electrical performance of ultrasonically welded cable terminations and are not applicable to be evaluated per this spec.</div></li> <li class="list-item"> <span class="li-label">4)</span> <div class="htmlview paragraph">Applicable wire sizes: Copper wire sizes between 0.22mm<sup>2</sup> to 85mm<sup>2</sup> per ISO 6722-1 wire specification and aluminum (per ISO 6722-2) sizes from 0.5mm<sup>2</sup> to 120mm<sup>2</sup> are applicable. Other wire types may be tested per this specification but cannot claim compliance to this specification since those sizes are out of our experience. Examples of representative “other” wires types are: compressed core, compacted core, solid wire core, and wire core materials other than copper, copper alloy, aluminum, or aluminum alloy. Examples of different center core materials are copper-clad or steel-center-core wires.</div></li> <li class="list-item"> <span class="li-label">5)</span> <div class="htmlview paragraph">The validation process described applies only to linear ultrasonic welding, typically with pressure, energy, and amplitude set as inputs and weld time controlled by limiting energy based on ‘feedback’ from process monitoring sensors. Using process feedback assures the energy-per-weld is maintained. If the equipment used to make samples for USCAR-38 testing is different from this description, this spec may need to be modified or may not be applicable.</div></li></ol> </div>

<div class="htmlview paragraph">A variety of mechanical head forms is used today in the evaluation of the crashworthiness of automotive interiors and the effectiveness of helmet designs. Most head forms are of a very rigid metallic construction, although frangible head forms that indicate skull fracture are presently available. None of the existing head forms can be considered a complete mechanical analog to the human head in terms of mechanical response. This paper describes the initial phases of the development of such a head form.</div> <div class="htmlview paragraph">The first step in the development of the model was the determination of the pertinent mechanical properties of the tissues of the human head (scalp, skull bone, dura mater, and brain). A testing program which determined these properties at both static and dynamic strain rates is described and the results are summarized.</div> <div class="htmlview paragraph">The second phase of the program was to find and develop synthetic materials which duplicated the mechanical properties of the human tissues. Many materials were investigated, and modifications to existing materials were made. The synthetic materials were tested by the same methods used in the human tissue tests. Results comparing the synthetic materials with their human tissue counterparts are given.</div> <div class="htmlview paragraph">Proposed simple precursor models are described, and a discussion of future, more complex models is given, along with the specific types of head injury phenomena that the model will be required to simulate.</div>

<div class="section abstract"><div class="htmlview paragraph">As the emissions and fuel economy standards for internal combustion engines become ever more stringent, a variety of valvetrain control methods have been developed to improve engine performance. One of these is camshaft (CAM) phasing, which controls the angular position of the CAM relative to the crankshaft allowing changes to the timing of valve lift events. This method has demonstrated advantages including broadening the engine torque curve, increasing peak power at higher RPM, reducing hydrocarbon and NOx emissions, and improving fuel economy. In addition, external EGR systems can be eliminated because internal cylinder dilution control can be achieved by varying CAM timing.</div><div class="htmlview paragraph">Current implementations of CAM phasing use oil-pressure-based electro-mechanical systems. While these systems are relatively low cost and have proven to be robust, they have disadvantages at low oil temperatures and pressures (such as during cranking events). To overcome performance issues of oil based systems, Delphi has created a CAM phasing system using a brushless DC (BLDC) motor to drive the phasing mechanism. This approach provides full control independent of oil conditions and demonstrates increased phasing authority.</div><div class="htmlview paragraph">This paper will describe the electronics and algorithms required to control the three-phase BLDC motor which is part of the electric variable CAM phasing (eVCP) system. This controller takes desired CAM phase angle as an input, calculates the phase angle error, and closes the loop on the resultant motor current command. The electronics are packaged in a production-style case suitable for use in customer development applications.</div><div class="htmlview paragraph">From a software perspective, this paper will discuss architecture considerations, including provisions for model-based rapid algorithm development and low-level motor control functions. Hardware component selection criteria and electromagnetic compatibility (EMC) design considerations will also be included. Finally, motor performance test data will be presented.</div></div>

<div class="htmlview paragraph">In comparison with current production diesel engines the next generation will need to have better fuel consumption, lower noise and reduced emissions both gaseous and visible.</div> <div class="htmlview paragraph">Research over the last ten years has shown that higher rates of injection, coupled with a sharp end of injection and precise timing control will give considerable benefits.</div> <div class="htmlview paragraph">The Lucas CAV response to this requirement is the development of an electronically controlled unit injector system which provides these characteristics.</div> <div class="htmlview paragraph">This paper describes the operating principles and looks at the main performance parameters, including design considerations for continuous operation at pressures up to 1500 Bar.</div> <div class="htmlview paragraph">As the unit injector is a new concept to many engine manufacturers, Lucas CAV has developed a suite of computer programmes to assist in the design and engine application process in terms of a complete hydraulic simulation, unit injector drive train analysis and cam design.</div>

<div class="htmlview paragraph">A continuously growing demand comes from the automotive industry for optimization of materials and sound insulating product packaging inside the car, so as to propose the best acoustic performance at reduced costs.</div> <div class="htmlview paragraph">A new acoustical holography system provides part of the solution to meet such a demand. The capability of measuring the acoustic field inside a vehicle with high spatial resolution makes it an advanced tool for performing extensive studies of the acoustic transparency of car openings and interior components in various environmental conditions (acoustic chamber, on road, in wind tunnel). The method allows for:</div> <div class="htmlview paragraph"> <ul class="list disc"> <li class="list-item"><div class="htmlview paragraph">Detailed localization of noise sources or leaks,</div></li> <li class="list-item"><div class="htmlview paragraph">Knowledge of the acoustic energy distribution on elementary surfaces (such as doors, windscreen, roof, sealing components, …),</div></li> <li class="list-item"><div class="htmlview paragraph">Reconstruction of the energy radiated by elementary surfaces in order to predict the acoustic pressure at driver's and passengers' ears,</div></li> <li class="list-item"><div class="htmlview paragraph">Introduction of local modifications on subsystems and components in order to predict their effect on the acoustic field.</div></li> </ul> </div> <div class="htmlview paragraph">In conjunction with some numerical prediction methods, this technique will allow to apply integrated acoustic engineering design methods for a complete understanding and control of the large variety of components and systems involved in the car performance.</div>