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A new test method, Current Decay, has been developed which aids in the early detection and removal of premature light source failures. These failures, whether mechanical or developmental, can go undetected until later processes where the severity of a failure has increased. The Current Decay test method provides the lamp assembly manufacture a repeatable and more accurate method to perform the light-up verification of the lamp assemblies’ bulbs. Traditional light-up techniques are deficient in detecting certain failure modes including their various failure degrees. Especially when the light sources, bulbs, are inside the lamp assemblies making it difficult for an operator to notice the defect.

In this paper, a CAE (Computer-Aided Engineering) methodology to simulate the vibration test and predict fatigue life of head lamp bulb shield is presented. A modal analysis is performed first to determine the critical elements from the strain energy density distribution patterns. A random vibration frequency response analysis is then performed to monitor the stress response power spectral densities (PSDs) for critical elements due to the g-load input PSDs, measured at the mounting point in all three directions. Fatigue life can be estimated based on the stress response PSDs and material S-N curve by using Dirlik's method. The fundamentals for frequency domain fatigue analysis are reviewed and a case study with test correlation is then presented.

A stamping process window is a set of ranges of the critical input variables in the process. Quality parts can be produced only if all of these variables fall within their respective ranges. To achieve this, the window has to be wide enough and the process properly located within the window. In this paper, various input variables in stamping are examined and the variables that have to be strictly controlled are identified. The establishment, transfer, adjustment, protection, deterioration and re-opening of stamping process windows are described. Examples from production are presented.

Cost effective instrument panel design and development techniques were employed on the 1999 Audi TT sports vehicle, reducing the piece cost and enhancing performance. Technical solutions demonstrated include improved foam adhesion, eliminating the use of primer; thin wall injection molding technology, reducing the weight of the plastic retainer; heat aged performance improvement, reducing the cost of poor quality; as well as innovative development methods which reduce the total program costs. These development methods include the validation of a hidden air bag door design, which incorporates a thin wall retainer molding with integral plastic halo surround. The thinner wall helped Audi engineers reduce the weight of the part, adding to vehicle performance. Air bag system validation costs were also streamlined with the use of high frequency data acquisition in coordination with dynamic analysis simulations of the event.

Using a combination of engineering test experience, explicit finite-element analysis, and advanced materials characterization, a predictive engineering method has been developed that can assist in the development of active top pads. An active top pad is the component of the instrument panel that covers the passenger airbag module and articulates during a crash event, allowing the airbag to deploy. This paper highlights the predictive analysis method, analytical results interpretation, and suggestions for future development.

In a joint effort between Ford Motor Company, Visteon Automotive Systems, Textron Automotive Company, and Dow Automotive the 1999 Mercury Cougar instrument panel (IP) was designed and engineered to reduce the weight and overall cost of the IP system. The original IP architecture changed from a traditional design that relied heavily upon the steel structure to absorb and dissipate unbelted occupant energy during frontal collisions to a hybrid design that utilizes both plastic and steel to manage energy. This design approach further reduced IP system weight by 1.88 Kg and yielded significant system cost savings. The hybrid instrument panel architecture in the Cougar utilizes a steel cross car beam coupled to steel energy absorbing brackets and a ductile thermoplastic substrate. The glove box assembly and the driver knee bolster are double shell injection molded structures that incorporate molded-in ribs for added stiffness.

With parts consolidation and increasing systems performance requirements, instrument panel systems have become increasingly complex. For these systems, the use of predictive engineering tools can often reduce development time and cost. This paper outlines the use of such tools to support the design and development of an instrument panel (IP) system. Full-scale test results (NVH, head impact, etc.) of this recently introduced IP system were compared with predicted values. Additionally, results from moldfilling analysis and manufacturing simulation are also provided.

Moisture inside automotive lamps is universally accepted as a performance and cosmetic problem, particularly in the newer clear lens lamps. While simple open venting systems (tube type) can prevent liquid water intrusion, water vapor cannot be easily excluded from the lamp interior. Thus, under certain unavoidable conditions involving changes in environmental temperature, humidity, and lamp operation, a lamp may produce undesirable condensation on some interior surfaces. Efforts to optimize venting systems to clear this condensation involve controlling the air exchange through the vents. This air exchange is highly affected by outside airflow, a parameter complicated by wind, vehicle motion, and structures around the lamp. In this paper we report on investigations regarding how airflow around a lamp, both free and hindered by surrounding structures, affects the ability of common venting strategies to clear internal moisture.

Many engineers today use large, powerful multi-purpose test systems to do squeak & rattle testing of modules and subsystems such as Instrument Panels, Consoles and Seat Assemblies. Such test systems include Multi-Axis Hydraulic Shaker Tables and Electrodynamic Vibration Systems with large head expanders and rigid (or at least stiff) fixtures. These test systems have been successful when used for squeak & rattle test programs, have been validated as approved test methods, and have become the standards of comparison in many labs today. They are, however, expensive and throughput can be limited due to the time needed to unbolt, unload, handle, load, and re-bolt a test item at its many attachment points on the rigid fixture. Furthermore, the capital cost of these Legacy systems can be prohibitive, especially for the smaller supplier, who is being compelled to perform squeak & rattle testing on the products they supply to their customers, the vehicle manufacturers and Tier 1 suppliers.

Vented automotive lamps exchange moisture with the surroundings during steady state and transient conditions. An application of Fick's Law of Diffusion gives the mass transfer rate of a vapor A through a stagnant column of gas B for steady-state conditions. Automotive lamp ventilation is similar to this simplified problem given certain assumptions and where the vapor A represents moisture in the air at one end of the vent tube and the gas B is the air in or outside the lamp. This paper shows that the equimolar counter-diffusion problem, a solution for Fick's Law, has potential in reliably predicting humidity changes within an automotive lamp for static conditions.

By inner pressure hydroforming a great variety of parts can be produced. This is especially true when forming tubes in a single action press with high closing forces. In cooperation with industrial companies at the Institute for Metal Forming Technology of the University of Stuttgart, Germany, a new concept for presses specially designed for hydroforming tubes and extrusions was developed. The press has a capacity of a 3500 tons closing force and a press table size of 2500 mm × 900 mm. A great reduction in costs can be achieved by integrating spacers between the frame of the press and the ram. This paper introduces this new press and discusses different press concepts for hydroforming tubes and extrusions.

Tailored Blank applications have become more and more important for the advanced light weight and cost effective steel automobile body. During the last decade, the production of Tailored Blanks with a straight weldline has been constantly increasing because their technical and economical advantages are well accepted by automobile manufacturers /1, 2, 3, 4/. But, now the body engineers prefer to have an even more flexible product with specific weldline design, according to the engineering design needs. Thyssen Krupp Stahl AG reacted quickly on this demand and now offers the new product called, Thyssen Engineered Blanks (TEB®s), which meets almost all the needs for the design of components concerning weld-line geometry and weld-line positioning. With our new production line, both single and multiple steel sheets can now be joined together with linear weld-lines, angled weld-lines and curved laser beam weld-lines, Figure 1.

Tailor-welded blanks (TWB) have been increasingly used in the automotive industry as an effective way to reduce weight and costs. Although some of the joining processes for TWB are relatively well known, little independent information exists regarding welding procedure effects on weld/HAZ properties, particularly their effects on form-ability and structural performance under various conditions. In this paper, advanced computational modeling techniques were used to investigate the effects of welding procedures on weld property evolution and its impact on the formability issues. Two case studies were presented. One is on TIG welding of 6000 series aluminum tailored blanks, where thermomechanical effects on weldability was analyzed. Its implication on weld performance during forming will be discussed. The other case is on laser-beam welding of high strength steel to mild steel with a non-linear weld. The detailed thermal history and residual stress development will be presented.

Tailor welded blanks offer a unique opportunity to reduce manufacturing costs, decrease vehicle weight, and improve the quality of stampings through the consolidation of multiple formed, then welded, parts into a single stamping. However, tearing near the weld line often occurs in this type of blank when formed with a traditional deep drawing process. Therefore, some adaptation to the existing sheet metal forming process must be developed in order to reap the numerous benefits available from tailor welded blanks. In this paper, numerical simulation are presented for a newly contrived tailor welded blank forming process where several hydraulic mechanisms apply distinct clamping forces along the weld line during forming. Excellent results demonstrate the effectiveness of the proposed method.

Mill oils and prelubes are applied by the steel producer to prevent corrosion and to enhance formability. During coiling, shipping, and storage the lubricant migrates due to pressure and gravity. The redistribution of the lubricant results in widely varying lubricant weights. The move to reduce and eliminate press-applied lubricants has lead to concerns that the variation in lubricant weight as a result of this migration would adversely affect press performance. The Drawbead Simulator (DBS) and Twist Compression Test (TCT) were used to evaluate friction response of electrogalvanized and galvanneal sheet to varying lubricant weight. Results showed the electrogalvanized sheet was sensitive to lubricant type while the galvanneal sheet was sensitive to the amount of lubricant.

In deep drawing and drawing of car-body parts the friction conditions have a great influence on process limits, on the robustness of the production process and on the quality of the produced parts. Beside the used lubricant, the friction conditions are influenced by the topography of the sheet metal surface and of the tool surface. Therefore the roughness of these surfaces has to be measured. It is well established to measure the roughness of sheet metal surfaces with a stylus device. But more and more optical measurement techniques are upcomming. There are for example instruments on the market which can characterize the roughness profile along a line with an infra-red laser beam. Doing this for parallel lines the topography can be plotted in three dimensions. The disadvantage of all those systems is that the samples to be measured have to be cut from the sheet or from the coil and that is not possible to measure directly the surface of heavy forming tools.

Drawing is the most important operation in stamping. Shut height has been used as the main control parameter in die setup. But shut height control can not provide a consistent binder force for a drawing operation in a double-action press and often produces formability and/or quality problems. This paper will examine how different input variables will affect the performance of a drawing operation in a double-action press. Three examples of using tonnage control and process optimization are provided in improving part quality and reducing down time and scrap cost.

This paper deals with the radii of draw dies for sheet metal parts, like fenders, hoods, and doors. For relative flat parts, like hoods, it is important to get at least a 2% forming rate in the middle of the part to reach minimum of stiffness, work hardening, and sufficient geometric accuracy. This can be influenced by the punch radii. Therefore, optimal punch radii should be known. First experimental results about optimal punch radii where published by J.L. Duncan and B.S. Shabel in the SAE-Paper No. 780391. At the Institute for Metal Forming Technology of the University of Stuttgart, Germany, a “Modified Duncan Shabel Test” (MDS-Test) has been developed. This test makes it possible to investigate not only the punch radii but also the die radii. This paper shows optimal punch and die radii as a function of sheet metal, sheet thickness, as well as of the die material.

Toyota Motor Corporation has developed a new four-speed automatic transaxle U140E named “Super ECT”. The U140E has achieved compactness which enables it to mount on many new platforms, achieved high efficiency, which contributes to improve fuel economy, and it achieved good shift feeling, response, and reduce noise. This paper shows the major features and performance of the U140E.

A prediction technique for the lubricating oil temperature in a manual transaxle was developed. Using this technique, the effects of heat transfer enhancement and heat generation decrease, etc., on the oil temperature reduction can be estimated. The heat generation in a manual transaxle is caused by lubricating oil stirring, friction and gear meshing. The heat transfer and flow characteristics are thus very complicated under the two-phase flow of the oil and air induced by rotating gears. It is necessary for the development of the prediction technique to model the heat transfer process in a manual transaxle. The experiments measuring of heat generation, heat flux and the air flow velocity distribution around the manual transaxle were conducted to get information for modeling the heat transfer process. A flow visualization of two-phase flow in the manual transaxle was also conducted.