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The objective of this paper is to discuss the process, from design conception through analytical simulation to experimental test, of the development of a composite cross car beam for a passenger vehicle application. Over the past five years there has been considerable interest in the development of cross car beams, which serve as the main component for support of the Instrument Panel (I/P) structure and related systems. Stringent design requirements for vehicle Noise, Vibration and Harshness (NVH), durability and crashworthiness have driven the role of cross car beams to new levels. In addition, new styling trends, such as cabin forward design, and new vehicle manufacturing and assembly methods, such as cockpit build, have also placed demands on the role of cross car beams.

The blow molded knee bolsters on the 1996 Chevrolet Astro and GMC Safari vans are the first blow molded parts used on an interior structural application. These knee bolsters also meet FMVSS 208 requirements. The one-piece bolsters, used on both the driver's and passenger's sides of the vehicle reduced cost by $4.00 and weight by 40% per vehicle compared with two-piece, steel-reinforced plastic knee bolsters. Additional savings were realized in tooling cost reductions of $300,000 and a development time that was shortened by 64 weeks. Part testing was also reduced to the tunability of the process. Aesthetic concerns of matching adjacent injection molded and vinyl parts were also met. This paper discusses the combination of material, processing and tooling technologies that made this program a success.

An open vehicle architecture can be achieved by adding a knee cushion to the airbag system. However, a separate knee cushion adds considerable system complexity and cost. A low cost effective solution can be achieved by incorporating the knee cushion into a low mounted passenger side airbag system (LMPAB). The LMPAB incorporates the upper torso cushion and knee bag chamber into a single cushion assembly. This system replaces the conventional knee bolster and knee bolster brackets, allowing passenger side instrument panel surface to move forward in the vehicle. The LMPAB system provides greater styling flexibility and interior space while maintaining the safety of more conventional airbag systems.

Traditional knee bolster designs consist of a first-surface plastic component covered by paint or vinyl skin and foam, with a subsurface steel plate that transfers knee loads to 2 steel crush brackets. The design was developed to meet FMVSS 208 and OEM requirements. More recently, technological developments have allowed for the steel plate to be replaced by a ribbed plastic structure, which offers cost and weight savings to the instrument panel system. However, it is still a hybrid system that combines plastic with the 2 steel crush brackets. This paper will detail the development of an all-plastic design, which consolidates the plastic ribbed reinforcement plate with the 2 steel crush cans in a single engineering thermoplastic component. The new system is expected to offer further cost and weight savings.

Closed loop engineering methods are presented which demonstrate the design of an instrument panel retainer for optimal system performance characteristics such as NVH (noise, vibration, and harshness) and component integrity during crash. These methods incorporate finite element analysis techniques in concert with data acquisition of component and systems test to provide a closed loop analysis to test correlation of performance. Upon validation of the instrument panel systems model for a specific performance attribute, options to improve the system performance or reduce the cost may be reviewed analytically, replacing the historical “cut and test” method. Furthermore, the manufacturing process definition for the retainer is developed concurrent with the plastic part design. Manufacturing analysis methods are used to determine material flow, part cooling, part shrinkage, and ultimately, retainer fit and finish profile.

There is discussion about some aspects of shell calibration in the report. Shell shape errors by calibration without impact are estimated. Calculation algorithm of optimal impact velocity and minimal error of shell size is offered for any combination of shell and die materials. Results of this algorithm usage are presented.

A galvannealed steel sheet (GA) with a Ni-base inorganic lubricant film has been developed to meet the needs of the automotive industry, especially for improved press formability. This paper describes the results of tests performed to evaluate formability, spot weldability, phosphatability, paintability and corrosion resistance of the GA with the Ni-base lubricant film. The coefficient of friction as measured by flat sliding test decreases with increasing Ni content in the lubricant film. The spot weldability evaluated by electrode tip life test is slightly improved after the application of the lubricant film. Phosphatability, paintability and corrosion resistance of the GA with the lubricant film are equivalent to those of GA without the lubricant film.

An experiment to determine the effects of mill oil weight, phosphate coating type and weight, surface roughness, and blank wash on the formability of prephosphated galvannealed steel was conducted. Limiting dome height, limiting drawing ratio and draw bead simulator friction tests were run on bare galvannealed and galvannealed coated with a conventional process phosphate and with three Dried-in-Place (DIP) phosphate products. Formability performance of both the conventional and DIP phosphate coated products was significantly better than that of oil-only coated galvannealed steel. Phosphate coating weights heavier than about 0.6 g/m2 per side did not significantly improve formability. The formability improvement from phosphate coating was about equal for the four products tested, with optimum oil weight for formability in the 1.3 to 1.9 g/m2 range. Surface roughness (within the testing range) and blank washing had no significant effects on formability.

The present research is concerned with the quality of the shearing process, which is an integral part of automotive vehicle body stamping. Experiments were done to analyse the influence of the gap between the cutting edges and the geometry of the cutting blades, on the quality of the sheared surface. Experimental results are presented as microstructures of polished samples. To predict the quality of sheared surfaces, a numerical code based on solid mechanics equations, elastoplastic flow theory and cummulative theory of damages was created.

Continuing pressure to meet fuel economy and safety requirements, improve quality and minimize cost has resulted in new challenges for auto industry engineers. New sheet metals for auto body stampings have helped the transportation industry meet these challenges. The steel industry has developed a number of new products for these purposes, including dent resistant steels for outer body panels, high strength steels for structural applications and interstitial free (IF) steels for difficult forming challenges. The aluminum industry is also aggressively pursuing new applications. New aluminum products have been applied to closure panels, resulting in significant mass reductions in several high volume vehicles. Stamped aluminum for structures have also been developed and commercialized, albeit for lower volume production. This paper will discuss these new materials and the benefits and challenges they present.

The ultimate aim of applied research is the generation of knowledge relevant to production processes. A vital first step in acquiring such knowledge is the choice of experimental methodology. There are innumerable test methods developed specially for exploring the tribology of sheet metalworking; the purpose of this paper is to examine the major classes of test methods for their applicability to the most important sheet metalworking processes. A distinction is made between simulation and bench tests. When viewed critically, many so-called simulation tests are, in fact, bench tests. They may well be suitable for generating basic information but, for transfer of results to applications, require a knowledge of the lubrication mechanisms active in both test and process.

Minimization of part variation has been a challenging topic for both researchers and engineers. Variations in final stamping parts could come from numerous sources such as incoming material, lubricant, processing parameters, environment, automation, etc. Identifying the cause of the variations is not only time consuming, but also a continuously changing process. In this paper, experiments are reviewed which were conducted to examine the feasibility of implementing closed-loop process control to reduce dimensional variations on an in-production 3D part. Specifically, the effects of punch force (PF) and binder force (BF) on part dimensions are studied. For our particular application, proper control of both PF and BF is necessary to control the dimensional variations of the part.

Automotive industries, due to the highly competitive nature of international markets, are undergoing to reduce the time to market of the new products. The evaluation of durability of components at the design stage could be very effective in order to increase the reliability and to reduce the associated testing time in the experimental fields. The actual components are subjected to time variable loading so, for a correct fatigue analysis, it is necessary take into account the influences of geometrical effects, the multiaxiality of the loadings and the surface conditions. The fatigue analysis at the design stage is useful in case a FLP (Fatigue Life Prediction) tool, fully integrated to FEA (Finite Element Analysis) codes, is developed allowing design engineers to do an effective management of these techniques.

The growing use of coated sheets, aluminum alloy sheets, and coated dies has led to a veritable explosion of publications in the tribology of sheet metalworking. The present paper aims to assess the state of knowledge and provide a starting point for researchers and practitioners alike. Results of potentially valuable work are often difficult to interpret because vital pieces of information are missing. Recommendations are now made regarding the minimum requirements for characterizing the sheet, die, lubricant, and test conditions, and for reporting the results.

Environmental concerns have led to the development of automobile engines that are lightweight yet powerful. In consequence, the industry is now demanding an engine valve spring with higher fatigue strength and higher sag resistance. To meet the demands, the authors studied the influence of surface finishing and chemical compositions in Chromium-Silicon Alloy Steel on fatigue strength of steel wire for valve springs. The authors confirmed that the addition of silicon improves softening resistance while tempering, and electropolishing which eliminates surface flaws on wire are effective.

The effects of tempering on carburized Cr-Mo gear steel were investigated through mechanical and fatigue tests. Specimens were carburized at 900°C for 180 minutes, and then oil quenched at 150°C for 10 minutes of holding time and cooled to room temperature. The subsequent tempering process was performed to 160°C for 90 minutes. Surface hardness and residual compressive stress were decreased by tempering treatment, whereas tensile strength, yield strength and impact energy were increased. Bending fatigue endurance limits for both tempered and untempered specimens were same as 779MPa. The strength of roller contact fatigue is also not greatly influenced by tempering treatment. Thermal distortion for carburized transfer driven gear before and after tempering exhibited a similar distribution. Microstructural changes during tempering were also discussed.

The analysis of the wear resistance of engine components must take into account the whole system. It is of no use to improve the properties of one of the components if it will cause higher wear on the other components of the tribological system. This paper presents a study to improve the wear resistance of piston ring coatings and liner materials at the same time that the compatibility between their wear rates is focused. The diesel engine tests were run with high sulfur fuel (about 0.9 wt%) and lubricant with low total base number (TBN) with the objective of increasing the corrosive conditions. The results show that the best compatibility between the wear rates of the top rings and liners is achieved when the rings are coated by plasma spraying with a molybdenum based material containing approximately 15% of moly carbide and when the liners are made of pearlitic gray cast iron with niobium, vanadium and titanium additions.

For the development of new components, design engineers today have access to a broad amount of fatigue data, which were obtained from unnotched and notched specimens. These data can be transformed when the conditions of material, strength, geometry, surface and surface layer and loading mode in the fatigue critical areas are taken into account for constant and variable amplitude loading. The procedure of data transferability is discussed for the example of a randomly loaded truck stub axle where the failure criterion is the first detectable crack, and the local equivalent stress/strain and the maximum stressed/strained material volume are considered. In addition, several problems associated with fatigue life assessment under variable amplitude loading are discussed.

A thermal fluid flow analysis for multiflow channel(MFC) condenser for automotive air-conditioning system using HFC-134a refrigerant has been carried out. The present study has been done as a part of the work intended to develop a design tool of HFC-134a refrigerant air conditioning system for passenger vehicle by applying a steady state simulation scheme to obtain the performance optimization. Thermodynamic and flow properties of HFC-134a refrigerant and temperature profile of the air flow over the surface of MFC condenser are predicted as a function of flow channel distance using a model of finite difference method. Variations of the heat transfer rate and pressure distribution are predicted under consideration of the actual multiflow channel constructions. The results of the predicted analysis obtained from the simulation analytical model were found to be conform with the known actual operation conditions of HFC-134a condenser in passenger vehicle air conditioning system.

The effect of local fuel concentration on cyclic variability in combustion and engine performance in a lean burn stratified charge engine has been investigated. The fuel concentration in a plane close to the spark plug was measured for a large number of cycles using laser-induced fluorescence (LIF) and simultaneous measurement of in-cylinder pressure in an one-cylinder optical research engine. It could be shown quantitatively that the fuel concentration in a small region close to the spark plug has a dominating effect on the subsequent pressure development for lean mixtures. Variations in the mixture concentration in the vicinity of the spark plug contribute significantly to cyclic variation in combustion. Measurement of the flame area in the same plane 20 °CA after ignition revealed that the direction of growth of the established flame is not significantly influenced by the stoichiometry.