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In this paper, a new algorithm, named Nonlinear Optimization Method (NOM) has been mathematically and computationally developed for several geometric elements. The initial condition of the NOM is obtained by LSM, then the minimum zone is optimized in accordance with tolerancing principles in ANSI Y14.5.1M. The results are verified to be the Minimum Zone Evaluation (MZE) for the inspected geometric features. The algorithm, together with its computational realization programs, are proved to be considerably reliable and robust for practical applications.

This paper presents a real-time computer system for the control of refrigerant flow in an automotive air conditioning system. This is an experimental system used to investigate the potential advantages of electronic flow control over conventional flow control (using an orifice tube or thermal expansion valve). Two features of this system are presented. First, the system organization is described. Second, the control and interface software are presented. The emphasis is on the software. The system is organized as a closed loop control system. The inputs to the controller are measurements of the refrigerant system. In particular, thermocouples are used to measure the refrigerant temperature before and after the evaporator. The analog thermocouple signals are converted to digital form by an off-the-shelf, portable, data acquisition system (DAQ). Via a parallel port link, these digital measurements are transfered to a laptop computer.

Over the decades, several attempts have been made to develop new fatigue analysis methods for welded joints since most of the incidents in automotive structures are joints related. Therefore, a reliable and effective fatigue damage parameter is needed to properly predict the failure location and fatigue life of these welded structures to reduce the hardware testing, time, and the associated cost. The nodal force-based structural stress approach is becoming widely used in fatigue life assessment of welded structures. In this paper, a new nodal force-based structural stress recovery procedure is proposed that uses the least squares method to linearly smooth the stresses in elements along the weld line. Weight function is introduced to give flexibility in choosing different weighting schemes between elements. Two typical weighting schemes are discussed and compared.

This paper presents a comparison of aqueous corrosion rates in 5% NaCl solution for eight experimental creep-resistant magnesium alloys considered for automotive powertrain applications, as well as three reference alloys (pure magnesium, AM50B and AZ91D). The corrosion rates were measured using the techniques of titration, weight loss, hydrogen evolution, and DC polarization. The corrosion rates measured by these techniques are compared with each other as well as with those obtained with salt-spray testing using ASTM B117. The advantages and disadvantages of the various corrosion measurement techniques are discussed.

This paper presents cost-benefit analysis of glass and carbon fiber reinforced thermoplastic matrix composites for structural automotive applications based on press forming operation. Press forming is very similar to stamping operation for steel. The structural automotive applications involve beam type components. The part selected for a case study analysis is a crossbeam support for instrument panels.

The effects of engine noise in plastic manifolds has been a subject of study in the automotive Industry. Several SAE papers have been published on the subject. Most testing described requires access to engine dynamometers and other elaborate equipment. As part of a general study of plastic intake manifold noise characteristics, this study was undertaken to develop a synthesis bench for enabling low cost noise testing of plastic induction systems including plastic manifolds. Computer simulation of engine intake noise was used as part of a correlation between the plastic manifold synthesis bench and actual engine measurements. The Fast Fourier Transform (FFT) analysis provided analogous results between the predicted theoretical and two measured signals with a fundamental frequency at approximately 80 Hz. Qualitative and statistical comparisons of the time domain signals also proved equally favourable. Recommendations are included for further development of this approach.

Since the large scale production of plastic throttle bodies in 1994 there have been a number of further introducions. However the universal adaptation of plastic for the throttle body has not yet occurred. This paper will describe design approaches and processing solutions to facilitate low cost precision manufacturing with test results of actual parts made by these approaches. Introductions: 1994 U.K. 4 cylinder engine, cable operation 1998 Germany 4 cylinder engine, cable operation 1999 U.S. 4 cylinder engine cable operation

With increasing use of biofuels in the automotive industry, it has become necessary to evaluate their effects on the properties of polymers used in the fuel delivery systems. In this study, we have considered the effect of biodiesel on the tensile properties of nylon-6, 30% E-glass fiber reinforced nylon-6 and impact-modified nylon-6. The tensile specimens were immersed in 100% biodiesel for up to 7 days before determining their tensile properties. Another set of specimens were immersed in 100% biodiesel under stressed condition and then their tensile properties were determined. The absorption of biodiesel and their effects on tensile modulus, tensile strength and failure strain are reported in this paper.

This study reports the performance of three different automotive magnesium substrate materials (AM60B diecastings, AZ31-H24 sheet, and AM30 extrusions), each bonded to a common aluminum reference material with two different toughened adhesives. The magnesium substrates were pretreated with six different commercial pretreatments both with and without a final fused-powder polymeric topcoat. These samples were then evaluated by comparing initial lap-shear strength to the lap-shear strength after cyclic-corrosion testing. Additionally, use of a scribe through the polymer primer permitted assessment of: 1) distance of corrosion undercutting from the scribe (filiform), and 2) percent corrosion over the area of the coupon. The results showed that the performance of each magnesium pretreatment varied on cast AM60B, sheet AZ31-H24, and extruded AM30 substrates.

This study considers the thermal stresses in single lap adhesive joints between magnesium and steel. The source of thermal stresses is the large difference in the coefficients of thermal expansion of magnesium and steel. Two different temperature differentials from the ambient conditions (23°C) were considered, namely -30°C and +50°C. Thermal stresses were determined using finite element analysis. In addition to Mg-steel substrate combination, Mg-Mg and steel-steel combinations were also studied. Combined effect of temperature variation and applied load was also explored. It was observed that temperature increase or decrease can cause significant thermal stresses in the adhesive layer and thermal stress distribution in the adhesive layer depends on the substrate combination and the applied load.

Intake systems for automotive use have been progressively converted to lighter weight materials over the past decade or so. Meeting all of the operational requirements for an intake system is a “given”, as well as meeting those additional requirements associated with conditions which are considered to be abnormal or undesired. As is frequently the case, the very abnormality of the undesired conditions (“e.g. backfires”) is accompanied by a lack of published data. In attempting to collect data for “intake backfires” one encounters the test complications associated with running pyrotechnic events in an industrial environment. This paper discusses an approach by Rose Hulman Institute of Technology, supported by Siemens automotive,to develop a non pyrotechnic test that could be used to authenticate simulations and steady state tests.

Charge boosting strategy plays an essential role in improving the power density of diesel engines while meeting stringent emissions regulations. In downsized two-stage turbocharged engines, turbocharger matching is critical to achieve desired boost pressure while maintaining sufficiently fast transient response. A numerical simulation model is developed to evaluate the effect of two-stage turbocharger configurations on the perceived vehicle acceleration. The simulation model developed in GT-SUITE consists of engine, drivetrain, and vehicle dynamics sub-models. A model-based turbocharger control logic is developed in MATLAB using an analytical compressor model and a mean-value engine model. The components of the two-stage turbocharging system evaluated in this study include a variable geometry turbine in the high-pressure stage, a compressor bypass valve in the low-pressure stage and an electrically assisted turbocharger in the low-pressure stage.

Owing to their weight saving potential and improved flexural stiffness, metal-polymer-metal sandwich laminates are finding increasing applications in recent years. Increased use of such laminates for automotive body panels and structures requires not only a better understanding of their mechanical behavior, but also their formability characteristics. This study focuses on the formability of a metal–polymer-metal sandwich laminate that consists of AA5182 aluminum alloy as the outer skin layers and polypropylene (PP) as the inner core. The forming limit curves of Al/PP/Al sandwich laminates are determined using finite element simulations of Nakazima test specimens. The numerical model is validated by comparing the simulated results with published experimental results. Strain paths for different specimen widths are recorded.

This study investigates numerically and experimentally the formability of two Fiber-Metal Laminate systems based on a thermoplastic self-reinforced polypropylene and a glass fiber polypropylene composite materials. These hybrid systems consist of layered arrangements of aluminum 2024-T3 sheets and thermoplastic-based composite materials. Flat panels were manufactured using a fast one step cold press manufacturing procedure. Punch-stretch forming tests and numerical simulations were performed in order to evaluate the formability of the hybrid systems. Experimental and simulation results revealed that the self reinforced thermoplastic composite-based Fiber-Metal Laminate exhibit excellent forming properties similar to that of the monolithic aluminum alloy of comparable thickness.

Computational analysis of flow field inside a high pressure swirl injector is carried out. The effects of injection pressure and internal geometry on velocity field inside the nozzle and especially at the injector exit are studied in detail. From the velocity distribution at the exit plane, methods to determine the discharge coefficient and liquid sheet cone angle are given. To validate the computational model, the spray cone angles in the immediate vicinity of the nozzle exit were measured from photographs over the injection pressure differential range of 3.5 to 10.3 MPa. Static flow rates were measured using a flow meter over the same pressure range. The calculated results are found to be consistent with the experimental measurements. Extensive calculations were then conducted to examine the influence of swirl inlet port area and orifice diameter on discharge coefficient and spray cone angle.

This paper investigates the interfacial fracture properties of composite-metal laminates by using the single-cantilever beam testing technique. The hybrid systems consisted of a layer of aluminum alloy (6061 or 2024-T3) bonded to polypropylene based composites. In this study, two non-chromate surface treatments were applied to the aluminum substrates: SafeGard CC-300 Chrome free seal (from Sanchem Inc.) and TCP-HF (from Metalast International Inc.). These are environmentally friendly surface treatments that enhance the adhesion and corrosion resistance of aluminum alloys. Flat hybrid panels were manufactured using a one step cold press manufacturing procedure. Single cantilever bend specimens were cut from the panels and tested at 1mm/min. Results have shown that the CC-300 treated Al 2024-T3 alloy and Twintex exhibited higher interfacial fracture energy values.

Current plastic intake manifolds are manufactured using the injection molding process. In this paper, thermoforming is explored as an alternative to injection molding for making intake manifold shells, which can then be joined by one of the welding techniques used for thermoplastic materials. The investigation reported here includes press-forming experiments of a simple bowl shaped shell and subsequent welding experiments to join these shells.

LS-DYNA3D has been widely used to perform computer simulation of sheet metal forming. In the material library of LS-DYNA3D there are a number of user defined material models. In order to take full advantage of the material subroutines, it is important for the users to be able to display user defined history variables in the post processing and to establish user-defined failure criterion. In this report, the development of a damage coupled plastic model is firstly described. The damage model is then programmed in a user defined material subroutine. This is followed by performing finite element simulation of sheet metal forming with the LS-DYNA3D that has incorporated the damage coupled plastic model. The way to display the user defined history variables and how to deal with the failure criterion during the postprocessing of ETA/DYNAFORM are described. History variable distributions at several time steps are displayed and discussed in this paper.

This paper describes the development of a dedicated multi-physics solver, developed using a Fortran compiler. It simulates the behavior of a Balanced Canister Purge Solenoid valve. Although FEA can contribute to the development of a product it is not always possible to rely solely on this type of tool for help since it may not deliver all that is required, depending on the product and the environment. A more innovative approach has found some success in addressing the math-modeling needs of an advanced design group at this manufacturing facility. It involves the use of a more versatile tool, which places the emphasis on real time monitoring of combined physical phenomenon as opposed to steady-state or transient analysis of a single phenomenon. This type of tool has been called multi-physics (MP) or multi-technology1 modeling and can be implemented several ways. One way includes the use of structured codes such as Fortran or C++ to produce a dedicated solver.

This study was conducted to develop and validate a multidimensional measure of shift quality as perceived by drivers during kick-down shift events for automatic transmission vehicles. As part of the first study, a survey was conducted among common drivers to identify primary factors used to describe subjective gear-shifting qualities. A factor analysis on the survey data revealed four semantic subdimensions. These subdimensions include responsiveness, smoothness, unperceivable, and strength. Based on the four descriptive terms, a measure with semantic scales on each subdimension was developed and used in an experiment as the second study. Twelve participants drove and evaluated five vehicles with different gear shifting patterns. Participants were asked to make kick-down events with two different driving intentions (mild vs. sporty) across three different speeds on actual roadway (local streets and highway).