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A ductile failure criterion (DFC), which defines the stretching failure at localized necking (LN) and treats the critical damage as a function of strain path and initial sheet thickness, was proposed in a previous study. In this study, the DFC is revisited to extend the model to the low stress triaxiality domain and demonstrates on modeling forming limit curve (FLC) of TRIP 690. Then, the model is used to predict stretching failure in a finite element method (FEM) simulation on a TRIP 690 steel rectangular cup draw process at room temperature. Comparison shows that the results from this criterion match quite well with experimental observations.

Current die design recommendations attempt to limit the production of burrs through accurate alignment of the upper and lower edges. For common automotive exterior sheet, this translates to a gap less than 0.06mm. Unfortunately, the tolerances required by such standards often exceed the capabilities of many trim dies. The objective of the research described in this paper is to study the mechanisms of burrs generation and their impact on AHSS formability in stretch flanging. Experimental results on influence of trimming conditions on the shape of the sheared surface will be combined with the results of stretching strips after trimming.

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.

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).

Strains in most stamped parts are produced under non-proportional loading. Limit strains induced during forming are, therefore, path dependent. Experimental Forming Limit Diagrams (FLDs) are usually determined under proportional loading and are not applicable to most forming operations. Experimental results have shown that path dependent FLDs are different from those determined under proportional loading. A number of analytical methods have been used to predict FLDs under proportional loading. The authors have recently introduced a new method for predicting FLDs based on the theory of damage mechanics. The damage model was used successfully to predict proportional FLDs for VDIF steel and Al6111-T4. In this paper, the anisotropic damage model was used to predict non-proportional FLDs for VDIF steel. Experiments were conducted to validate model predictions by applying pre-stretch in plane strain followed by uniaxial and balanced biaxial tension.

The component being formed experiences some type of prestrain that may have an effect on its fatigue strength. This study investigated the forming effects on material fatigue strength of dual phase sheet steel (DP600) subjected to various uniaxial prestrains. In the as-received condition, DP600 specimens were tested for tensile properties to determine the prestraining level based on the uniform elongation corresponding to the maximum strength of DP600 on the stress-strain curve. Three different levels of prestrain at 90%, 70% and 50% of the uniform elongation were applied to uniaxial prestrain specimens for tensile tests and fatigue tests. Fatigue tests were conducted with strain controlled to obtain fatigue properties and compare them with the as-received DP600. The fatigue test results were presented with strain amplitude and Neuber's factor.

This paper describes the design and application of a business simulation to help train employees about the new business model and culture that for an automotive supplier company that designs connected vehicle and other advanced electronic products for the automotive industry. The simulation, called SIM-i-TRI, is a three to four day collaborative learning activity that simulates the executive, administrative, engineering, manufacturing, and marketing functions in three divisions of a manufacturer that supplies parts and systems to customers in industries similar to the automotive industry. It was originally designed to support the new employee orientation at the Tier 1 supplier and to provide the participants a safe environment to practice the lessons from the orientation. The simulation has been used several times a month in the US, England, and Germany for over four years.

Although computer models for vehicle and sub-system performance simulations have been developed and used extensively in the past several decades, there is currently a need to enhance the overall availability of these types of tools. Increasing demands on vehicle performance targets have intensified the need to obtain rapid feedback on the effects of vehicle modifications throughout the entire development cycle. At the same time, evolution of the PC and development of Web-based applications have contributed to the availability, accessibility, and user-friendliness of sophisticated computer analysis. Web engineering is an ideal approach in supporting globalization and is a cost-effective design-analysis integration business strategy. There is little doubt that this new approach will have positive impacts on product cost, quality, and development cycle time. This paper will show how Microsoft Excel and the Web can be powerful and effective tools in the development process.

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 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.

Always for means of a measurement of the torque of car units are made great requirements. In the paper presented the opportunities of more exact measurement of the torque using the microprocessor meter and the dynamics of an offered meter are analyzed. The use of the given torque meter will allow improving technical, economic, operational and other properties of car stands.

In the North American automotive industry, various advanced high strength steels (AHSS) are used to lighten vehicle structures, improve safety performance and fuel economy, and reduce harmful emissions. Relatively thick gages of AHSS are commonly joined to conventional high strength steels and/or mild steels using Gas Metal Arc Welding (GMAW) in the current generation body-in-white structures. Additionally, fatigue failures are most likely to occur at joints subjected to a variety of different loadings. It is therefore critical that automotive engineers need to understand the fatigue characteristics of welded joints. The Sheet Steel Fatigue Committee of the Auto/Steel Partnership (A/S-P) completed a comprehensive fatigue study on GMAW joints of both AHSS and conventional sheet steels including: DP590 GA, SAE 1008, HSLA HR 420, DP 600 HR, Boron, DQSK, TRIP 780 GI, and DP780 GI steels.

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.

This paper begins with a baseline multi-objective optimization problem for the lithium-ion battery cell. Maximizing the energy per unit separator area and minimizing the mass per unit separator area are considered as the objectives when the thickness and the porosity of the positive electrode are chosen as design variables in the baseline problem. By employing a reaction zone model of a Graphite/Iron Phosphate Lithium-ion Cell and the Genetic Algorithm, it is shown the shape of the Pareto optimal front for the formulated optimization takes a convex form. The identified shape of the Pareto optimal front is expected to guide Design of Experiments (DOE) and product design. Compared with the conventional studies whose optimizations are based on a single objective of maximizing the specific energy, the proposed multi-objective optimization approach offers more flexibility to the product designers when trade-off between conflicting objectives is required.

Most of the present electric vehicle (EV) on-board chargers utilize a conventional design, i.e., a boost-type Power Factor Correction (PFC) controller followed by an isolated DC/DC converter. Such design usually yields a ~94% wall-to-battery efficiency and 2~3kW/L power density at most, which makes a high-power charger, e.g., 20kW module difficult to fit in the vehicle. As described in this paper, first, an E-mode GaN HEMT based 7.2kW single-phase charger was built. Connecting three such modules to the three-phase grid allows a three-phase >20kW charger to be built, which compared to the conventional three-phase charger, saves the bulky DC-bus capacitor by using the indirect matrix converter topology. To push the efficiency and power density to the limit, comprehensive optimization is processed to optimize the single-phase module through incorporating the GaN HEMT switching performance and securing its zero-voltage switching.

Brake squeal is an instability issue with many parameters. This study attempts to assess the effect of thermal load on brake squeal behavior through finite element computation. The research can be divided into two parts. The first step is to analyze the thermal conditions of a brake assembly based on ANSYS Fluent. Modeling of transient temperature and thermal-structural analysis are then used in coupled thermal-mechanical analysis using complex eigenvalue methods in ANSYS Mechanical to determine the deformation and the stress established in both the disk and the pad. Thus, the influence of thermal load may be observed when using finite element methods for prediction of brake squeal propensity. A detailed finite element model of a commercial brake disc was developed and verified by experimental modal analysis and structure free-free modal analysis.

In this paper, we consider a new design of synchronous motor with salient poles rotor and all coils placed on the stator. This design, uses a laminated silicon steel rotor, which is not so expensive as a rotor with super strong permanent magnets. This design of machine eliminates copper rings on the rotor and brushes which is used in regular synchronous motors, and eliminates disadvantages involved with these arrangements. In an earlier publication, authors considered the opportunity realization of synchronous mode operation in the machine with salient pole rotor and DC stator excitation. Now, we consider the new synchronous mode operation with individual DC excitation of each the alternative current (AC) windings for realization the first, second and third phase synchronous machines. In theoretical basics of analyses and design of synchronous motors we pay more attention to the single-phase motor because it is the basis for design polyphase synchronous machines.

Warpage is the distortion induced by inhomogeneous shrinkage during injection molding of plastic parts. Uncontrolled warpage will result in dimensional instability and bring a lot of challenges to the mold design and part assembly. Current commercial simulation software for injection molding cannot provide consistently accurate warpage prediction, especially for semi-crystalline thermoplastics. In this study, the root cause of inconsistency in warpage prediction has been investigated by using injection molded polypropylene plaques with a wide range of process conditions. The warpage of injection molded plaques are measured and compared to the numerical predictions from Moldex3D. The study shows that with considering cooling rate effect on crystallization kinetics and using of the improved material model for residual stress calculations, good agreements are obtained between experiment and simulation results.

The problem of increasing the accuracy of determining the torque and the load angle of the permanent magnet synchronous motor of an electric traction drive to the predicted level (2.5...3)% of the full-scale error is solved by an indirect method. We considered the algorithms for calculating the generalized current and voltage of the electric motor, the total power, the instantaneous values of the power factor, and the sine of the phase angle between the first harmonics of voltages and currents. We determined the requirements for the accuracy of determining these values at the level of 1% of the full-scale error. We considered the algorithms for determining the total instantaneous power losses by the indirect method at the predicted level (15...20)% of the full-scale error with the efficiency of the motor (90...95)%.

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.