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Rear seat cushion frame of passenger car using PP-LFT (Long Fiber Thermoplastic) has developed for the purpose of weight reduction as well as tooling cost saving. At the design stage, dynamic structural analysis by LS-Dyna and flow analysis using MoldFlow were performed to check both validity of the cushion frame design and optimization of the injection conditions respectively. To check the degradation propensity of the candidate material, heat cycle, heat aging and fatigue tests were performed. The warpage and shrinkage characteristics of the cushion frame were also investigated through 3D-scanner. The fabricated proto cushion frame shows ∼45% weight reduction as well as ∼10% tooling cost down than conventional steel frame, which is made by steel spot welding.

This paper represents Part I of a three part series on automotive FM diversity systems. Part I focuses on a review of multipath fading. Part II (2007-01-1732) deals with analog diversity systems which have been developed to combat the effects of this fading in an FM broadcast and Part III (2007-01-1734) discusses new digital implementations of FM diversity systems that have been implemented in DSP algorithms. This paper reviews propagation channel modeling and multipath. Three cases are studied: Additive white Gaussian noise channel, the Rician channel and the Rayleigh channel. It is further noted that the Rician and Rayleigh channels can be either flat or frequency selective based on the values of the time delays in the reflected signal paths. When the delays are relatively short the channel acts like a wide filter and the fading acts on all spectral components of the signal equally.

A redesigned 2005 Chevrolet Equinox rear cradle was optimized using metamodel techniques coupled with large scale finite element simulations. The rear cradle was redesigned to accommodate an electric drive system to convert the equinox to a hybrid as part of the General Motors sponsored student project Challenge X. The design optimization uses metamodels to represent the finite element responses of the cradle under multiple loading situations. The metamodels provide an optimization technique that reduces design time and the number of required simulations compared to the traditional, iterative type simulation based optimization. The result of the optimization was a 12% weight savings over the initial design with a higher confidence in safety. The optimization results were confirmed by an extra set of finite element simulations outside of those performed for the optimization process.

This paper describes a joint project between Ford, the American Iron & Steel Institute, the University of Louisville, and the U. S. Army to reduce the weight of a full size pick-up truck by 25%, while keeping incremental costs to a minimum. Several alternate technologies were evaluated for each system, subsystem, and component of the vehicle and based on analysis of all combinations of these technologies, the solution which yielded the best overall cost and weight balance, while meeting all of the functional requirements, was selected. The major focus of the project was to develop new steel architectures and materials, since this would assure the maintenance of the lowest possible cost, though the study was not restricted to steel alone. The project was successful in meeting all of its targets, and a vehicle was built to demonstrate the feasibility of the various concepts.

This paper presents the design and manufacture a sandwich structure bumper beam that could withstand at least the same load required to have plastic deformation in a 2002 Jeep Wrangler bumper beam at a lower weight. The dimensions from a bumper beam were scaled down in order to match the limiting length of the sandwich structure specimens. Theoretical optimization calculations were conducted in order to find the optimal dimensions and face thicknesses for the hybrid structures. Sandwich panels were based on Glass Fiber Reinforced Polypropylene (Twintex) and an Aluminum foam core (Alporas). Three point bending tests were performed on the sandwich structures. The resulting failure modes were revealed and found to be in agreement with those offered by the analytical predictions.

Impact strength of pickup box floor panels is determined using a test called “The Drum Drop Test”. This drum drop test is one of the key verification requirements in the design of the pickup box floor panels. Non-linear CAE analysis is done in order to assess the performance of the pickup box design for this requirement. In this paper, a sensitivity study of various parameters that affect the performance of the pickup box floor panels is presented. Critical parameters are identified which would drive the design of the floor panels. This paper also highlights the weight reduction opportunity by using high strength steels for the design of floor panels.

This paper is concerned with modeling computer experiments with multiple responses. It has been common that one may collect multiple responses from a physical or computer experiment. However, to our best knowledge, there is little work to model computer experiment with multiple responses. In this paper, we propose a modeling procedure for such computer experiment by using a multivarate kriging model, a natural extension of the ordinary kriging model. We further extend functional ANOVA of single response to multiple response and apply it for analyzing the effect of each design variable. The proposed methodology is demonstrated by an analysis of data collected from a case study concerned with the design of the engine structure to minimize the radiated noise.

A methodology is proposed to reduce the effects of uncertainty in fatigue crack growth investigations, especially for very high cycle fatigue. The approach integrates experimental data with modeling in order to manage the uncertainty with minimal amounts of data. An extensive set of very high cycle fatigue data collected on SUJ2 bearing strength steel will be used to demonstrate the procedure. The fatigue cracks nucleate from internal particles as well as surface damage, both of which can have fatigue lives in excess of 108 cycles. Consequently, it would be advantageous to have a methodology that would predict long term fatigue life with multiple modes of damage growth by infusing limited data with fatigue modeling.

To describe fatigue crack growth, Paris law or other equivalent but more complicated laws or models are frequently used. The parametric values of a model are, in general, obtained from fitting the experimental data and presented in an average sense. Sometimes, they may not be sufficient to depict the real fatigue crack growth trend, especially when scattering of the crack growth curves are apparent. To remedy this shortcoming and to study the fatigue reliability in phases of crack growth, a computer simulation algorithm is proposed in the present paper. The algorithm takes not only the average values of model parameters but also their statistical variability into consideration. The validity of the model is studied in detail and examined through comparison made between simulation and experimental results. Both constant-amplitude and random loading conditions are considered.

This short note presents some initial results on the study of one-factor-at-a-time (OFAT) screening designs for computer experiments. Both main effects and two-factor interactions are under our consideration. After the development of swapping and union techniques in general, we study the standard OFAT plan by Daniel (1973) and Qu and Wu (2005). A fast OFAT plan is proposed with a stopping rule via capping technique, which is similar to the variable search procedure by Shainin (1988) under sign restriction.

This paper presents a robust design process for the idle vibration in a passenger vehicle. Except global modifications of a body structure, chassis system or engine mounting system, it is difficult to find the local countermeasures that can work for the idle vibration. It is a major goal of this paper to develop the local countermeasures for the idle vibration. A process for robust design is proposed, which consists of 4 steps, that is, a) problem definition, b) cause analysis, c) countermeasure development, and d) validation. In order to simplify complexities of a robust design, it is more efficient to divide the step for countermeasure development into two small phases. In the first phase for movement to the target, a deterministic design is carried out to shift the resonance frequency of exhaust far from the critical frequency range of idle.

Fatigue durability of structural components depends on geometrical features, material fatigue properties, and service loading. The scatter of the three basic factors affects also the scatter of the fatigue durability of those objects. In order to estimate the scatter of predicted fatigue durability it is necessary to describe in a consistent way the variability of the input data, i.e. the scatter of the geometrical parameters and resulting stress concentration factors and the stress magnitude and distribution in critical regions, the scatter of the material properties, and the scatter of the applied load. The statistical data, mathematical tools and their practical use leading to the evaluation of fatigue reliability and durability of welded structures in earth moving machinery is the subject of the discussion presented below.

The following document discusses the benefits achieved from implementing a digital dash-panel within an automobile. It details the synthesis of the digital display system using the appropriate hardware components and software strategies. The justifications behind the selection of the Blackfin processor for controlling the system are outlined. In addition, a brief discussion of the safety aspects obtained from the digital dash-display is discussed.

Current trends in the automotive, aerospace and other industries are resulting in the development of exceptionally large system-level models of control law or physical system behaviors. This is especially true in the propulsion systems algorithm and software development areas. The MathWorks has been actively engaged with a number of engineering groups faced with industry demands of increased software feature content with higher complexity and a shorter turn-around time. This paper discusses a roadblock encountered on a typical propulsion system software simulation due to its sheer size. It also discusses challenges, results, and lessons learned in solving the above problem from both a tool technology and engineering perspective.

Cam phasing, or Variable Valve Timing (VVT), is an electro hydraulic and mechanical camshaft control concept managed by the vehicle's microcontroller engine management system. Development and implementation of cam phasing mechanisms is pursued by the automotive industry today because it gives measurable increase in performance, and reduction in undesired engine emissions. This paper illustrates the usage of virtual prototyping techniques to efficiently investigate cam phasing architecture control algorithm implementation to permit more robust cam phasing design. The control algorithm implementation resides in Simulink, and the virtual prototype of a complete hydraulic vane cam phaser system resides in a selected analog mixed technology simulator. Co-simulation enables the two different simulation engines to communicate, hence dynamic controller development can commence against virtual hardware. Cam phaser response is heavily dependent on engine oil temperature and pressure.

The report provides an explanation of structure, functions and main components of optimum automatic DC micro engines system projection with excitation by constant magnets, used for a drive of antenna and glass hoist in modern cars. The construction optimization is made by several criteria. The length of the armature, number of slots, cross section area of slots, height of the magnet frame, diameter and number of armature winding turns, which are factored into the optimization process and provide the required mechanical characteristic of the motor. The presented CAD is realized in connection with visual object-guided programming of Borland Delphi.

Fatigue life prediction has reached a high level in respect to practical handling and accuracy in the last decades. As a result of insecure or lacking input data unacceptable deviations between numerical results and test results in terms of cycles till crack initiation are possible. On the one hand, the accuracy of Finite Element results gets better and better because of greatly increasing computer power and mesh density. Whereas on the other hand, the situation is much more critical regarding load data and especially regarding local material properties of the components (compared to specimen data). But in the last few years also the possibilities of process simulation have improved in such, that at least a few local material properties or quality indicators can be predicted with sufficient reliability.

A CAE approach for suspension system and full vehicle under durability road load conditions was conducted based on experiments and simulations. Rig and proving ground tests were used to collect road load profile, and then served as loading conditions for CAE analyses. For suspension analyses, multi-axial road load conditions obtained from rig tests were used to further study the stress distribution of suspension under road load conditions. Based on the results of stress analyses, a fatigue analysis was also conducted to predict the fatigue life of the suspension system. The approach combining proving ground tests, rig tests and CAE analyses can deliver a timely solution for durability analysis in early vehicle design stage with reasonable accuracy. Similar approach was also used to investigate the fatigue performance of full vehicle. At first, a road load condition was collected. Then a full vehicle CAE model was established and correlated with stiffness and modal experiments.

Laminated steel has been increasingly applied in automotive products for vibration and noise reduction. One of the major challenges the laminated steel poses is how to simulate forming processes and predict formability severity with acceptable correlation in production environment, which is caused by the fact that a thin polymer core possesses mechanical properties with significant difference in comparison with that of steel skins. In this study a cantilever beam test is conducted for investigating flexural behavior of the laminated steel and a finite element modeling technique is proposed for forming simulation of the laminated steel. Two production panels are analyzed for formability prediction and the results are compared with those from the try-out for validation. This procedure demonstrates that the prediction and try-out are in good agreement for both panels.

Braking has a strong effect on a vehicle's front suspension loads when the vehicle is driven over a pothole. The suspension loads of a vehicle braking while going over a pothole are also affected by vehicle design, vehicle weight and speed. In this study a simplified suspension model is presented, which is then validated by the simulation of a vehicle model. The simplified suspension model provides an efficient approach to evaluate effects of braking on wheel rebound into potholes, which determines the magnitude of impact loads when the tires hit the pothole edge. The vehicle model is used not only to validate the simplified suspension model, but also to provide the information of wheel center loads in addition to the wheel position and velocity. The analysis using the vehicle model agrees with pothole test results. The study reveals how vehicle braking affects the wheel center longitudinal forces during the pothole impact.