Browse Topic: Vehicle body pillars

Items (66)

Vehicle Door Cutline Determination with Mathematical Modelling on CATIA V5

2019-28-010710/11/2019

Door shut-line definition is the first vital step in car body door engineering and depends on the hinge position, hinge shape, manufacturing capabilities and other parameters. In the design process, once the hinge axis definition is finalized door shut-line is defined which should satisfy two major requirements. The requirements are clearance between the door outer surface with its surrounding components (like hinges, fender, other door etc.) and assembly feasibility. Another one is the manufacturability of the proposed design. The above conditions must be checked on different locations of the door as well as w.r.t different openings of the door. The paper presents a mathematical model to determine the door shut-line position with great computational efficiency. This method propounds closure engineer with parameters to define the shut line rather than going for cumbersome manual iterative process. Instead of following an iterative approach to determine a limit for the shut-line, paper presents a mathematical formulation with an implicit equation. An innovative approach to solve implicit equation on CATIA is also discussed which significantly reduces the processing time. This paper inherently discusses a series of challenges which a user faces while determining the door shut-line and provides feasible solutions for those problems.

Askari, Hasan, Pandey, Pawan, Raadhaasaminathan, Sreebalajinarayanan

Numerical Investigation of Wiper Drawback

2019-01-06404/2/2019

Windscreen wipers are an integral component of the windscreen cleaning systems of most vehicles, trains, cars, trucks, boats and some planes. Wipers are used to clear rain, snow, and dirt from the windscreen pushing the water from the wiped surface. Under certain conditions however, water which has been driven to the edge of the windscreen by the wiper can be drawn back into the driver’s field of view by aerodynamic forces introduced by the wiper motion. This is wiper drawback, an undesirable phenomenon as the water which is drawn back on to the windscreen can reduce driver’s vision and makes the wiper less effective. The phenomena of wiper drawback can be tested for in climatic tunnels using sprayer systems to wet the windscreen. However, these tests require a bespoke test property or prototype vehicle, which means that the tests are done fairly late in the development of the vehicle. Furthermore, these results do not provide significant insight into the mechanisms driving the wiper drawback. In order to better understand wiper drawback a numerical simulation is presented of a configuration known to exhibit this phenomenon. This requires the inclusion into an aerodynamics solver of: moving wipers, a surface film model, and a representation of airborne spray. Using the results of this simulation, the forces causing the drawback of the water film, along with the mechanism for introducing these forces are studied. Through understanding the driving factors in wiper drawback, it can be avoided earlier in the development cycle.

Jilesen, Jonathan, Gaylard, Adrian, Linden, Tom

Effects of Rear Slant Angles on the Flow Characteristics of the Ahmed Body by IDDES Simulations

2018-01-07204/3/2018

The present study aims to investigate the effects of the several rear slant angles, φ = 25°, 30°, 32°, 33° and 35°, on the wake characteristics downstream of the Ahmed body because the angle of the rear window plays an important role in the flow characteristics. This work presents numerical simulations using ISIS-CFD flow solver which is developed by Centrale Nantes and CNRS. The turbulence model used is an hybrid RANS-LES model: the Improved Delayed Detached Eddy Simulation (IDDES). Detailed discussions of the flow features are provided using time-averaged streamlines, vorticity contours, turbulent kinetic energy contours and an iso-surface of l2. Drag and lift coefficients are also presented. In the symmetry plane, three critical flow points, which correspond to foci of separation and saddle point in the wake of the Ahmed body, and the focus of separation over the slanted surface are presented. When the slant angle increases, these critical points move near the Ahmed body before moving away the model when the slant angle is higher than 33°. For the slant angle φ = 35°, a low drag configuration is predicted while for the other slant angles, a high drag flow configuration is predicted where two C-pillars vortex are present. These vortices move away the model when the slant angle increases.

Guilmineau, Emmanuel

2019 XC40 showcases Volvo's new CMA platform

18AUTP02_142/1/2018

While some larger OEMs have lagged behind the bulging crossover curve, Volvo is launching its third in two years. The 2019 XC40, Volvo's first premium compact CUV and its first global 40-series vehicle, is easily identified as a family member. Volvo calls it a design “cousin” (not a sibling) to its larger XC60 and XC90 stablemates, with its own character. It is also the Swedish maker's first vehicle on the new Compact Modular Architecture (CMA) platform shared with Chinese parent Geely Automobile and the first available through an all-inclusive “Care by Volvo” subscription as an alternative to a traditional sale or lease.

Witzenburg, Gary

Surface Flow Visualization on a Full-Scale Passenger Car with Quantitative Tuft Image Processing

2016-01-15824/5/2016

Flow visualization techniques are widely used in aerodynamics to investigate the surface trace pattern. In this experimental investigation, the surface flow pattern over the rear end of a full-scale passenger car is studied using tufts. The movement of the tufts is recorded with a DSLR still camera, which continuously takes pictures. A novel and efficient tuft image processing algorithm has been developed to extract the tuft orientations in each image. This allows the extraction of the mean tuft angle and other such statistics. From the extracted tuft angles, streamline plots are created to identify points of interest, such as saddle points as well as separation and reattachment lines. Furthermore, the information about the tuft orientation in each time step allows studying steady and unsteady flow phenomena. Hence, the tuft image processing algorithm provides more detailed information about the surface flow than the traditional tuft method. The main advantages over other flow visualization methods, such as oil paint, is that experimental facilities are not contaminated and statistical data can be extracted. The investigated surface pattern shows a symmetric flow on the entire rear end section of the passenger car. The flow field on the roof, backlight, and upper trunk deck is attached almost everywhere. However, two small regions indicate the presence of two counter-rotating vortices at the lower edge of the backlight (rear window). Those vortices are also detectable in the distribution of the tuft angle standard deviation. A bifurcation line is present at each side of the trunk due to the streamwise vortices originating at the C-pillars. The tuft streamlines created with this novel tuft method are compared to a standard oil paint flow visualization to validate the calculated tuft flow pattern. A critical comparison between the methods confirms that the flow tuft analysis algorithm functions flawlessly as a highly detailed flow analysis tool without the mess of oil paint.

Wieser, Dirk, Bonitz, Sabine, Lofdahl, Lennart, Broniewicz, Alexander, Nayeri, Christian, Paschereit, Christian, Larsson, Lars

Numerical Simulation of Noise Transmission from A-pillar Induced Turbulence into a Simplified Car Cabin

2015-01-23226/15/2015

At high cruising speed, the car A-pillars generate turbulent air flow around the vehicle. The resulting aerodynamic pressure applied on the windows significantly contributes to the total cabin noise. In order to predict this particular noise contribution, the physic of both the flow and the cabin needs to be accurately modeled. This paper presents an efficient methodology to predict the turbulent noise transmission through the car windows. The method relies on a two-step approach: the first step is the computation of the exterior aero-dynamic field using an unsteady CFD solver (PowerFLOW); the second step consists in the computation of the acoustic propagation inside the cabin using a finite element vibro-acoustic solver (ACTRAN). The simplified car cabin of Hyundai Motor Company, studied in this paper, involves aluminum skin, windows, sealant, inner air cavity and acoustic treatment inside the passenger compartment (porous material, damping layer). A pure vibro-acoustic model with hammer shock excitation on a window is first built. Acoustic results inside the cabin are then correlated with measurements in order to validate the vibro-acoustic modeling of the cabin, which is deemed as invariant regarding the imposed excitation types. Finally, aerodynamic pressure results from CFD are mapped on the structure mesh of the two lateral windows and the front windshield, causing structure vibration and consequently acoustic response in the cabin. Four flow conditions are studied, involving two cruising speeds (110km/h and 130km/h) and two yaw angles (0° and 10° orientations). The total wind noise level results and the relative contributions of the different windows/windshield are presented and compared to measurements.

Ganty, Bastien, Jacqmot, Jonathan, Zhou, Ze, Jeong, ChanHee

Advances in Modelling A-Pillar Water Overflow

2015-01-15494/14/2015

Driving when it is raining can be a stressful experience. Having a clear unobstructed view of the vehicles and road around you under these conditions is especially important. Heavy rain conditions can however overwhelm water management devices resulting in water rivulets flowing over the vehicle's side glass. These rivulets can significantly impair the driver's ability to see the door mirror, and laterally onto junctions. Designing water management features for vehicles is a challenging venture as testing is not normally possible until late in the design phase. Additionally traditional water management features such as grooves and channels have both undesirable design and wind noise implications. Having the ability to detect water management issues such as A-pillar overflow earlier in the design cycle is desirable to minimize the negative impact of water management features. Numerical simulation of windscreen water management is desirable for this reason. This paper focuses on recent advances towards the goal of simulating A-pillar overflow. This includes a validation study on a Jaguar saloon, including both numerical simulations using Exa PowerFLOW™, a commercially available LatticeBoltzmann (LBM) CFD solver and experimental testing in a thermal wind tunnel. The experimental procedure, which is based on the use of UV dye and a surface release point, is described. The results at two difference vehicle speeds are then compared with those of simulation. The CFD results are then used to further investigate the mechanisms determining the point at which the A-pillar is breached. This includes a detailed investigation of the flow structures around the A-pillar and their effect on water management. Overall the study explores the mechanism of A-pillar overflow onto the side glass and provides much-needed validation of the CFD technique for simulating this mechanism.

Jilesen, Jonathan, Gaylard, Adrian, Spruss, Iwo, Kuthada, Timo, Wiedemann, Jochen

Manipulation of the Aerodynamic Behavior of the DrivAer Model with Fluidic Oscillators

2015-01-15404/14/2015

The effect of an active flow control method is investigated on a 1:4 scale realistic vehicle model called “DrivAer” with notchback geometry. The wind tunnel experiments are conducted at a Reynolds number of Re=3.0·106. Fluidic oscillators are applied at the c-pillars and at the upper rear edge of the window. The actuators are installed inside the hollow designed model emitting a high frequency sweeping jet. The spacing of the actuators, the mass flow rate, and the position of actuation are varied. The effect of the active flow control on the car is investigated with force and surface pressure measurements. The surface trace pattern is visualized with tufts for the active flow control cases and the baseline case. A tuft algorithm analyzes provides statistical data of the flow angles. Moreover, particle image velocimetry measurements are performed in the plane of symmetry for β=0° to capture the flow field at the rear end and the wake. The results indicate a significant pressure increase at the backlight and the upper trunk for increasing mass flow rates of the actuators. An increased pressure level of ΔCP≈+0.35 is found compared to the non-actuated case. Furthermore, the aerodynamic forces show a decrease of the net drag of approximately ΔCD,corr≈−3.5%. The downforce varies between ΔCL,corr≈−25% and +38% depending on the actuation case. The tuft visualizations indicate a modification in the surface trace pattern at the rear end section of the notchback. The asymmetrical vortical structures at the backlight are typical on notchback rear ends and become smaller or vanish. The PIV measurements show a changed wake structure with a shifted location of the free stagnation point. Hence, the application of oscillating jets demonstrates a high potential to change the aerodynamic behavior of a realistic road vehicle design.

Wieser, Dirk, Lang, Henning, Nayeri, Christian, Paschereit, Christian

Analysis of Damage Caused to Vehicle Body Panels by Impacting Hail and Various Tools and Objects

2013-01-14384/8/2013

On the 25th December 2011 there was a hail storm in the state of Victoria, Australia, which caused approximately AU$712 million worth of damage. Some of this damage was caused to passenger vehicles. The authors conducted a number of inspections of hail-damaged vehicles as a result of insurance claims being disputed or rejected on the basis that some, or all, of the alleged hail damage was not created by hail but instead created intentionally by the vehicles' owners with the use of different tools and/or objects. As a result of the inspections and investigations of potentially fraudulent claims, the authors conducted a total of 119 tests designed to replicate damage caused to vehicle body panels by impacting hail and to recreate claimed hail damage by using tools and other objects. To do so, the authors created two sizes of hail: Ø20 mm and Ø40 mm hail. A total of 15 impact tests were conducted with Ø20 mm hail. The impact speed for the Ø20 mm hail varied between 75 km/h and 144 km/h, with the average being 113 km/h. A total of 50 impact tests were conducted with Ø40 mm hail. The impact speed for the Ø40 mm hail varied between 66 km/h and 133 km/h, with the average being 101 km/h. The testing impact speeds were generally higher than the terminal velocities of the corresponding hail, so the damage observed is expected to be an over estimation of the actual damage caused by hail. The hail was projected at the test vehicle using a purpose-built projectile launching device that used a sling-like mechanism to project hail in a horizontal direction at a test vehicle. The test vehicle was a white-colored 2001 model Holden Commodore with non-metallic paint. The body panels tested were: bonnet, roof, boot, all four doors, the vehicle pillars and cant rail. High speed cameras were used to determine the impact speed of the hail. Damage was photographed and recorded. In addition to impacting the vehicle with hail, a number of different tools and objects were used to recreate man-made damage. Tools and objects used were: claw hammer (conventional), welding hammer, ball-peen hammer, mason hammer, lead ball sink in a sock, golf ball in a sock, ratchet, breaker bar, crowbar and center punch. The conducted tests revealed the following findings: 1. hail impacting the vehicle body panels will not scratch or mark the paint but the paint may chip if hail impacts the vehicle near a fold or edge of a panel; 2. dents caused by hail will cause the light to move smoothly and continuously across the dent and the light will not "break" or crease; 3. where dents were caused by tools and objects the light will crease into multiple (two or more) distinct areas as it passes over the dent; 4. scratches and/or markings in the paint were identified on dents caused by tools and objects; 5. folds and curves on the panels did not affect the size of the dent caused to the panel; using the same tool and force to impact two different body panels (A-pillar and roof) resulted in dents that were very similar in physical appearance; 6. for the same impact speed the larger Ø40 mm hail caused more damage than the Ø20 mm hail; and 7. for the same size hail the higher impact speed hail caused more damage.

Josevski, Nikola, Sandvik, Andreas, Jones, Chris, Pok, Tandy, Orton, Tia, Richardson, Shane

Aerodynamic Pitching Stability of Sedan-Type Vehicles Influenced by Pillar-Shape Configurations

2013-01-12584/8/2013

The present study investigated the aerodynamic pitching stability of sedan-type vehicles under the influence of A- and C-pillar geometrical configurations. The numerical method used for the investigation is based on the Large Eddy Simulation (LES) method. Whilst, the Arbitrary Lagrangian-Eulerian (ALE) method was employed to realize the prescribed pitching oscillation of vehicles during dynamic pitching and fluid flow coupled simulations. The trailing vortices that shed from the A-pillar and C-pillar edges produced the opposite tendencies on how they affect the aerodynamic pitching stability of vehicles. In particular, the vortex shed from the A-pillar edge tended to enhance the pitching oscillation of vehicle, while the vortex shed from the C-pillar edge tended to suppress it. Hence, the vehicle with rounded A-pillar and angular C-pillar exhibited a higher aerodynamic damping than the vehicle with the opposite A- and C-pillars configurations. The underlying aerodynamic damping mechanism has been verified through flow visualization of phase-averaged results.

Cheng, See Yuan, Tsubokura, Makoto, Okada, Yoshihiro, Nakashima, Takuji, Nouzawa, Takahide

Severe Frontal Collisions with Partial Overlap - Two Decades of Car Safety Development

2013-01-07594/8/2013

Frontal Severe Partial Overlap Collisions (SPOC) also called small overlap crashes pose special challenges with respect to structural design as well as occupant protection. In the early 1990s, the SPOC test method was developed addressing 20-40% overlap against a fixed rigid barrier with initial velocities up to 65 km/h. The knowledge gained has been used in the design of Volvo vehicles since then. Important design principles include front side members orientated along the wheel envelopes together with a strong support structure utilizing a space frame principle with beams loaded mainly in tension and compression. This novel setup was first introduced in the 850-model in 1991 and has been refined and patented (2001) in later Volvo front structures. Among the design principles are multiple front side members on each side, helping energy absorption efficiency and robustness. The upper side members absorb energy and also transfer the forces via the A-pillars into the roof and the reinforced body and door structures. The lower side members are connected by a cross member with balanced design combining strength and energy absorption using truss principles. The overall design is made to address loads in multiple directions as well as mitigate front wheel intrusion into the passenger compartment. Real world data, complemented with laboratory testing, show that the improvements have substantial effect on occupant protection, reducing overall injuries over the years and reducing footwell intrusion related injuries specifically.

Jakobsson, Lotta, McInally, Graeme, Axelson, Anders, Lindman, Magdalena, Kling, Anders, Broberg, Thomas, Fermér, Mikael, Wågström, Linus

Numerical Simulations of Aeroacoustic Fields around Automobile Rear-View Mirrors

2012-01-05864/16/2012

A numerical method to simulate aeroacoustic fields around automobiles is proposed in the present paper. The proposed method can be used to compute sound emissions directly in both far fields and near fields. Sound passes through body structures near A-pillars and rear-view mirrors. The direct predictions of the sound to passengers therefore require solutions of acoustic near fields. Most aeroacoustics simulations around automobiles are based on Lighthill's analogy. Strictly speaking, Lighthill's analogy is not consistent in near fields because near fields are not governed by a simple wave equation. In the present paper, a proper approach is proposed to achieve further progress in the simulation of aeroacoustic fields around automobiles. The difficulties occur because the sound pressure is much smaller than the vortical flow pressure. The present method uses a flow/acoustics splitting technique that derives the modeled acoustic equations under the assumption that there is no acoustic feedback to the flows. The present acoustic equations are defined based on the difference between the compressible and incompressible flow equations. The acoustic equations are calculated with the fourth-order weighted essentially non-oscillatory scheme for the finite volume method, and a number of techniques are used to reduce the calculation time. These techniques use different meshes, time-step sizes, and computational regions in each flow and acoustics calculation. As a result, the present method makes it possible to simulate the acoustic near fields around the rear-view mirrors mounted on a vehicle. The acoustic fields for three different mirror shapes, namely, a baseline mirror, a mirror with a sharp edge around its stay, and a mirror with a sharp edge around its tip, are considered in the present paper. Consequently, the sound emissions from the mirrors and A-pillars are clearly visualized in the near fields as wall as the far fields, and differences in the acoustic fields among the mirror shapes are clarified.

Kato, Yoshihiro

Evaluation of Dynamic Roof Deformation in Rollover Crash Tests

2011-01-10934/12/2011

Although the measured amount of roof deformation associated with a given rollover crash test is often the residual or post test deformation, rollover crash test researchers are aware that roof deformation occurs dynamically throughout the rollover event with varying magnitude. The challenge to quantifying dynamic roof deformation has been the lack of a reliable method to measure and record the dynamic roof deformation during the rollover test. Researchers have explored various methods to measure dynamic roof deformation including the use of film analysis of external targets, accelerometers, string potentiometers, and 3D photogrammetry. This paper discusses a series of simulated curb trip rollover tests conducted to study and compare different methodologies to measure and record dynamic roof deformation. The tests involved midsize crossover utility vehicles instrumented with accelerometers on the roof rails at the A and B pillars and string potentiometer arrays at roof locations above the front driver and passenger seating locations. High speed digital motion cameras were rigidly mounted inside the vehicles to monitor the movement of the interior roof targets as the roof deformed during the rollover event. This paper discusses and compares the dynamic roof deformation data as measured by the roof string potentiometers and 3D photogrammetry as compared to post-test residual deformation measurements.

Harvin, Stuart W., O'Brien-Mitchell, Bridget M., Dwoinen, Andrew R., Nassoiy, Carol Ann, Motowski, Daniel F., Melocchi, Anthony G., Lu, Huizhen, Peace, Manuel V.

Robust Optimization of Drawbead Forces for a B-pillar Stamping

2009-01-09804/20/2009

Many uncertainties exist in the sheet metal stamping such as the variation of incoming material properties, die and press setup conditions, long-term tool wear and degradations. They are interacting in a way to make the process less robust, thus contributing to increased scrap rates and more unscheduled downtime. This paper presents a new approach for the die design optimization where these uncertainties are taken into account. A Tailor-Welded B-pillar consisting of 1.65mm DP600 and 0.9mm DDQ is selected as the focal part to demonstrate the new design process. The study is divided into two phases. The focus of the first phase is to understand the complexity of the formability window and determine effective optimization techniques under deterministic conditions. It is found that the formability window is highly nonlinear, or even discontinuous if a global objective function such as the Maximum Failure Factor is used. It is therefore more advantageous to adopt a regional approach where the split-prone zones and wrinkle-prone zones are identified. Optimization can then take place for each region with a multi-objective approach using the Non-dominated Sorting Genetic Algorithm (NSGA-II). The second phase takes into account the stamping uncertainties, and both the formability values and their deviations are optimized simultaneously for robustness. It is demonstrated that the robust optimization under uncertainties is able to reduce output variability while maintaining the same level of “optimal” performance as compared with deterministic optimization.

Li, Dayong, Chang, Tony, Wang, Yu-Wei, Xia, Z. Cedric

Hydroforming: Benefits, obstacles, experience and opportunities

2007-01-259911/28/2007

The weight reduction in vehicles is a subject of increasing importance at this moment in the automotive industry following the application of ultra high strength steels. Lightest vehicles bring material and energy economy, and also go in favor of the current environmental politics. The vehicles weight cannot be reduced without engineering changes, reason for new producing methods of lighter steel components are being developed, reducing the amount of the vehicles components. One of these techniques is the Hydroforming. Hydroforming consists in use the fluid pressure in substitution of the punch in a conventional press tooling to form the desired shape of the components. The technique is very useful to produce entire components that would be made in conventional way for multiples pressed components joined later. For example, a typical chassis set that would be normally made by up to six presses and welded components can be hydroformed as a single part. Generally the Hydroforming process is an elegant technique. It is also much more robust and practical that many industries will accept. This robustness will assure its increasing use. It is intended in this work to present benefits gotten in a development made by Benteler for a rear axle and an estimated cost comparison among conventional press process, hot stamping and Hydroforming for B and C pillars.

Gandara, Irineu, Berti, Wagner

Reduction in Vehicle Temperatures and Fuel Use from Cabin Ventilation, Solar-Reflective Paint, and a New Solar-Reflective Glazing

2007-01-11944/16/2007

A new type of solar-reflective glass that improves reflection of the near-infrared (NIR) portion of the solar spectrum has been developed. Also developed was a prototype solar-reflective paint that increases the NIR reflection of opaque vehicle surfaces while maintaining desired colors in the visible portion of the spectrum. Both of these technologies, as well as solar-powered parked car ventilation, were tested on a Cadillac STS as part of the Improved Mobile Air Conditioning Cooperative Research Program (I-MAC). Significant reductions in interior and vehicle skin temperatures were measured. The National Renewable Energy Laboratory (NREL) performed an analysis to determine the impact of reducing the thermal load on the vehicle. A simplified cabin thermal/fluid model was run to predict the potential reduction in A/C system capacity. The potential reduction in fuel use was calculated using a vehicle simulation tool developed by the U.S. Department of Energy (DOE).

Rugh, John P., Chaney, Lawrence, Lustbader, Jason, Meyer, John

Design of Dual Sliding Door for a Small-size Car and Its Validation Using CAE Tools

2007-01-08894/16/2007

Sliding doors are usually employed on the rear side of minivans and some large vehicles for easy egress and ingress. Furthermore, dual sliding doors are frequently observed in various concept models. This paper describes design of a dual sliding door for a small-size car. A new sliding mechanism with two sliding contact points is proposed with the B-pillar incorporated in the door structure made of high strength steel. Two sliding tracks are located in the door and the rocker panel. The door linkages first swivel and then slide with the help of the rollers in the tracks to open the door. The sliding mechanism and the door structure were validated using CAE tools such as HyperMesh, MSC/NASTRAN [2] and LS-DYNA[3]. This validation process was divided into three parts: (1) Dynamic Stiffness Analysis or the normal mode analysis to understand the natural frequency response of the door. (2) Static Stiffness Analysis or the Door Sag analysis was conducted to see the structural strength of the door in static loading. Finally, (3) Quasi-static side intrusion analysis was performed to see the resistance of the door structure against an intruding pole. The analysis results showed that the door structure achieved the desired structural performance requirements.

Shah, Kalpak, Kang, Hong Tae, Deshmukh, Upendra

The Measurement of Transient Aerodynamics Using an Oscillating Model Facility

2006-01-03384/3/2006

A method for the estimation of transient aerodynamic data from dynamic wind tunnel tests has been developed and employed in the study of the unsteady response of simple automotive type bodies. The paper describes the facility and analysis techniques employed and reports the results of a parametric study of model rear slant angle and of the influence of C-pillar strakes. The model is shown to exhibit damped, self-sustained and self-excited behaviour. The transient results are compared with quasi-steady predictions based on conventional tunnel balance data through the calculation of derivative magnification factors. For all slant angles tested the results show that the quasi-steady prediction is a poor estimate of the real transient behaviour. In addition the slant angle is shown to have significant effect on the level of unsteadiness. The addition of C-pillar strakes is shown to stabilise the flow with even small height strakes yielding responses well below that of steady-state.

Passmore, M. A., Mansor, S.

Framed Door x Fully Stamped Door

2003-01-365811/18/2003

When designing a new subsystem for a new vehicle platform, technical requirements, performance targets and cost implications drive the decision process towards which concept to be adopted. If this platform is planned for worldwide introduction, local requirements and capabilities have to be put into the business equation. Among the possible design options for a Side Door Subsystem, including basically Inset doors and Limo doors with their variations, the best for the market is selected on: Commonality requirements through the platform family; Technical implications of each design concept; Technical excellence to produce parts with the required quality/cost in the local market; Costs and timing associated with each design concept; Benchmarking. This composition of factors drove the decision to adopt different design options for South America and Europe on the recently launched small car platform. This paper demonstrates the rationale of this decision making process and the positive outcomes of it.

da Cunha Mello, Fernando Dupin, Campos, Frederico

New Concept Body

2003-01-282710/27/2003

As methods for achieving the utmost in usability and convenience, we have attempted to eliminate the center pillar (left side B-pillar), which is the main column of the body frame, and have also developed the world's lightest passenger front seat with a built-in seat belt and tumble function. All of these innovations are never-before-seen approaches for mass-produced vehicles, which allow us to realize a completely new style of car that focuses on universal design and is very user-friendly.

Tadakara, Takehiko, Miyamoto, Naokazu

Influence of Structural Foam Properties on the Performance of Automotive Body Reinforcements

2003-01-03263/3/2003

With the increasing demands on automakers to improve crash worthiness, and CAF requirements, automakers are faced with evaluating alternative technologies to achieve new competitive standards. In particular, the use of structural foam as a reinforcing media for automotive hollow sections is being examined. The objective of this study is to examine the use of epoxy structural foam in a hollow section as an optimum reinforcing means and to compare the reinforcing performance of a solid fill versus a laminate configuration and several approaches using steel alone. For this comparative program, idealized hat shaped cross sections are tested in three point bending. A quasi-static load-deflection curve is reported for each beam type. For crash-worthiness, strength and energy absorption is physically measured for an unfilled baseline beam and reinforced beams with the composite reinforcement in the middle third of the length of the beam. All beams were modeled using FEA failure analysis for the steel and the foam. Correlation was indicated for failure mode and load-deflection. The correlated model was used to conduct a sensitivity study for the carrier properties, the polymer thickness, and efficiencies using steel reinforcements alone. The result of this study indicates that section reinforcing efficiencies are achieved by not filling a section solid, using a local reinforcing laminate, and reconfiguring existing sheet metal to create a laminate thereby eliminating the need to add an additional metal reinforcement.

Wycech, Joe, Butler, Mark

The Ahmed Model Unsteady Wake: Experimental and Computational Analyses

2003-01-13153/3/2003

The unsteady wake of the Ahmed model has been investigated experimentally using time-accurate 5-hole and hot-wire probes and computationally using Exa PowerFLOW. The backlight angle was 25° which was chosen to be slightly below the critical angle observed computationally. The CFD results are similar to experimental results for backlight angles just below the critical angle (eg: 27.5°, 30°). Unsteady flow-field reconstruction of the experimental results and the CFD results both revealed a quasi-two-dimensional vortex-shedding type structure from the bottom of the model base. This results in a semi-periodic build up and collapse of the near wake and produces a symmetric oscillation in the strength and position of the rear pillar vortices. The period of this phenomenon corresponds to a Strouhal number of approximately 0.5 based on free-stream velocity and the square root of the model frontal area.

Sims-Williams, David B., Duncan, Bradley D.

Development of an Aerodynamic Prediction Using an Advanced Aerodynamic Panel Program

2002-01-20457/9/2002

An advanced panel method is presented for simulating the airflow of arbitrary three-dimensional automotive body in the paper. The theory is about a wake synthesizer for panel methods that use an iterative procedure to determine the position of strongly interacting vortex sheets. The estimation of the wake geometry is based on blunt body theory with separation flow. The method is applied to the A-pillar separation on foreside of an automobile and be fit for determine the starting point for a three-dimensional iterative solution. Comparison with experimental data shows that calculations results with the estimated wakes are more reality than with the attached flow

Zhengqi, Gu, Jun, Wu

Theoretic Analysis of Factor to Affect Door Closing Force by Positioning Error of Assembly Fixture

2002-01-07693/4/2002

In order to analyze positioning errors of assembly fixture of car SANTANA 2000, a 3D CAD model of fixture is built in this paper. Six typical deviation models are defined on the basis of six points positioning principle for fixture. The assembly gap distribution between door and side frame is analyzed and the influence of different deviation patterns on assembly gap is studied, and the effect of assembly gaps on door closing force is evaluated meanwhile. The results show that positioning errors of door assembly fixture is one of the most important factors to affect the door closing force.

Zhao, Jiancai, Zhu, Xunsheng, Wan, De'an

Distributive Lighting Systems for Interior Applications

2002-01-09793/4/2002

With the development of cars towards mobile offices and homes, people are spending more time inside their vehicle than ever before. Consequently, humanization of car interiors is becoming increasingly important to enhance the drivers' comfort and thereby his performance and safety. This is acknowledged by the car industry and has led to an increasing number of light outlets in the car interior over the last decade. Lighting plays a valuable role in the way the car's interior environment is perceived and this in turn determines the drivers' and passengers' comfort and safety. While up to now functional lighting applications (e.g. switch indicators and reading lamps) have dominated the car interior, these do not contribute significantly to its humanization. Ambient, orientation and contour lighting applications reveal the real value of a car's interior environment. Large-area plastic light guide devices enable us to combine several of the above mentioned interior lighting applications, e.g. ambient lighting and a reading spotlight, utilizing a build-in depth of only 6-8 mm. In this set-up, the ambient lighting function is served at luminance levels complying with the low glare requirements set for not disturbing the drivers' view. In another solution, an 80 – 150 lux reading spot illuminating an area of about an A3 size paper can be generated from the same device, using a single 16W bulb with integrated reflector. In this presentation we will elaborate on several examples of such distributive lighting systems.

‘Kim’ Jalink, C. J.

Theoretical Approach for Pillar Trim Design to Reduce Head Injury

2001-01-305610/16/2001

This paper presents an analytic method to estimate the proper space and stiffness of the vehicle's pillar trim to meet FMVSS 201 head injury criteria. A practical guideline curve, which is used in determining the adequate space and stiffness of pillar trim, is derived assuming haversine curve for the head impact pulse. Rib structure of pillar trim, which has a required stiffness, is designed using further simplification that models the BIW and the trim as equivalent springs. The required stiffness of the trim was achieved by adding a rib structure to it, and the shape of the rib structure was obtained using finite element analysis. Finite element analysis and experiment were conducted to validate the design of the trim, and the results were very close to the required stiffness.

Kim, Hyoung-Gon, Kim, Dong-Seok

PEDESTRIAN HEADFORM IMPACT TESTS FOR VARIOUS VEHICLE LOCATIONS

2001-06-01856/4/2001

Current accident analysis shows that the head of the pedestrian impacts most frequently into or around the windscreen since cars in recent have a short hood. Therefore, the injury risks to the head in contact with various locations of the car including the windscreen and its frame were examined on the basis of headform impact tests. The HIC is high from contact with the cowl, lower windscreen frame or A pillar, and it is low with increasing distance from these structural elements. In the windscreen center, the HIC is less than 500. The headform impact test results were compared between earlier and current car models. The HICs in the bonnet top area are similar in either type car except for the car built especially for pedestrian safety. However, on the A pillar, the HICs are much greater for current cars. From child headform impact tests for the WAD of 1000 mm, the HIC of SUV is higher than cars, and the SUV with steel bull bar leads to high injury risk.

Mizuno, Koji, Yonezawa, Hideki, Kajzer, Janusz

Head Injuries in Vehicle-Pedestrian Impact

2000-01-01573/6/2000

In vehicle-pedestrian impacts, the kinematics and severity of pedestrian injuries are affected by vehicle front shapes. Accident analyses and multibody simulations showed that for mini vans the injury risk to the head is higher, while that to the legs is lower than for bonnet-type cars. In mini-van pedestrian impacts, pedestrians ran high risks of a head impact against stiff structures such as windshield frames. When pedestrians are struck by a car with a short hood length, their heads are likely to strike into or around the windshield. The injury risks to the head by such an impact were examined by head form impact tests. The HIC rises from contact with the cowl, windshield frame or A pillar, and it lessens with increasing distance from these structural elements.

Mizuno, Koji, Kajzer, Janusz

Aerodynamic Noise Simulation based on Lattice Boltzmann Method ( Surface Pressure Fluctuations around A-pillar )

1999-01-11273/1/1999

1 A technique based on Lattice Boltzmann Method has been applied to the aerodynamic noise simulation by calculating the surface pressure fluctuations. In the first place, basic investigations were performed by using a simple geometry model (wedge box) that generated the flow structure similar to that of vehicle's A-pillar vortex. Then, the work was extended to an actual production vehicle's body. As a result, the tendency of the surface pressure fluctuations around A-pillar was captured. Consequently this method makes it possible to evaluate the complex flow pattern and the surface noise signature at the early exterior design phase without wind tunnel tests using prototype vehicles.

Uchida, Katsuya, Okumura, Kenji

Structure and Padding Optimization for Side Impact Protection

9861835/31/1998

This paper aims to show methods to design and optimize vehicle side structure and padding to improve side impact protection. To limit injuries at thorax level, intrusion profile during impact must perform a negative vertical tilt: a way to obtain this is to avoid B pillar deforming above R point. A static analysis may be useful to determine a proper distribution along B pillar axis of sections'' moments of inertia. A good structural behavior is necessary but not sufficient to perform good results in side impact. A proper control of padding stiffness is very important especially for abdomen protection. A method to evaluate the stiffness of padding at thorax level is proposed. A similar method is used to determine failure load of armrest for abdomen protection.

Di Leo, Marcello

Attributes of Nonwovens in the Headliner Molding Process

No longer are North American automotive OEMs designing vehicles for their own domestic market. Today's automotive engineer must design and deliver world class quality to a global customer with unprecedented expectations, unlimited choices and little brand loyalty. In automotive interiors, there are distinctions between vehicles designed in North America and their engineered counter-parts in Japan and Europe. One area worthy of examination is the selection of nonwoven automotive interior headliner fabrics. Japanese and European automotive OEM's have recognized nonwovens for their reduced cost, light weight, superior fade resistance and ability to be recycled. Today, nonwoven automotive interior headliner fabrics command over 60% of the Japanese and 50% of the European automotive markets, with less than 5% in North America. Due to limited Tier 1 supplier (molder) experience in North America, this paper will discuss the advantages of nonwovens from the perspective of experienced automotive headliner suppliers. These Japanese and North American molders supply both tricot knit/foam and nonwoven headliner fabric to automotive OEM's. In the global race to improve quality and increase productivity, this paper contends that nonwovens prevail over conventional tricot knit/foam headliner fabrics in a variety of processes.

Kitazawa, Norimitsu “Norm”, Preininger, William A., Karasawa, Naruyoshi “Kaz”

Effect of Front Seat Stiffness in Federal Dynamic Side Impact

9701262/24/1997

The objective of this research is to study the effect of front seat structure in Federal (FMVSS 214) dynamic side impact Finite Element Analysis (FEA) simulation. This research investigates the side structure behavior, buckling mode, velocity, and deformation of components such as the B-pillar, front door, rear door, floor pan, and rocker in three different configurations, using two different front seal stiffnesses. A methodology was developed to reduce side structure deformation and associated component velocities, thereby minimizing occupant loading.

Farahani, Akbar, Honken, Brian

Glass Drop Design for Automobile Windows - Design of Glass Contour, Shape, Drop Motion, and Motion Guidance Systems

This paper presents a new computerized approach for designing the automobile window glass contour, the glass drop motion, and the regulator systems. The three-dimensional geometrical relationship of the glass contour, the drop path, and its guidance system have been studied. Methods for barrel and helical drops are presented for optimizing the glass profile and drop path trajectories. Criteria for perfecting the glass contour are developed for shaping the profile of the vehicle clay model. Methods for correcting the glass contour and shape are presented. Examples are provided to illustrate how to improve the design. This approach integrates the development works of glass contour, drop motion and regulator systems. Through this design approach the window glass can fit and move perfectly in the door assembly.

Chang, H. Y., Song, Ji Oh

Computer-Aided 3-D Surface Reconstruction During High Speed Crush Events

2/1/1991

A system which can remotely measure detailed deformations of vehicle structures during crush events was developed. The system uses ordinary video or 16 mm high speed movie to capture the crush event. This information is digitized and analyzed using personal computers to perform photogrammetric manipulations which yield accurate surface geometries. The output is useful for comparison to computer simulations. This paper presents preliminary results regarding the accuracy of this system.

Karvelis, Albert V., Rogers, Michael W., Anderson, Carl E., Liubinskas, Aldis

Integrated Instrument Panels from Pillar to Pillar

90116410/1/1990

The concept of the Integrated Instrument Cluster is changing. The technology is advancing and the requirements moving forward. The way clusters are designed must move with the times.

Bodley-Scott, Jamie

On the Relation Between Continuing Engineering Education and Revitalizing the Automotive Industry of China

89137911/1/1989

China hasn't paid much attention to the importance of continuing engineering education (CEE) as CEE was studied in China much late. It's very important to probe into the relation between the auto development strategy of China and CEE. Here enough evidence can make an exposition that we must rely on CEE if we intend to develop the auto industry. If we, CEE staff of the auto industry want to develop the auto industry, we must set up the thought firmly for developing the auto industry and research how to service and study the inherent and relevant policies. The auto industry of China must be developed greatly because it has become the pillar industry of the Chinese national economy. So CEE which services for the auto industry also must be developed greatly. It's very important to solve the problem of understanding theoretically

Multi-Axial Collapse of Rectangular Section Tubes and Its Modelling in Finite Element Analysis

4/1/1988

The paper reviews the main results of the theoretical and experimental analysis of the multiaxial collapse modes in rectangular section tubes used in bus and other vehicle structures. The tubes were tested quasistatically to collapse under the uniaxial bending, biaxial bending, pure torsion, torsion combined with uniaxial bending and torsion combined with biaxial bending. Hinge characteristics under multiaxial loading were simulated by a combination of the uniaxial collapse data. The analytical model compared well with the experiments.

Todorovska-Azievska, L., Kecman, D.

Rollover and Interior Kinematics Test Procedures Revisited

86187510/27/1986

This paper reviews the development and demonstration of a procedure for a rollover test to be conducted without the use of a ramp or rollover cart and also demonstrates the kinematics of an unrestrained far side occupant during the rollover sequence. A full-size car was pulled sideways into an energy absorbing barrier causing the car to roll 180 degrees and yaw 360 degrees. The test demonstrated that in an event of this type and severity, the injury can occur prior to ejection and that there is no correlation between roof crush and injury.

Habberstad, John L, Wagner, Roger C., Thomas, Terry M.

Energy Absorption Material Selection Methodology for Head/A-Pillar

86188710/27/1986

The objectives of this paper are to establish a reasonable procedure for padding selection (for head/A-pillar protection) and to demonstrate how the procedure would be applied in a particular vehicle. The objectives are met by a four step procedure: 1. Theoretical analysis of material properties and the effect of padding materials on head responses, 2. Static or quasi-static and dynamic evaluations of the material properties, 3. Preliminary evaluation of the protective capabilities of the materials by simulated A-pillar component testing, and 4. Final evalution of the most promising material candidate by component testing the material installed on the upper A-pillar of a 1981 Chevrolet Citation.

Monk, Michael W., Sullivan, Lisa K.

The Development of a Vehicle Angled Side Collision Computer Simulation Program

8608224/22/1986

A computer simulation program (Ansimsim2) has been developed which is able to simulate the dynamics of an impacted vehicle in an angled side collision, i.e. to predict the rigid body motions and side structural deformations of the struck vehicle. It is a ‘mass-spring’ model of the impacting vehicle front end and impacted side structure interaction. Only the side structure stiffness characteristics of the impacted vehicle is taken into account as it's mass relative to the whole vehicle mass is negligible. General equations of motion, tyre and suspension data are used to simulate the rigid body motions of the impacted vehicle. The correlations of test with simulation results have been promising, bearing in mind the complex impact process and small use of computer resources.

Ng, Peter, Tidbury, Guy H.

Development of a Rigid Passenger Safety Compartment Made of Composite Material-Application for Front Door Frames

Based an extensive preparatory work and analyses, suggestions have been drawn up with regard to solutions for front door frames in the following regions:- door hinge mountings, seat belt anchorage mountings of B pillars, cross sections for the top of A pillars. At the same time as the design work, FEM calculations should be carried out to ensure optimization of the concepts. Economy reasons and experiences in production runs point towards a very strong fibre glass-reinforced door frames manufacutred in the SMC procress. The complete door frame is examined in comparison with geometrically similar sheet metal parts on a test frame and in the vehicle.

Voy, Christian, Morsch, Dieter

Development of a Computer Graphics Package for Displaying Static and Dynamic Analyses of Frame Structures

A computer graphics package for displaying the results of finite element calculations that model the nonlinear static and dynamic response of frame structures is presented. This package uses the public domain general purpose finite element code, ANSR, as the analysis package and the general purpose color graphics code, MOVIE.BYU, to display the results. Example results from both static and dynamic nonlinear calculations are presented using high quality graphics pictures.

Benzley, S. E., Stephenson, M. B., Balling, R. J., Anderson, D. O., Warner, C. Y.

Effectiveness of After Market Rust Protection

Many questions have been raised about the need for and effectiveness of aftermarket rust protection, but no clear and precise answers have originated from applicators or manufacturers of the products. This paper will address three major issues related to aftermarket rust protection: where to put the product, what product requirements are necessary, and how to apply the product. Product performance will be established by corrosion testing on uniprime, G90 galvanized, and production steel test panels, representative of the materials used by the auto industry. Application requirements will be established by comparing the more conventional holes-drilled method to the newer fogging procedures, showing the deficiencies of these fogging procedures. Finally, this paper will establish that aftermarket rust protection benefits the consumer provided the materials used are effective corrosion preventives, the application procedures assure total and uniform coverage, and the amount of material used related to the performance criteria of the product.

This paper investigates an alternate design for a small car with maximum interior space. The most advantageous design was found to be a three seater vehicle with a possible fourth seat. The driver is positioned in the center of the vehicle. All seats are movable front and aft and sideways and the trunk is variable giving maximum space utilization and versatility. The car has unique folding doors which swing up far into the roof for easy accessability to all seats. Space for 3 or 4 people is provided in a vehicle of less overall dimensions than current designs. Through use of plastic materials weight is also lower guaranteeing excellent fuel economy.

Strobel, Werner K., Strobel, Manfred H.

Datsun 280ZX – Integration of Aerodynamics and Appearance

It is essential for today’s sports car to have excellent aerodynamic characteristics and a sophisticated style. These factors are dependent and often inconsistent with each other. It is desirable that they are integrated rather than compromised in such cases. In the early stages of development of the 280ZX, we thoroughly investigated the relationship between a style and its aerodynamic characteristics. A three-dimensional smoke tunnel and a 1/5-scale model was used for this purpose. Several improvements were examined mainly on the front end of the model, which strongly affect both aerodynamic characteristics and styling, such as the hood, bumper, chin spoiler, engine-compartment opening and others. The resultant values of the principal aerodynamic coefficients of the realized 280ZX are CD=0.385, CLF=0.11 and CYM=0.04 (CD and CLF at a yaw angle of 0 degree and CYM at 10 degrees). In addition to the above-mentioned aerodynamic characteristics, wind noise, ventilation efficiency and engine-compartment cooling performance were also developed.

Yoshiyuki, Kazuhiko, Maeda, Tatsuo, Takagi, Michitoshi, Yanagawa, Motoo

Further Validation of the Simulation Model of Automobile Collisions Program

To improve the utility of the SMAC program and to assess its limitations, twelve vehicle-to-vehicle collisions were staged and then reconstructed with the program. A variety of impact configurations were run including: 60° front-to-side, 90° front-to-side, 10° offset head-on and 10° offset rear-end. The reconstruction of each test is discussed and compared with the measured data, using the final rest positions, velocity changes, and damage profiles of each vehicle. Finally, the limitations of the SMAC program together with recommendations for improving the simulation model are outlined.

Jones, Ian S., Baum, A. Stephen

Injury Mechanisms in Side Impact

Side impact accidents are the most severe and second frequent traffic accident configuration. By a comparison of results of tests with and without intrusion, this paper shows that the severity of side impact for the occupant seated near the impacted side is mainly due to intrusion of the side wall inside the car compartment of the struck car. Without intrusion, injury criteria recorded on a dummy are much lower than when there is intrusion. The influence of intrusion can be explained by the deformation speed of the side wall of the struck car. The velocity change of different parts of cars and of dummy have been determined in two tests conducted at 40 and 50 Kph. The diagrams of these velocity changes indicate that the door and the frame seat of the struck car sustain a velocity change higher than the car floor. The pelvis of the dummy seated near the impacted side sustains a velocity change in the same order of magnitude as the door, whereas its chest has a lower velocity change. This paper concludes that preventing from intrusion will decrease the severity of side impact and the seat can be used to participate in this stiffening. A padding should also be necessary but the determination of its characteristics needs a better knowledge of human tolerance to side impact.

Cesari, D., Ramet, M., Herry-Martin, D.

The Porsche 924 Body-Main Development Objectives

Functional design through aerodynamics, secondary safety, corrosion resistance, repairability, economic production and operation - such are the critical points to be observed during today's body development. The Porsche 924 realises these requirements by assuring simultaneously a high degree of functionality and economy.

Burst, Hermann E., Srock, Rainer

Manufacturing the Third Generation Econoline

This paper presents highlights of assembly operations for the new 1975 model Ford Econoline III. All major assembly operations are covered. However, particular emphasis is placed on the automation used in body assembly. Econoline body and paint operations are performed at Ford's Ohio Truck Plant. Painted bodies are transported via special vans to the Lorain Assembly Plant for trim, frame and final assembly operations.

Knighton, C. L.

Development of the First Sheet Molding Compound (SMC) Body Component: The Chrysler Station Wagon Air Deflector

The Chrysler Corporation made use of a thermosetting polyester sheet-molding-compound (SMC) to provide an efficient, neat-appearing, and economical station wagon air deflector for its 1969 full-size station wagons. This marked Chrysler's first usage of this material for a major automotive body component.

Currier, George J.

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