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Viewing 1 to 30 of 103994
2015-04-14
Technical Paper
2015-01-1516
Mohammed K Billal
The component level wheel crush test will help to predict the wheel crush load under static condition. In passenger car, the frontal wheel has to absorb the energy during the crush and it should not intrude more in to the occupant compartment. Using virtual tools, the wheel crush load can able to predict for the new designs and the new design changes can be made quickly to meet the requirement. During the wheel crush, the crack will initiate and propagate, then the major failure will occur. In virtually, this failure can be achieved using progressive damage and failure material model. This material model is having the capability to predict the damage initiation due to the ductile and shear failure. After damage initiation, the material stiffness is degraded progressively according to the specified damage evolution response. The progressive damage models allow for a smooth degradation of the material stiffness, in both quasi-static and dynamic situations.
2015-04-14
Technical Paper
2015-01-1517
David Stalnaker, Ke-Jun Xie, Terence Wei
Tire manufacturers need to perform various types of testing to determine tire performance under representative vehicle load conditions. However, test results are influenced by a number of external variables other than tire construction. Vehicle load distribution and suspension properties are some of those external variables which can have a significant effect on tire wear rate and durability. Therefore, in order to measure tire performance in a controlled and repeatable manner, a representative vehicle and associated tire load conditions are needed. Laboratory or indoor tire testing offers many advantages over vehicle fleet testing. It provides a well-defined test environment and repeatable results without influence from external factors. Indoor testing has been largely developed around the process of simulating tire wear performance on a specific reference vehicle, including its specific weight distribution, suspension characteristics, and alignment.
2015-04-14
Technical Paper
2015-01-1512
Sairom Yoo, Md Salah Uddin, Hyeonu Heo, Jaehyung Ju, Doo Man Kim, Seok-Ju Choi
In an effort to develop tires with low rolling resistance, nonpneumatic tires (NPTs) with low viscoelastic energy loss materials are receiving more attention. For better design of NPTs for better fuel efficiency, one may need to analyze rolling energy loss of NPTs at a component level. The objective of this study is to develop a tool to quantify rolling energy loss and thermal dissipation of NPTs at a component level. For varying vehicle loads and rolling speeds, we suggest a thermo-mechanical model of an NPT with hexagonal cellular spokes to investigate temperature distribution of the NPT caused by hysteresis and convection loss into air. Using a hyper-viscoelastic model developed from a uniaxial (tensile and compression) testing and dynamic mechanical analysis (DMA), a thermo-mechanical model is developed by combining longitudinal shear deformation induced hysteresis and cooling to air.
2015-04-14
Technical Paper
2015-01-1510
Edoardo Sabbioni, Davide Ivone, Francesco braghin, Federico Cheli
Estimation of friction coefficient and sideslip angle represents a key-point for improving control systems for vehicle safety, e.g. ESP (Electronic Stability Control), VDC (Vehicle Dynamics Control), etc. A model-based approach (state observer or Kalman filter) is generally used on purpose. Benefits induced by in-tyre sensors on sideslip angle and friction coefficient estimation are investigated in this paper. Thus tyre cornering force measurements are added to the ones usually present on-board vehicle (steer angle, lateral acceleration and yaw rate) and used to implement an Extended Kalman Filter (EKF) based on a single-track vehicle model. Tyre-road contact forces are assumed to be provided once per wheel turn by a smart tyre constituted of two tri-axial accelerometers glued on the tyre inner liner. Performance of the proposed observer is evaluated on a series of handling maneuvers and its robustness to road bank angle and tyre/vehicle parameters variation is discussed.
2015-04-14
Technical Paper
2015-01-1505
Ibrahim A. Badiru
Vehicle pull is a condition experienced by customers where a constant torque at the steering wheel is required to maintain the vehicle on a straight path. Vehicle lead is a condition where a non-zero steering wheel angle is required to maintain a straight path. There are many potential causes for vehicle pull or lead—road condition, suspension asymmetry, and tire characteristics to name a few. Both vehicle pull and lead can cause customer dissatisfaction with the vehicle as well as drive OEM warranty service costs. Electronic Power Steering (EPS) systems have overtaken Hydraulic Power Steering (HPS) as the predominate steering architecture for new passenger vehicles. One of the key benefits of EPS is the ability to program value added features (VAF) into the EPS controller. These features can significantly enhance the pleasure and safety of the driving experience for the customer. EPS pull compensation is a feature that reduces the driver workload to compensate a vehicle pull.
2015-04-14
Technical Paper
2015-01-1504
Ning Wei Bao
A ball screw regenerative shock absorber was designed for the relief of the vehicle vibration and the energy recovery of the vehicle vibration. The effect of its main parameters on the suspension system was numerically analyzed. According to the principle of the ball screw regenerative suspension system, a mathematical model of the ball screw regenerative shock absorber was established regarding the ball screw rotational inertia, the motor rotational inertia, the screw lead and the radius of the screw nut. A suspension dynamic model based on the ball screw regenerative shock absorber was developed combining the road model and the two-degrees-of-freedom suspension dynamic model.
2015-04-14
Technical Paper
2015-01-1501
Ryusuke Hirao, Kentaro Kasuya
Many electronic control components have been introduced into vehicles with the aims of improving their safety and comfort, and saving energy. Various suspension systems have been developed, to reconcile ride feeling with control stability at a high level. Development efforts have been particularly active in the field of semi-active suspension, prompted by its superior energy-saving and cost performance. Algorithm which is based on skyhook control has been applied mostly to the ride comfort control of semi-active suspension system of vehicle. Also, at the time of steering, control for enhancing damping force are commonly used as handling control to restrain transitional roll angle. Therefore, in this development we developed new ride comfort control and new handling control, and constructed a system which uses only vehicle height sensor as dedicated sensor and uses damping force variable damper of pressure control type.
2015-04-14
Technical Paper
2015-01-1497
Hideaki Shibue, Devesh Srivastava
Torsion beam suspensions are lightweight and low-cost, and they are therefore frequently used for the rear of small front-wheel drive vehicles. The configuration of the suspension is simple and it comparatively consists of fewer components. However, it is difficult to predict their characteristics and satisfy the target of the performance in the early stages of development in particular, because it should realize the various performance elements demanded of a suspension in a single part. A great deal of research has been conducted on the cross-sectional shape of the beam section, but up to the present there has been almost no discussion of the effect of property of the trailing arms on suspension characteristics. This paper discusses tests conducted to study the effect of the rigidity of the trailing arms, and considers the mechanism of that effect.
2015-04-14
Technical Paper
2015-01-1491
Automotive OEMs, insurance agencies and regulatory bodies are continuously looking at various accident statistics and proper ways of evaluating unaccounted (as per current regulations and safety ratings) accident scenarios to improve the safety standards of cars. Small overlap and oblique impacts during which a corner of a car hits a tree or the corner of another vehicle are two such situations. To address these scenarios, IIHS has incorporated small overlap impact in the NCAP rating. Similarly, NHTSA is developing an oblique test to address this. Most of the vehicles which are on road scored low when tested for these impact scenarios. This is mainly because most of the energy-absorbing structures (in a vehicle) such as rails and crush boxes during a high speed crash do not get engaged with the impactor as the overlap is very small.
2015-04-14
Technical Paper
2015-01-1489
Transfer or response equations are important as they provide relationships between the responses of different surrogates under matched, or nearly identical loading conditions. In the present study, transfer equations for different body regions were developed via mathematical modeling. Specifically, validated finite element models of the age-dependent Ford human body models (FHBM) and the mid-sized male Hybrid III (HIII50) were used to generate a set of matched cases (i.e., 192 frontal sled impact cases involving different restraint, impact speeds, severities, and FHBM age). For each impact, two restraint systems were evaluated: a standard three-point vehicle belt with and without a single-stage inflator airbag. Regression analyses were subsequently performed on the resulting FHBM- and HIII50-based responses. This approach was used to develop transfer equations for seven different body regions: the head, neck, chest, pelvis, femur, tibia, and foot.
2015-04-14
Technical Paper
2015-01-1492
Kazunobu Ogaki, Takayuki Kawabuchi, Satoshi Takizawa
We test the mid-size sedan according to NHTSA Oblique test to assess the occupant protection and to provide possible design changes to improve the oblique collision performance. This test result predicted high potential injury for BrIC, chest deflection, and lower extremities. Injury reductions could likely be achieved through optimization of the restraint devices. We focus to reduce the lower extremity injury. Traditionally, lower extremity injuries are often mitigated by reducing the intrusion of the cabin’s dashboard lower region; however, this type of design change can lead to a significant increase in vehicle weight. Increasing the energy absorbed within the engine compartment is more efficient than reinforcing the passenger compartment.
2015-04-14
Technical Paper
2015-01-1490
Tony R. Laituri, Scott Henry, Kaye Sullivan
A study of belted driver injury in various types of frontal impacts in the US field data was conducted. Specifically, subject to the Frontal Impact Taxonomy of Sullivan et al. (2008), injury potential of belted drivers in non-rollover, frontal impacts in the National Automotive Sampling System (NASS) was assessed. The field data pertained to 1985 - 2013 model-year light passenger vehicles in 1995 - 2012 calendar years of NASS. Two levels of injury were considered: AIS2+ and AIS3+. For ease of presentation, we grouped the injury data into lower- or upper-body regions. Frontal impacts were binned into eight taxonomic groups: Full-engagement, Offset, Narrow, Oblique, Side-swipe corner, High/low vert (i.e., over- and under-ride crashes), DZY-No rail (i.e., distributed crashes, but with negligible frame rail involvement), and Other. The results of the survey yielded insights into the distribution of belted-driver injury in NASS.
2015-04-14
Technical Paper
2015-01-1488
Adam G.M. Cook, Moustafa El-Gindy, David Critchley
This work investigates the multi-objective optimization methods for Front Underride Protection Devices (FUPDs) using varying meta-modeling and direct optimization techniques, while implementing several materials and minimizing cost of the design. The developed dsFUPD F9 design for a Volvo VNL was subjected to a modified ECE R93 quasi-static loading to objectify deformations. A developed application was needed to objectify the cost as a third target objective to minimize with mass and deformation of the design. NSGA-II, SPEA-II genetic algorithms and adaptive simulated annealing optimization methods were under investigation in combination with three meta-modeling techniques; Feedforward Neural Network, Radial Basis Function Network, and Kriging. Leapfrog LFOPC algorithm hybridized forms of genetic algorithms and adaptive simulated annealing was also investigated.
2015-04-14
Technical Paper
2015-01-1486
Craig A. Markusic, Ram Songade
Full vehicle crash simulations typically require several days of effort from a highly skilled FE (finite element) analyst to set-up, execute, and analyze. The goal of this project was to create a simplified FE model of a side crash utilizing the same sophisticated software (LS-DYNA) that the FE analysts use along with a custom graphical user interface (GUI) that will allow an inexperienced user to set-up, execute, and analyze a number of side impact scenarios in a matter of hours, not days, and with very little training. The GUI allows the user to easily modify the performance characteristics of the side impact system that are critical to side crash performance including but not limited to intrusion rate, door liner stiffness, side airbag stiffness, side airbag time to fire, etc. The user can then compile and submit the model with a few simple clicks of a button.
2015-04-14
Technical Paper
2015-01-1523
Takahiro Uesaka, Tatsuya Suma
Simulating road noise while a vehicle is operating shortens the development period and reduces the number of prototypes, which lowers development costs. Realizing road noise simulation identifies the force transmitted to the suspension through the tires and wheels from vibration between the road surface and the tires. There are significant variations between static state characteristics and vibration characteristics of tires in motion, which are challenging to measure. The effects of reduction of the elastic modulus of the rubber in the tires due to repeated loads accompanying contact with the ground, and of Coriolis and centrifugal forces resulting from the rolling motion are known. Detailed analysis of the eigenvalue fluctuations produced by Coriolis force based on measurements taken using sensors installed inside the tires has recently been reported. Knowledge is still lacking in areas such as the specifics of how the input from the tires changes due to these fluctuations.
2015-04-14
Technical Paper
2015-01-1518
Emmanuel O. Bolarinwa, Oluremi Olatunbosun
Three-dimensional (3D) Finite element (FE) tyre models have been widely used for tyre design, vehicle design and dynamic investigations. Such tyre models have the inherent advantage of covering a wide range of tyre modelling issues such as the detailed tyre geometry and material composition, in addition to an extensive coverage of tyre operational conditions such as the static preload, inflation pressure and driving speed. Although tyre vibration behaviour, in different frequency ranges are of general interest, both for the vehicle interior and exterior noise, the present study is limited to a frequency of 100 Hz which is prevalent in most road induced NVH ride and handling problems. This study investigates tyre vibration behaviour using a propriety FE code. Such investigation plays an important role in the study of vehicle dynamics.
2015-04-14
Technical Paper
2015-01-1439
Toshiyuki Yanaoka, Yasuhiro Dokko, Yukou Takahashi
To evaluate vehicle safety performance for Traumatic Brain Injuries (TBIs) in crashes, comprehensive injury criteria is required. Few research results for injury criteria focused on Diffuse Axonal Injury (DAI) in crashes or pedestrian impacts exist. We developed injury criteria based on the rotational rigid body motion of the head for occupant and pedestrian crashes. We used the mid-sized male human head/brain FE model to investigate correlation between injury criteria based on the rotational rigid body motion of the head and intracranial responses related to DAI. The input pulses applied to the skull of the head/brain model were determined from the head acceleration data, and articulated rigid body simulation results of frontal occupant and pedestrian crashes. Results showed low applicability of the injury criteria to pedestrian impacts, presumably due to the maximum rotational velocity occurring before head contact to the vehicle.
2015-04-14
Technical Paper
2015-01-1442
Wolfgang Sinz, Jörg Moser, Christoph Klein, Robert Greimel, Karsten Raguse, Class Middendorff, Christina Steiner
Precise three-dimensional dummy head trajectories during crash tests are very important for vehicle safety development. To determine precise trajectories with an accuracy of approximately 5 millimetres, three-dimensional video analysis is an approved method. Therefore the tracked body is to be seen on at least two cameras during the whole crash term, which is often not given (e.g. head dips into the airbag). This non-continuity problem of video analysis is surmounted by numerical integration of differential un-interrupted electrical rotation and acceleration sensor signals mounted into the tracked body. Problems of this approach are unknown sensor calibration errors and unknown initial conditions, which result in trajectory deviations above 10 centimetres.
2015-04-14
Technical Paper
2015-01-1430
Brian Gilbert, Joseph McCarthy, Ron Jadischke
Objectives: The analysis and modeling of vehicle crush in accident reconstruction has traditionally been based upon the use of linear crush-based, stiffness coefficients. Recent research has allowed for the calculation and implementation of non-linear crush coefficients. Through the use of Engineering Dynamics Corporation (EDC) accident reconstruction software Human-Vehicle-Environment (HVE), which contains the collision algorithm called DyMESH (DYnamic MEchanical SHell), these coefficients have increased the accuracy of predicted crash pulse data. Research on non-linear crush coefficients thus far has been limited to frontal impacts into rigid barriers. Side Impact tests are typically more complex than a frontal collision testing. One form of side impact tests involve a Moving Deformable Barrier (MDB) impacting a stationary subject vehicle at a crab angle of 26-27 degrees.
2015-04-14
Technical Paper
2015-01-1421
Dennis Turriff, David J. King, James Bertoch
Vehicle rollovers generate complicated damage patterns as a result of multiple vehicle-to-ground contacts. The goal of this work was to isolate and characterize specific directional features in coarse- and fine-scale scratch damage generated during a rollover crash. Four rollover tests were completed using stock 2001 Chevrolet Trackers. Vehicles were decelerated and launched from a rollover test device to initiate driver’s side leading rolls onto concrete and dirt surfaces. Gross vehicle damage and both macroscopic and microscopic features of the scratch damage were documented using standard and macro lenses, a stereomicroscope, and a scanning electron microscope (SEM). The most evident indicators of scratch direction, and thus roll direction, were accumulations of abraded material found at the termination points of scratch-damaged areas.
2015-04-14
Technical Paper
2015-01-1428
Shane Richardson, Andreas Moser, Tia Lange Orton, Roger Zou
Currently techniques that can be used to evaluate and analyse lateral impact speeds of vehicle crashes with poles are based on measuring the deformation crush and using lateral crash stiffness data to estimate the impact speed. However, in some cases the stiffness data is based on broad object side impacts rather than pole impacts. The premise is that broad object side impact tests can be used for narrow object impacts; previous authors have identified the fallacy of this premise. Publicly available pole crash test data is evaluated. A range of simulated pole impact tests at various speeds and impact angles are conducted on validated publicly available Finite Element Vehicle models of a 1991 Ford Taurus, a 1994 Chevrolet C2500 and a 1997 Geo Metro (Suzuki Swift), providing a relationship between impact speed, crush depth and impact angle. This paper builds on previous publications and contains additional pole tests and new Finite Element Analyses.
2015-04-14
Technical Paper
2015-01-1482
Bisheshwar Haorongbam, Anindya Deb, Clifford Chou
Hat-sections, single and double, made of steel are frequently encountered in automotive body structural components. These components play a significant role in terms of impact energy absorption during vehicle crashes thereby protecting occupants of vehicles from severe injury. However, with the need for higher fuel economy and for compliance to stringent emission norms, auto manufacturers are looking for means to continually reduce vehicle body weight either by employing lighter materials like aluminum and fiber-reinforced plastics, or by using higher strength steel with reduced gages, or by combinations of these approaches. Unlike steel hat-sections which have been extensively reported in published literature, the axial crushing behavior of hat-sections made of fiber-reinforced composites may not have been adequately probed.
2015-04-14
Technical Paper
2015-01-1483
Anindya Deb, N Shivakumar, Clifford Chou
Rigid polyurethane (PU) foam finds wide applications as a lightweight material in impact safety design such as improving occupant safety in vehicle crashes. The two principal reacting compounds for formulating such a foam are variants of polyol and isocyanate. In the present study, an alternative mechanical engineering-based approach for determining, with confidence, the desirable ratio of reacting compounds for formulation of a rigid/crushable PU foam for mechanical applications is demonstrated. According to the present approach, PU foam samples are prepared by varying the mixing ratio over a wide range. The desirable mixing ratio is shown to be the one that optimizes key mechanical properties under compression such as total absorbed energy, specific absorbed energy and energy absorption efficiency.
2015-04-14
Technical Paper
2015-01-1469
Yan Wang, Taewung Kim, Yibing Li, Jeff Crandall
The characteristic of neck plays an important role on the kinematics and injury of pedestrian’s neck and head during the impact with vehicle, and the accuracy of the mathematical model affects the analysis results directly. A new mathematical pedestrian model has been developed in University of Virginia (UVA), which combines the advantages of both TNO facet occupant model and the lower extremity with more accuracy of biomechanical characteristics. So in this new pedestrian model, the occupant’s facet neck model developed by TNO is used to evaluate the pedestrian’s kinematics and dynamic response. Since the neck is special developed for occupants, the mechanical characteristics for lateral impact may not as good as that of frontal impact.
2015-04-14
Technical Paper
2015-01-1473
Kalu Uduma
The National Highway Transportation Safety Administration (NHTSA) issued the FMVSS 226 ruling in 2011. It established test procedures to evaluate ejection mitigation countermeasures that are intended to help minimize the likelihood of a complete and/or partial ejection of vehicle occupants through the side windows during rollover or side impact events. One of the countermeasures that may be used for compliance of this new safety ruling is a deployable restraint; specifically a Side Airbag Inflatable Curtain (SABIC). This paper discusses how three key phases of the optimization strategy in the Design for Six Sigma (DFSS), namely, Identify; Optimize and Verify (I_OV), were implemented in CAE to develop an improved simulation response, with respect to the FMVSS 226 test requirements of a SABIC. The simulated SABIC system is intended for a generic SUV and potentially also for a generic Truck type vehicle.
2015-04-14
Technical Paper
2015-01-1475
Alan F. Asay, Jarrod Carter, James Funk, Gregory Stephens
A follow-up case study on rollover testing was conducted with an instrumented single full-size SUV under real-world conditions. The purpose of this study was to conduct a well-documented rollover event that could be utilized in evaluating various reconstruction methods and techniques over the phases associated with rollover accidents. The phases documented and discussed inherent to rollovers are: loss-of-control, trip, and rolling phases. With recent advances in technology, new devices and techniques were implemented to capture and document the events surrounding a vehicle rollover. These devices and techniques are presented and compared with previous test methodology. In this case study, an instrumented 1996 GMC Jimmy SUV was towed to speed and then released. A steering controller steered the vehicle through maneuvers intended to result in rollover. The SUV experienced two non-rollover events before the vehicle finally rolled 1-1½ times.
2015-04-14
Technical Paper
2015-01-1461
Dietmar Otte
During most pedestrian-vehicle crashes the car front impacts the pedestrian and the whole body wraps around the front shape of the car. Meanwhile the windscreen is tested in NCAP conditions. The severity of injuries is influenced by car impact speed; type of vehicle; stiffness and shape of the vehicle; nature of the front (such as the bumper height, bonnet height and length, windscreen frame); age and height of the pedestrian; and standing position of the pedestrian relative to the vehicle front. The socalled Wrap Around Distance WAD is one of important measurement for the assessment of protection. For the study accidents with pedestrians and bicyclists are used for the analysis, how good is the WAD for injury prediction. GIDAS (German In-Depth-Accident-Study) collects accidents as representative sample of the German accident situation based on in-depth-investigation.
2015-04-14
Technical Paper
2015-01-1462
Seung Jun YANG
Euro-Ncap committee has been adopted overall impact star-grade system after 2009 and strengthening pedestrian protection cut-off score to obtain best impact-star grade until 2016. It is very difficult target to pass enhanced pedestrian cut-off score due to previous method. In this paper, I studied where is pedestrian weak area and why pedestrian injury is so high at that area based on our test result. I compared long-hood, 3 corner pop-up hood and pedestrian air-bag system. Finlly I suggest 3-corner rear-ward hood pop-up system is best method to meet our Impact new target in considering pedestrian protection ability, cost &weight.
2015-04-14
Technical Paper
2015-01-1463
In Hwang, Jisung Ryu, Jinho Kim, Jeahong Choi, Junho Lee
Injuries of occupants in a vehicle have been decreased considerably. However, efforts for protection of pedestrians are still insufficient and so as to satisfy enhanced regulation, pedestrian protection has been an important issue to get a high NCAP rating. These days, many advanced industries are striving for a better protection of pedestrians by using an active hood system. The active hood system is designed for reducing head injury of pedestrian. The most important part of an active hood system is sensor & ECU. In this paper we discuss the fiber optical sensor with membrane switches to detect pedestrians
2015-04-14
Technical Paper
2015-01-1465
Sho Nikaido, Shota Wada, Yasuhiro Matsui, Shoko Oikawa, Toshiya Hirose
1. Background and purpose There are various contributing factors to accidents of bicycles, it is considered that cyclists often do not observe the traffic regulation that requires cyclists to stop before a stop line at an intersection. As a countermeasure to this type of accident, cycling assist systems that activate a warning system for cyclists have been researched and developed. This assist system warns the cyclist about the danger of a collision. Such an assist system needs to provide a warning with appropriate timing. It is necessary to clarify cycling characteristics in developing a countermeasure for traffic accidents at an intersection without signals. The findings of this study can be used for the future construction of an assist system that will encourage cyclists to observe traffic regulations.
Viewing 1 to 30 of 103994