Display:

Results

Viewing 181 to 210 of 15794
Technical Paper
2014-04-01
Yukou Takahashi, Miwako Ikeda
Abstract The validity of evaluating FlexPLI peak injury measures has been shown by the correlation of the peak measures between a human FE model and a FlexPLI FE model. However, comparisons of tibia bending moment time histories (BMTHs) between these models show that the FlexPLI model exhibits a higher degree of oscillatory behavior than the human model. The goal of this study was to identify potential improvements to the FlexPLI such that the legform provides more biofidelic tibia BMTHs at the normal standing height. Impact simulations using a human FE model and a FlexPLI FE model were conducted against simplified vehicle models to compare tibia BMTHs. The same series of impact simulations were conducted using the FlexPLI models that incorporated potential measures to identify measures effective for further enhancement of the biofidelity. An additional analysis was also conducted to investigate the key factor for minimizing the oscillation of the tibia BMTH. The results of this study showed that the change of the mass distribution between the bony and flesh parts, along with the addition of the mass compensating for the upper body, provide more biofidelic FlexPLI tibia BMTHs, when used at the normal standing height.
Technical Paper
2014-04-01
Kambiz Jahani, Sajjad Beigmoradi
Abstract Adequate visibility through the automobile windscreen is a critical aspect of driving, most often at very low temperatures when ice tends to be formed on the windscreen. The geometry of the existing defroster system needs to be improved in the vehicles, with the main aim of substantial increase in air mass flow reaching the windscreen through defroster nozzles and appropriate velocity distribution over the windscreen, while respecting all packaging constraints. The reason of this study is to investigate the windscreen deicing behavior of a vehicle by means of Computational Fluid Dynamics (CFD) with the main concern of improving deicing process by design an appropriate defroster. Two different defrosters with completely different geometry are considered for this purpose. A detailed full interior model of an existing vehicle is created via CAE tools. A transient simulation is performed and results are extracted to show how a proper design of the defroster will lead to considerable improve in deicing process.
Technical Paper
2014-04-01
Sanjeev Kumar, Rahul Bettakote, Pinak Deb
Abstract Offset crash compliance of a compact car is severe due to the compact layout and stringent fuel economy, weight and cost targets. Scope of the current work is to improve the structural crash performance of a compact car through CAE, in order to meet the offset frontal crash requirements as per ECE R94 Regulation. The project has been classified in three main phases. First phase includes the evaluation of baseline vehicle in CAE. In order to ensure the accuracy of CAE prediction, a methodology for predicting Spotweld rupture was implemented. Using this methodology, it is possible to find out the location and time of spotweld rupture as well as propagation of spotweld rupture in CAE. CAE results of spotweld rupture prediction showed good agreement with the physical test. In second phase, design iterations were carried out in order to meet the performance targets of structural deformation. At critical locations of spotweld rupture, spotwelds were reinforced by addition of arc welds tugs and bolts.
Technical Paper
2014-04-01
Bryan Styles, Jeffrey Santrock, Curtis Vincent, Michael Leffert, Narasimha Putcha
An evaluation methodology has been developed for assessing the suitability of R-1234yf in vehicles. This relates primarily to evaluating the flammability of R-1234yf in the engine compartment during a frontal collision. This paper will discuss the process followed in the methodology, the technical rationale for this process, and the results of the analysis. The specific types of analysis included in the methodology are: exhaust-system thermal characterization, computer simulated crash tests, actual crash tests, teardown and examination of crashed parts, and releases of refrigerant onto hot exhaust manifolds. Each type of analysis was logically ordered and combined to produce a comprehensive evaluation methodology. This methodology has been applied and demonstrates that R-1234yf is difficult to ignite when factors that occur in frontal crashes are simultaneously considered. Factors considered in this analysis include: crush and deformation of the vehicle structure, airflow in the engine compartment, exhaust system temperatures during different driving scenarios, and coolant release due to damage of the engine coolant system.
Technical Paper
2014-04-01
Sanjeev Kumar, Deepak Katyal, Amit Singh
Abstract Recent advancement in numerical solutions and advanced computational power has given a new dimension to the design and development of new products. The current paper focuses on the details of work done in order to improve the vehicle performance in Offset deformable Barrier (ODB) crash as per ECER-94. A Hybrid approach involving the Structural Crash CAE as well as Multi-body Simulation in MADYMO has been adopted. In first phase of the development, CAE results of Structural deformation as well as Occupant injury of the baseline model were correlated with physical test data. The second phase includes the improvement in intrusion and crash energy absorption by structural countermeasures in the vehicle body. In third phase parametric study has been carried out via Madymo simulation in order to decide on the factors which can be controlled in order to mitigate the Occupant injury. Recommendations of Madymo simulation have been confirmed by conducting Physical sled tests. Finally a cost and weight effective countermeasure package which involves the modification in Body structure and Restraint system has been developed in order to comply with the ECE R-94 offset crash regulation.
Technical Paper
2014-04-01
Alan R. Wedgewood, Patrick Granowicz, Zhenyu Zhang
Abstract Materials used in automotive components play a key role in providing crash safety to passengers and pedestrians. DuPont's lightweight hybrid material technology, which combines injection molded fiber reinforced plastics with drape molded woven composite materials, provides safety engineers with stiff energy absorbing alternatives. In an effort to validate the hybrid material's crash performance while avoiding expensive crash testing, numerical tools and methodologies are applied in evaluation of a hybrid composite test beam. Multi-scale material models capturing nonlinear strain-rate dependency, anisotropic characteristics, and failure criteria, are calibrated on a fiber reinforced plastic and a woven fabric. The fiber orientation and warp/weft angles were extracted from injection and drape molding simulation. The material laws and orientation information are coupled in a single finite element analysis to predict the performance of the hybrid composite beam under a dynamic three point bending load.
Technical Paper
2014-04-01
David LeBlanc, Mark Gilbert, Stephen Stachowski, Rini Sherony
Pre-collision systems (PCS) use forward-looking sensors to detect the location and motion of vehicles ahead and provide a sequence of actions to help the driver either avoid striking the rear-end of another vehicle or mitigate the severity of the crash. The actions include driver alerts, amplification of driver braking as distance decreases (dynamic brake support, DBS), and automatic braking if the driver has not acted or has not acted sufficiently (crash imminent braking, CIB). Recent efforts by various organizations have sought to define PCS objective test procedures and test equipment in support of consumer information programs and potential certification. This paper presents results and insights from conducting DBS and CIB tests on two production vehicles sold in the US. Eleven scenarios are used to assess the systems' performance. The two systems' performance shows that commercial systems can be quite different. Also demonstrated is the experience with test equipment, including a towable target that has been designed for resiliency and radar signature, a braking robot, and bumper guard.
Technical Paper
2014-04-01
Chi-Chun Yao, Jin-Yan Hsu, Yu-Sheng Liao, Ming Hung Li
Abstract Vehicle Rollover Prevention/Warning Systems have recently been an important topic in Advanced Driver Assistance Systems (ADAS) of automotive electronics field. This paper will propose a rollover-prevention system implementation with vehicle dynamic model, video-detection technique and rollover index to help the driver avoid accidents as driving into a curve. Due to the reason that vehicle rollover motion analysis needs complicated computation and accurate parameters of vehicle stability in real time, in the first stage a vehicle dynamic model based on Extended Kalman Filter (EKF) algorithm is built, which can estimate vehicle roll/yaw motion in the curve by vehicle sensors. And then the image-based technique will be employed in detecting the front road curvature, and combined in the system to predict vehicle steering status. The final stage is to apply the vehicle rollover index with estimated vehicle motion to predict the dangerous level to drivers for warning. In the system validation, a Digital Signal Processor (DSP) with Microcontroller Unit (MCU) hardware structure is equipped and implemented in our vehicle experimental platform.
Technical Paper
2014-04-01
Cheng-Lung Lee, Hongyi Zhang, Hong Nguyen, Yu-Ting Wu, Christopher Smalley, Utayba Mohammad, Mark J. Paulik
Abstract A novel multi-modal scene segmentation algorithm for obstacle identification and masking is presented in this work. A co-registered data set is generated from monocular camera and light detection and ranging (LIDAR) sensors. This calibrated data enables 3D scene information to be mapped to time-synchronized 2D camera images, where discontinuities in the ranging data indicate the increased likelihood of obstacle edges. Applications include Advanced Driver Assistance Systems (ADAS) which address lane-departure, pedestrian protection and collision avoidance and require both high-quality image segmentation and computational efficiency. Simulated and experimental results that demonstrate system performance are presented.
Technical Paper
2014-04-01
Louis Tijerina, James Sayer
Abstract The objectives of this study were a) to determine how expert judges categorized valid Integrated Vehicle-Based Safety Systems (IVBSS) Forward Collision Warning (FCW) events from review of naturalistic driving data; and b) to determine how consistent these categorizations were across the judges working in pairs. FCW event data were gathered from 108 drivers who drove instrumented vehicles for 6 weeks each. The data included video of the driver and road scene ahead, beside, and behind the vehicle; audio of the FCW alert onset; and engineering data such as speed and braking applications. Six automotive safety experts examined 197 ‘valid’ (i.e., conditions met design intent) FCW events and categorized each according to a taxonomy of primary contributing factors. Results indicated that of these valid FCW events, between 55% and 73% could be considered ‘nuisance alerts’ by the driver. These were the FCW alerts presented in benign conditions (e.g., lead-vehicle turning) or as a result of deliberate driver action (aggressive driving).
Technical Paper
2014-04-01
Edgar Yoshio Morales Teraoka, Shin Tanaka, Tsutomu Mochida
Abstract We develop a simulation tool which reproduces lane departure crashes for the purpose of estimating potential benefits of Lane Departure Warning (LDW) systems in the American traffic environment. Tools that allow a fast evaluation of active safety systems are useful to make better systems, more effective in the real world; however accuracy of the results is always an issue. Our proposed approach is based on developing a simulation tool that reproduces lane departure crashes, then adding the effect of the LDW to compare the cases with and without the safety system, and finally comparing the results of different settings of the safety system. Here, the accurate reproduction of the relevant crashes determines the reliability of the results. In this paper, we present the reproduction of the lane departure crashes occurred in American roads in one year, by using data distributions obtained from retrospective crash databases. We analyze data from NASS/GES1 and NASS/CDS2 to obtain the characteristics of lane departure accidents in the USA.
Technical Paper
2014-04-01
Gauri Ranadive, Anindya Deb, Bisheshwar Haorongbam
Abstract Load cells and accelerometers are commonly used sensors for capturing impact responses. The basic objective of the present study is to assess the accuracy of responses recorded by the said transducers when these are mounted on a moving impactor. In the present work, evaluation of the responses obtained from a drop-weight impact testing set-up for an axially loaded specimen has been carried out with the aid of an equivalent lumped parameter model (LPM) of the set-up. In this idealization, a test component such as a steel double hat section subjected to axial impact load is represented with a nonlinear spring. Both the load cell and the accelerometer are represented with linear springs, while the impactor comprising a hammer and a main body with the load cell in between are modelled as rigid masses. An experimentally obtained force-displacement response is assumed to be a true behavior of a specimen. By specifying an impact velocity to the impactor as an initial condition and using an implicit time integration technique, it is shown that the model accurately reproduces the input load-displacement behavior of the nonlinear spring corresponding to the tested component.
Technical Paper
2014-04-01
Prasad Rao Yerraguntla, Shashi Kulkarni, Deepak Asthana
Abstract Automotive Audio Signaling system is very vital and is controlled by local regulatory requirements. In India, usage of horn is very frequent due to highly congested traffic conditions, and is in the order of 10 to 12 times per kilometer. This results in the deterioration of the “contact”, which enables the functioning of the device. Hence the device requires premature replacement or frequent tuning, which are time consuming and results an increase in warranty costs and cost of service as well. Thus, to overcome this problem a unique and novel approach is proposed in this paper which enhances the life of the automobile horn, by implementing an additional pair of Contacts on circuit breakers, providing a parallel path for the power supply. This effort ensures that the life of the horn is increased by 5 times than the existing design. In addition, this approach completely eliminates the problems of premature failure or frequent tuning, yet without any change in the physical dimensions of the device, thus ensuring that no additional engineering efforts are required for its implementation.
Technical Paper
2014-04-01
Greg A. Sullenberger
Abstract A well-established methodology has often been used to calculate a speed-at-impact from the overall distance that a pedestrian is thrown as a result of a vehicle-pedestrian impact. (Searle, SAE #831622 and SAE #930659). The formulae were derived for use on typical road surfaces, such as asphalt, concrete, and grass. Significant testing has been done to validate the formulae on these normal surfaces. The current research was completed to assess if the same formulae are also applicable to lower-friction surfaces, e.g. snow, ice. Test dummies were impacted by automobiles or launched from a ramp in order to simulate the airborne trajectory of a vehicle-pedestrian collision. Speeds were measured with a radar unit and/or the analysis of high speed video. The overall distance traveled by the dummy from impact/launch to final rest was measured. A calculated friction value for the overall throw distance was based upon the known speed and distance and a known or approximated angle of takeoff.
Technical Paper
2014-04-01
Raed E. El-jawahri, Tony R. Laituri, Agnes S. Kim, Stephen W. Rouhana, Para V. Weerappuli
In the present study, transfer equations relating the responses of post-mortem human subjects (PMHS) to the mid-sized male Hybrid III test dummy (HIII50) under matched, or nearly-identical, loading conditions were developed via math modeling. Specifically, validated finite element (FE) models of the Ford Human Body Model (FHBM) and the HIII50 were used to generate sets of matched cases (i.e., 256 frontal impact cases involving different impact speeds, severities, and PMHS age). Regression analyses were subsequently performed on the resulting age-dependent FHBM- and HIII50-based responses. This approach was conducted for five different body regions: head, neck, chest, femur, and tibia. All of the resulting regression equations, correlation coefficients, and response ratios (PHMS relative to HIII50) were consistent with the limited available test-based results.
Technical Paper
2014-04-01
Toshiyuki Yanaoka, Yasuhiro Dokko
Abstract The high frequency of fatal head injuries of elderly people in traffic accidents is one of the important issues in Japan. One of the causes may be vulnerability of the aged brain. While a human head/brain FE model is a useful tool to investigate head injury mechanism, there has not been a research result using a model considering the structural and qualitative changes of the brain by aging. The objective of this study was to clarify the generational difference of intracranial responses related to traumatic brain injuries (TBI) under impact loading. In this study, the human head/brain FE models in their twenties (20s) and seventies (70s) were used. They were developed by reflecting the age-specific characteristics, such as shape/size and stiffness of brain matter and blood vessels, to the baseline model developed by Global Human Body Models Consortium (GHBMC) LLC. The generational difference of intracranial responses related to TBI, such as cumulative strain damage measure (CSDM), dilatational damage measure (DDM) and elongation of bridging vein (BV), were studied using the models.
Technical Paper
2014-04-01
William R. Bussone, Michael Prange
Abstract Few studies have investigated pediatric head injury mechanics with subjects below the age of 8 years. This paper presents non-injurious head accelerations during various activities for young children (2 to 7 years old). Eight males and five females aged 2-7 years old were equipped with a head sensor package and head kinematics were measured while performing a series of playground-type activities. The maximum peak resultant accelerations were 29.5 G and 2745 rad/s2. The range of peak accelerations was 2.7 G to 29.5 G. The range of peak angular velocities was 4.2 rad/s to 22.4 rad/s. The range of peak angular accelerations was 174 rad/s2 to 2745 rad/s2. Mean peak resultant values across all participants and activities were 13.8 G (range 2.4 G to 13.8 G), 12.8 rad/s (range 4.0 rad/s to 12.8 rad/s), and 1375 rad/s2 (range 105 rad/s2 to 1375 rad/s2) for linear acceleration, angular velocity, and angular acceleration, respectively. The peak accelerations measured in this study were similar to older children performing similar tasks.
Technical Paper
2014-04-01
Ellen L. Lee, Patrick J. Lee, Wilson C. Hayes
Abstract Non-neutral posture prior to impact is one of many factors thought to influence the onset and severity of whiplash associated disorders following low speed, rear impact collisions. The Graphical Articulated Total Body Model (GATB) is one simulation tool that has been used to investigate injury risk in rear impact collisions, though the model has not previously been validated for occupants in non-neutral postures. The main purpose of this study was to evaluate the performance of the GATB model during low speed rear impacts in out-of-position postures, by comparing simulations to previously published volunteer head accelerations. Twelve simulations (four occupants in each of three postures) were performed. Results demonstrated good agreement between the GATB simulations and the volunteer kinematics, with a mean error for peak head acceleration of 3.4 ± 13%. In addition, influence of out-of-position postures on the risk of whiplash injury for different sized occupants was investigated using the Neck Injury Criterion (NIC).
Technical Paper
2014-04-01
Chinmoy Pal, Tomosaburo Okabe, Kulothungan Vimalathithan, Muthukumar Muthanandam, Jeyabharath Manoharan, Satheesh Narayanan
Abstract A comprehensive analysis was performed to evaluate the effect of BMI on different body region injuries for side impact. The accident data for this study was taken from the National Automotive Sampling System-Crashworthiness Data System (NASS-CDS). It was found that the mean BMI values for driver and front passengers increases over the years in the US. To study the effect of BMI, the range was divided into three groups: Thin (BMI<21), Normal (BMI 24-27) and Obese (BMI>30). Other important variables considered for this study were model year (MY1995-99 for old vehicles & MY2000-08 for newer vehicles), impact location (side-front F, side-center P & side-distributed Y) and direction of force (8-10 o'clock for nearside & 2-4 o'clock for far-side). Accident cases involving older occupants above 60 years was omitted in order to minimize the bone strength depreciation effect. Results of the present study indicated that the Model Year has influence on lower extremity injuries. Occurrence of pelvis injury was found to be influenced by BMI and was validated with logistic regression analysis.
Technical Paper
2014-04-01
Jeff D. Colwell
Abstract Results from a full-scale vehicle burn test involving a 1998 compact passenger car were used to evaluate vehicle fire dynamics and how burn patterns produced during the fire correlated with important characteristics of the fire, such as the area of origin. After the fire was initiated at the air filter in the engine compartment, the fire spread locally and, once the temperature near the origin reached about 750°C, the temperature at all but one location within the engine compartment began to increase. These temperatures continued to increase for the next 6 minutes and then a temperature gradient began to develop in the passenger compartment between the ceiling and the floor. About 5 minutes after the engine compartment became fully involved, the ceiling temperature reached about 590°C and flame spread within the passenger compartment increased. Over the next 4 minutes, the passenger compartment also became fully involved. The fire then spread to the trunk and the rear wheels before self-extinguishing.
Technical Paper
2014-04-01
Guanyu Zheng, Indrek Wichman, Andre Benard, Hongyu Wang, Xiaohui Li, Jie Gao
Abstract Flame spread over a melting thermally thick composite polymer is investigated in a channel flow above a condensed fuel. The condensed fuel consists of an isotropic (melted layer of) liquid near the heated surface and an anisotropic (not-yet-melted) solid surrounding it. The influence of the solid anisotropy is evaluated by changing the solid conductivity (ksx or ksy) in one particular direction (x in horizontal flame spread direction or y in vertical direction, see schematics in Figure 1) while keeping the other properties fixed. Note that the liquid conductivity kl has no isotropic behavior. Numerically, it is found that the flame spread rate decreases with either increasing ksx or ksy. The decrease with respect to ksy is less than for a comparable case described by the de Ris formula for an isotropic pure solid. The flame spread rate is more accurately determined by an analytical formula derived for spread across a melting solid fuel. Qualitatively, the liquid layer extent decreases with either increasing ksx or ksy due to the role played by the solid conduction as a heat loss mechanism in a thermally thick fuel.
Technical Paper
2014-04-01
Raúl Ochoterena, Maria Hjohlman, Michael Försth
Abstract Fires in the engine compartments of surface and underground non-rail heavy duty vehicles are still highly frequent. Statistics show that most of the reported fires commenced in the engine compartment and that these were not promptly detected by the drivers. Fires which were not detected rapidly, spread oftentimes beyond the firewall of the engine compartment having notorious economical and environmental repercussions; furthermore, endangering the safety of the occupants. Detecting fires in the engine compartments of heavy duty (HD) vehicles with inexpensive and simple automatic detection systems is in general challenging. High air flows and large amounts of suspended pollutants, together with the complicated geometry and wide range of surface temperatures typically occurring during the normal operation of the vehicle, complicate the reliable operation of almost all types of detectors. This work presents a theoretical study assessing the effectiveness of different detection systems in a simulated fire scenario.
Technical Paper
2014-04-01
Pit Schwanitz, Sebastian Werner, Johannes Zerbe, Dietmar Göhlich
Abstract A new methodology for crash sensitive vehicle structures has been developed to be used during the early stage of the Product Development Process (PDP). By frontloading significant and simplified CAE simulations and the use of stochastic optimization methods in conjunction with highly parametric CAD models, new concepts can be quickly identified and evaluated based on reliable product insight. Vehicle crashboxes have been chosen for verification of the methodology. An analysis of different but comparable vehicles showed a large variety of designs although they all absorb the energy of low speed crashes within a velocity of up to 15km/h. A powerful optimization model with a parametric geometry engine, a crash-solver and suitable optimization software, used within a batch process, has been established. The optimal results for one particular crashbox concept are presented to demonstrate the methodology and the benefit of the approach. Due to the relocation of the variant calculation at early stage, the optimization potential can be used extensively.
Technical Paper
2014-04-01
Lothar Seybold, Bryan Styles, Ioannis Lazaridis, Hans-Joerg Kneusels
The European Commission (EC) as well as the United States Environmental Protection Agency (EPA) published legislations to regulate or encourage the use of low Global Warming Potential (GWP) refrigerants applied to Mobile Air Conditioning (MAC) systems. Europe mandates a GWP less than 150 of MAC refrigerants for new vehicle types. The thermodynamic refrigerant properties of R-1234yf are slightly different from the properties of R-134a, currently used in MAC systems. Although the basic material data show that R-1234yf is flammable, ignition tests performed for an automotive engine under-hood environment reveal design and packaging influences of its ignition behavior. After extensive collaborative research in 2009, the Society of Automotive Engineers Cooperative Research Team (SAE CRP1234) concluded that R-1234yf is suitable for use in automotive applications. Further ignition risk assessment regarding R-1234yf usage in MAC systems was done by SAE CRP1234-4 in 2013. They concluded that “risks are still very small compared to the risks of a vehicle fire from all causes and well below risks that are commonly viewed as acceptable by the general public.”
Technical Paper
2014-04-01
Mathias Poklitar, Lothar Seybold
As part of the launch of the refrigerant R-1234yf there were a number of studies done regarding the ignition behavior of this new refrigerant in passenger cars. These tests were conducted by a number of automobile manufacturers, component suppliers, and the refrigerant supplier under laboratory conditions at the component and vehicle level. In November 2009 the international automotive industry concluded that the R-1234yf can be used safely in automotive air conditioning systems. Further tests were conducted by different automobile manufacturers, suppliers, and the refrigerant supplier under various laboratory and vehicle operation conditions means hot surfaces in the engine compartment. A number of vehicle manufactures have conducted full vehicle crash tests. In this paper, real world accidents are analyzed using the German In-Depth Accident Study (GIDAS) database as well as the thermal parameters for ignition of R-1234yf, i.e. concentration and surface temperature to create a worst-case scenario.
Technical Paper
2014-04-01
John D. Bullough
Abstract Present standards for vehicle forward lighting specify two headlamp beam patterns: a low beam when driving in the presence of other nearby vehicles, and a high beam when there is not a concern for producing glare to other drivers. Adaptive lighting technologies such as curve lighting systems with steerable headlamps may be related to increments in safety according to the Insurance Institute for Highway Safety, but isolating the effects of lighting is difficult. Recent analyses suggest that visibility improvements from adaptive curve lighting systems might reduce nighttime crashes along curves by 2%-3%. More advanced systems such as adaptive high-beam systems that reduce high-beam headlamp intensity toward oncoming drivers are not presently allowed in the U.S. The purpose of the present study is to analyze visual performance benefits and quantify potential safety benefits from adaptive high-beam headlamp systems. Before adaptive high-beam systems could be permitted on U.S. roadways, it is necessary to have data describing their potential for crash reductions.
Technical Paper
2014-04-01
Mitsuhiro Uchida, Yasushi Kita, Takako Minoda(Kimura), Ryuji Ueki, Shoko Kawanobe
Abstract LEDs offer great advantages such as low power consumption and compact size. In addition to the physical benefits, however, they also boast 1.2times the feeling of brightness compared with halogen bulbs, as shown in previous research, and the colors of LED sources have been shown to stand out better than other sources (halogen and HID) used for traffic signs, offering superior perceived Clarity and sharpness. As well as traffic signs, it is essential to be able to see pavement markings clearly when driving an automobile. In this study, tests were carried out on public roadways using automobiles installed with halogen, HID and LED-based headlamps. It was found that the LED sources were found to provide the clearest illumination of the white lines. White lines on an actual road surface were also illuminated with halogen, HID and LED lamps in order to compare the effects of these sources on the visibility of the white lines by static evaluation. The results indicate that the LED sources provided a greater improvement in the visibility of the white lines than the other (halogen and HID) sources.
Technical Paper
2014-04-01
Anthony Dominic Cornetto, Jeffrey Suway, Ronny Wahba, Fawzi Bayan
Abstract Numerous studies have validated SIMON and DyMESH with respect to vehicle dynamics and crash analysis for accident reconstruction. The impetus for this paper is to develop an accessible methodology for calculating three-dimensional stiffness coefficients for HVE-SIMON and DyMESH. This method uses acceleration-time data (crash pulse) from a vehicle crash test, data that is widely available through the National Highway Traffic Safety Administration (NHTSA). The crash pulse, along with vehicle mass and impact speed, are used to calculate the force acting on the vehicle and the associated vehicle deflection time history. A technique for determining the area-deflection function is created from a computer model of the vehicle, HVE-SIMON, and basic photo-editing software. The calculated force divided by the associated area function (F/A) is plotted versus deflection and a third-order polynomial is then fit to the curve. The coefficients of this third-order polynomial are the A, B, C, and D stiffness coefficients.
Technical Paper
2014-04-01
Timothy P. Austin, Peter A. Chisholm, Roger W. Schreiber, P. Michael Neal
Abstract In the investigation of a collision involving recreational watercraft, analytical methods are generally limited when compared to incidents involving land-based vehicles. As is indicated in previous publications, investigators often rely on time/distance relationships, human factors, the matching of damage to determine vessel positioning at impact, and the recollections of witnesses. When applicable, speed estimates are generally based on the boat engine's revolutions. By considering the engine speed, the drive gear ratio, the propeller pitch, and the likely slip of the propeller, an estimation of the boat's travel speed can be made. In more recent publications, it has been recognized that Event Data Recorder (EDR) technology incorporated into various Electronic Control Units (ECUs) used in automotive applications can be beneficial to collision investigation and reconstruction. These devices record data surrounding diagnostic occurrences, airbag deployments, and, with respect to some heavy vehicles, “last stop” and/or “sudden deceleration” events.
Technical Paper
2014-04-01
Lisa P. Gwin, Herbert Guzman, Enrique Bonugli, William Scott, Mark Freund
Abstract There is a paucity of recent data quantifying the injury risk of forces and accelerations that act on the whole body in a back-to-front direction. The purpose of this study was to quantify the level of back-to-front accelerations that volunteers felt were tolerable and non-injurious. Instrumented volunteers were dropped supine onto a mattress, and their accelerations during the impact with the mattress were measured. Accelerometers were located on the head, upper thoracic and lower lumbar regions. Drop heights started at 0.6 m (2 ft) and progressed upward as high as 1.8 m (6 ft) based on the test subjects' consent. The test panel was comprised of male and female subjects whose ages ranged from 25 to 63 years of age and whose masses ranged from 62 to 130 kg (136 to 286 lb). Peak head, upper thoracic and lower lumbar accelerations of 25.9 g, 29.4 g and 39.6 g were measured. There was considerable restitution in the impacts with the mattress and the test subjects experienced changes in velocity (ΔVs) of 5.2-11.4 m/s (11.6-25.5 mph).
Viewing 181 to 210 of 15794

Filter

  • Article
    476
  • Book
    116
  • Collection
    42
  • Magazine
    615
  • Technical Paper
    10002
  • Subscription
    4
  • Standard
    4539