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2016-04-05
Technical Paper
2016-01-0397
Wenxin Qin, Sandip Datta, Weidong Zhang
In automotive chassis, body and powertrain finite element numerical analysis, more and more analysts and engineers like to adopt 3D complex FEA models along with improved computer hardware and software. The advantages of 3D FEA model are (1) looked like real model in vision; (2) simulation response is more vivid; (3) easily to discover the mistakes by watching simulation response. The drawbacks of 3D FEA model are (1) more pre/post process works and computation time; (2) numerical divergence is a challenging issue in nonlinear and contact situations and debug becomes difficulty; (3) sometimes accumulated numerical errors will cover the actual response. Therefore, it is necessary to explore what kinds of 3D FEA situations can be successfully converted by the simple 2D plan FEA models.
2016-04-05
Technical Paper
2016-01-0395
Anindya Deb, Clifford C. Chou, Gunti R. Srinivas, Sanketh Gowda, Goutham kurnool
An attractive strategy for joining non-ferrous or non-metallic substrates is through adhesive bonding. This technique of joining also offers the functionality for joining dissimilar materials. However, doubts are often expressed on the ability of such joints to perform on par with other mechanical fastening methodologies such as welding, riveting, etc. In the current study, adhesively-bonded single lap shear (SLS) and double lap shear (DLS) joints are studied initially under quasi-static (at a cross-head speed of 1 mm/min) tensile and flexural loading using steel and aluminum substrates, and an epoxy-based adhesive of a renowned make. The study includes usage of similar substrates made of only steel or aluminum, or a combination of steel and aluminum substrates. Load-displacements curves for bonded joints are presented for varying overlap lengths.
2016-04-05
Technical Paper
2016-01-1499
Willy Klier, Thomas Lich, Gian Antonio D’Addetta, Heiko Freienstein, Armin Koehler, Bastian Reckziegel, Zerong Yu
On the way to automated driving, the market penetration of surround sensing systems will rapidly increase in the upcoming years. The respective technical progress in the areas of driver assistance and active safety leads to a numerous and valuable information and signals to be used prior, during and even after an accident. Car makers and suppliers can make use of this new situation and develop new integrated safety functions to further reduce the number of injured and even deaths in car accidents. Nevertheless, the base occupant safety remains the core of this integrated safety system in order to ensure at least a state-of-the-art protection even in vehicles including partial, high or full automation. Current networked safety systems comprehend a point-to-point connection between single components of active and safety systems. The optimal integration requires a much deeper and holistic approach.
2016-04-05
Technical Paper
2016-01-1531
Dale E. Halloway
Occupant Kinematics in Distinct Types of Far-side Impacts Objective: Occupant contacts not on a trajectory not in line with a response to the resultant impact vector are seen as the consequence of post-impact vehicle rotation. This analysis evaluates field data for indications the trajectory occupant contacts indicate in far-side impacts is affected by the acceleration of the vehicle. Methods: Using the WinSMASH calculated moment arm a classification scheme was devised. WinSMASH calculates and reports moment arm length and sign. Moment arm length was used to classify impacts as ‘centric’ or ‘eccentric’ relative to the vehicle center of gravity. A query was made for far-side impacts in CIREN. 111 cases were reviewed and WinSMASH re-run. The results were used to classify impacts by the crush profile center-of-damage and principal direction of force. All AIS 2+ injuries were located on whole body and specific anatomic region mannequins.
2016-04-05
Technical Paper
2016-01-1505
William W. Van Arsdell, Paul Weber, Charles Stankewich, Brian Larson, Ryan Hoover, Richard Watson
This paper investigates the role that load limiters play with respect to the performance of occupant protection systems. Modern occupant protection systems consist of not just the seat belt, but also airbags, interior vehicle surfaces and vehicle structure. Modern seat belts very often incorporate load limiters as well as pretensioners. Published research has established that load limiters and pretensioners increase the effectiveness of occupant protection systems. Some individuals have argued that load limiters with higher deployment thresholds are always better than load limiters with lower deployment thresholds. Similarly, they have argued that load limiters should always include stops that limit the amount of webbing deployed due to load limiter actuation. Through testing and analysis, we have investigated this hypothesis and in this paper we present test data as well as a discussion to this data and engineering mechanics to explain why this hypothesis is incorrect.
2016-04-05
Technical Paper
2016-01-1470
Nathan A. Rose, Neal Carter, Gray Beauchamp
Calculating the speed of a yawing and braked vehicle often requires an estimate of the rate at which the vehicle decelerated over the course of its trajectory. During a steering induced yaw, the rotational velocity of the vehicle will typically be small enough that it will not make up a significant portion of the vehicle energy. However, when a yaw is impact induced and the resulting yaw velocity is high, the rotational component of the vehicle’s kinetic energy can be significant relative to the translational component. In such cases, the rotational velocity can have a meaningful effect on the rate at which the vehicle decelerates. In addition to the effects of rotational energy on the deceleration rate, high yaw velocities can also cause steering angles to develop at the front tires because the frictional forces between the tires and ground cause the yaw rotation of the tires to lag behind the yaw rotation of the vehicle.
2016-04-05
Technical Paper
2016-01-1462
Louis R. Peck, Mu-Hua Cheng
Three targeted vehicles of varying size were measured using an optimized, practical photogrammetry technique and the results were compared to measurements acquired via total station. The photogrammetry method included the use of a field-calibrated DSLR camera equipped with a fixed 20mm lens, retro-reflective targets sized for vehicular modeling, and a CNC-machined scale bar. Eight photographs were taken from proper angles and processed using a commercially available photogrammetry package, and that data was merged with the total station data using a cloud-to-cloud registration process for point-to-point comparison of positional data. The average residual between corresponding photogrammetry and total station points was 1.7 mm (N 258, SD = 0.8 mm) with a 95% confidence level of 3.3 mm. Considering this low residual, one of the sample vehicles was re-measured using a high accuracy FARO Arm for comparison to the photogrammetry technique.
2016-04-05
Technical Paper
2016-01-0403
Devendra M. Oza, Abhijit Londhe
Stiffness evaluation for the components made from natural rubber have been attempted here using Finite Element simulation technique. Conventional method for extraction of the stiffness with metallic parts like steel using linear approach is no more valid in rubber (elastomers). Unique properties of elastomers like sustaining strains up to 500% due to large deformation under loading (displacement unveils non-linear behavior with applied load), exhibiting significant damping property because of viscoelasticity and nearly incompressible in nature (no change in volume appreciably with stress) creates a need to seek for special material model and capture non-linear behavior. Stress vs strain behavior of elastomers under all possible loading conditions calls for physical sample test in uni-axial tension, uni-axial compression, bi-axial tension, planar shear and volumetric test. Two suspension rubber mounts and one engine mount have been analyzed with the current simulation technique.
2016-04-05
Technical Paper
2016-01-1480
Jakub Zebala, Wojciech Wach, Piotr Ciępka, Robert Janczur
This article presents the results of an analysis of the yaw marks left by a car with nominal pressure in all tires and with zero pressure in one rear tire. The analysis is a continuation of research on influence of reduced tire pressure on car lateral dynamics in a passing maneuver, discussed at the SAE Congress in 2014. Preliminary analysis of yaw marks has shown, that a wheel with zero pressure deposits a yaw mark whose geometry differs from the yaw mark made by a wheel with nominal pressure based on which we could calculate: critical speed, slip angle and longitudinal wheel slip. The aim of the presented research was to analyze the yaw marks left by car with zero pressure in one rear wheel in order to check the possibility of determining the vehicle critical speed, slip angle and longitudinal wheel. It was reached by performing bench and road tests during which the vehicle motion parameters were recorded using GPS Data Logging System.
2016-04-05
Technical Paper
2016-01-1461
William T. Neale, David Danaher, Sean McDonough, Tomas owens
Many of the smart phone devices widely available on the market today have built in functionality and equipment that may prove useful in certain procedures of accident reconstruction testing and analysis. Two technologies found on many of the devices include accelerometers and GPS tracking. Being capable of tracking the position, speed and acceleration of a vehicle being tested is obviously useful, but can a smart phone, enabled with this technology, provide veritable data for use in accident reconstruction? And what factors would affect the accuracy? This paper presents on this topic in three segments. First, the paper provides an overview of the accelerometer and GPS technology that is built in to smart phone devices. Second, this paper evaluates several versions of smart phones and related software that allows a user to track speed, position, acceleration, temperature, and elevation. The smart phones are tested in scenarios simulating walking, running, biking, and driving.
2016-04-05
Technical Paper
2016-01-1483
The objective of this study is to assess the accuracy of using high impact speed frontal barrier crash tests to predict the deformation energy for a lower impact speed frontal barrier crash. To make this prediction, two key assumptions were made: the frontal barrier crash tests are repeatable for the same model vehicle, and the rebound phase in the force vs deflection curve is similar for the same vehicle model regardless of impact speed. For each vehicle to barrier test, the vehicle’s force vs. deflection curve will be created by synchronizing the barrier’s load cell data with a double integration of the vehicle’s accelerometer data. The deformation energy dissipated during each barrier impact will be calculated by integrating the corresponding force vs. deflection curve. To verify that all deformation energy was accounted for in the test data, the deformation energy will be used to calculate the test EBS.
2016-04-05
Technical Paper
2016-01-1503
Typical seatbelts have a locking mechanism referred to as an emergency locking retractor. This locking mechanism operates in response to an acceleration or deceleration input or to the sudden extension of the seatbelt. However, because the clothing of vehicle occupants can produce slack in the seatbelt, it is possible that a vehicle occupant may move forward before being restrained by the seatbelt. In these types of situations, if the vehicle occupants do not maintain their posture through their own strength muscles, by inertia of the vehicle, the posture of the vehicle occupants may change due to the slack caused by the way in which the seatbelts are used. To suppress the forward movement of the occupant, the motorized seat belt had been developed. Motorized seatbelt systems that retract seatbelts using motors are being mass-produced by many manufacturers.
2016-04-05
Technical Paper
2016-01-1351
Simhachalam Bade
Aluminum alloys are widely used in the transportation because of their high strength-to-weight ratio and outstanding capability in absorbing energy. In this paper, performance of bumper with crash tubes using aluminum alloy AA6061 and AA7003 materials is compared using numerical methods. Quasi-static test is simulated using the LS-DYNA implicit finite element program. Bumper and crash tubes are included in the finite element model. Symmetric Holes are provided in the crash tubes to initiate crushing. True stress-plastic strain curves from the tensile test are used in the static simulation. Displacement is applied to the bumper using Rigdwall geometric wall motion. The energy absorbed by bumper and crash tubes are compared. Dynamic simulation is done using LS-Dyna explicit program. True stress-true plastic strain curves at different strain rates from the literature is used in the dynamic simulation of AA7003 material to study the strain rate effects on impact behavior of tubes.
2016-04-05
Technical Paper
2016-01-1530
Yury Chudnovsky, Justin Stocks-Smith, Jeya Padmanaban, Joe Marsh
A comprehensive review of technical literature addressing injury risk in near- and far-side impacts was performed, and NASS/CDS data (1998-2013) was examined to address serious injury rates, sources, and nature for belted drivers in side impacts. Frequency and severity of near- and far-side impacts by crash severity (delta-V) were compared for older (1994 – 2007 MY) and newer vehicles (2008+ MY). For 2008 MY, individual cases were examined for serious injury factors in far-side impacts. Near- and far-side impacts were identified using principal direction of force and general area of damage. Results show that about 90% of NASS/CDS side impacts have a delta-V under 15 mph for both older and newer cars. The serious injury rate for belted drivers in older cars is 5.5% for near-side crashes and 1.2% for far-side crashes. For newer models, the serious injury rate for belted drivers is 2.5% near-side and 0.5% far-side.
2016-04-05
Technical Paper
2016-01-1524
Feng Zhu, Binhui Jiang, Clifford C. Chou
This paper represents the development of a new design methodology based on data mining theory for decision making in vehicle crashworthy products development. The new methodology allows exploring the big crash simulation dataset to discover the underlying complicated relationships between vehicle crash responses and design variables at multi-levels, and deriving design rules based on the whole vehicle safety requirements to make decisions towards the component and sub-component level design. The method to be developed will resolve the issue of existing design approaches for vehicle crashworthiness, i.e. limited information exploring capability from big datasets, which may hamper the decision making and lead to a poor design. A preliminary design case study is presented to demonstrate the performance of the new method. This method will have direct impacts on improving vehicle safety design and can readily be applied to other complex systems.
2016-04-05
Technical Paper
2016-01-1498
Hironori Wakana, Masuyoshi Yamada, Minoru Sakairi
The problem of high fatal accident rates due to drunk driving persists, and it must be solved. In Japan, to reduce the number of accidents caused by drunk driving, the drivers of buses and trucks have been required to carry out an alcohol check before taking the wheel since 2011. We have been studying an alcohol detection system in breath for safe driving since 2008. This paper reports on a portable device that enables checking the sobriety of drivers using a breath-alcohol-detection system. The system consists of a water vapor sensor and three semiconductor gas sensors, for ethanol, acetaldehyde, and hydrogen. One of this system’s features is that the system detects water vapor from human exhaled breath to prevent false detection by fake gases. Each gas concentration is calculated by applying an algorithm based on a differential evolution method. To quickly detect the exhaled breath, we applied AC voltage between the two electrodes of the water sensor.
2016-04-05
Technical Paper
2016-01-1532
Kyoungtaek Kwak, Seungwoo SEO, Randi Potekin, Antoine Blanchard, Alexander Vakakis, Donald McFarland, Lawrence Bergman
In order to secure the safety of the passengers, the door should be kept closed during side impact crash and many car makers conduct a various research on this area. Typically, there are two major factors that affect the opening of door during side impact crash tests. One is a physical failure such as the damage of linkage of door locking system, which can be intuitively analyzed and resolved. The other is the inertia effect due to the instantaneous impact and deformation between a barrier and door outer panel. In case that the door opening is, however, resulted from the inertia effect, it is difficult to be intuitively resolved because it takes extremely short time less than 30ms for a whole phenomenon to come out. Also, because the randomly deformed outer panel due to the crash generates not only translational but also angular accelerations that more complicatedly affect dynamic behavior of door handle.
2016-04-05
Technical Paper
2016-01-1477
The ability to accurately calculate a snowmobile’s speed based on measured track marks in the snow is important when assessing a snowmobile accident. The characteristics and length of visible snowmobile track marks were documented for 41 locked-track braking tests and 38 rolldown tests using four modern snowmobiles on a groomed/packed snow surface. The documented track mark lengths were used to quantify the uncertainty associated with using track mark length to estimate initial speed. Regression models were developed for both data sets. The regression model of the locked-track tests revealed that using an average deceleration of 0.36g over the length of the locked track mark provides a good estimate of the best-fit line through the data, with the upper and lower 95th percentile prediction interval bounds best represented by using deceleration rates of 0.23g and 0.52g respectively.
2016-04-05
Technical Paper
2016-01-1501
Aditya Belwadi, Richard Hanna
Automotive interior design optimization must balance the design of the vehicle seat and occupant space for safety, comfort and aesthetics with the accommodation of add-on restraint products such as child restraint systems (CRS). It is important to understand the range of CRS dimensions so that this balance can be successfully negotiated. CRS design is constantly changing. In particular, the introduction of side impact protection for CRS as well as emphasis on ease of CRS installation has likely changed key design points of many child restraints. This ever-changing target creates a challenge for vehicle manufacturers to assure their vehicle seats and occupant spaces are compatible with the range of CRS on the market. To date, there is no accepted method for quantifying the geometry of child seats such that new designs can be catalogued in a simple, straightforward way.
2016-04-05
Technical Paper
2016-01-1500
Renran Tian, Keyu Ruan, Lingxi Li, Jerry Le, Mike Rao
Driver state sensing technologies start to be widely used in vehicular systems developed from different manufacturers. To optimize the cost and minimize the intrusiveness towards driving, majority of these systems rely on the in-cabin camera(s) and other optical sensors. With their great capabilities of detecting and intervening driver distraction and inattention, these technologies might become key components in future vehicle safety and control systems. However, currently there is no common standard available to compare the performance of these technologies, thus it is necessary to develop one standardized process for the evaluation purpose.
2016-04-05
Technical Paper
2016-01-1523
Libo Cao, Changhai Yao, Hequan Wu
The traditional deterministic optimal design mostly is based on meeting regulatory requirements specified in impact standards ,without taking the randomness of the impact velocity and impact angle at the real world situation into consideration. This often leads to the optimization results that converge to the boundary constraints, thus cannot meet the reliability requirements of the product design. This paper deals with optimization of B-pillar inner panel, outer panel, and the reinforcing plate which plays a major role in the safety performance in side impact crashes by considering their dimensions and materials as the design variables, and the impact velocity and impact angle from real-world traffic accident conditions as the random variable inputs . Using combined design of experiment, response surface models, reliability theory and the reliability of design optimization method, a B-pillar was constructed based on the product quality engineering.
2016-04-05
Technical Paper
2016-01-0398
Yuqing Zheng, Xichan Zhu, Xueqing Dong
Customer demand and safety regulatory requirements continue to drive automakers to develop vehicles with better fuel efficiency and structural performance. To overcome some drawbacks of using AHSS (Advanced High Strength Steel) in hard machining and part welding for vehicle weight reduction, such as brittleness, spot weld HAZ (Heat Affected Zone) softening and high cost. The strength distribution and energy absorption behavior of thin-walled box structures with higher strength in ridgelines under bending and axial compressive load were firstly studied in this paper by describing different collapse modes in the ridgeline and flat plate. And the corresponding energy absorption evaluations are theoretically derived. Furthermore, the CAE simulation models for above structures are developed to demonstrate the theoretical conclusions.
2016-04-05
Technical Paper
2016-01-1472
Dietmar Otte, Martin Urban lng, Heiko Johannsen PhD
This paper shows a new method for generating pre-crash scenarios directly from the reconstruction of the accident by using the software PC-Crash . The new method has been developed by the Medical University Hannover and the Fraunhofer Institute for Transportation Dresden based on transferring all information (participant-, vehicle-, environment- and motion-data) from the reconstruction file of in-depth-data into a scenario-database. In order to analyse boundary conditions (e.g. introduction of certain active safety systems), a so-called Pre Crash Matrix (PCM) of time related parameter of the pre crash phase was developed by the Dresden Accident Research Team (VUFO) in 2008 . By using the PCM and including 5 seconds before the crash, the driving behaviours of the vehicles is digitalized out of PC-Crash data and the scenarios are analysed, whether or not a sensor system would have been able to recognise the dangerous situation in time to avoid or mitigate the accident.
2016-04-05
Technical Paper
2016-01-1484
Terry D. Day
This paper presents the application of simulation software to reconstruct the famous car chase scene from the 1968 movie “Bullit.” In this car chase, a 1968 Ford Mustang, driven by Lt. Frank Bullit of the San Francisco Police Department, is chasing a criminal driving a 1968 Dodge Charger through the hilly streets of the Russian Hill district of San Francisco. The purpose of the simulation was to reconstruct the chase scene to determine the level of realism. To produce the simulation, several city blocks of the pertinent area of the city were surveyed and exemplar vehicles were measured and inspected. 3-dimensional computer models of the scene and vehicles were built. The movie footage was analyzed to determine driver inputs and vehicle speeds. The event was then simulated using 3-dimensional simulation software. The results of the simulation confirmed the vehicles could not have navigated through the course at the speeds shown in the movie.
2016-04-05
Technical Paper
2016-01-1528
Peijun Ji, Qing Zhou
For crash protection, it is desirable that the restraint loads are spread to the sturdy parts of human body such as head, shoulders, rib cage, pelvis and femurs, as uniformly as possible. However, seatbelts and airbags may have some deficiency in this regard even though they have been proved to be effective restraint devices for occupant impact protection. Seatbelt could generate unwanted local penetrations to the chest and abdomen and airbag could pose disproportional risks to small stature and out-of-position occupants. The problem is more prominent in severe crash. Some study has also shown that restraint in the vehicles on the market today could not efficiently protect occupants in high-speed crash, however they are optimized. This paper explores a uniform restraint concept aiming at providing protection at higher impact velocity. In this study, we use THUMS 50th percentile occupant model to simulate sled test frontal impact loading.
2016-04-05
Technical Paper
2016-01-1517
Cole R. Young PE, David J. King, James V. Bertoch
The purpose of this study was to characterize the kinematics of four Chevrolet Tracker rollover tests and to determine their average and intermediate deceleration rates while traveling on concrete and dirt. Single vehicle rollover tests were performed using four 2001 Chevrolet Trackers fitted with six degree of freedom kinematic sensors. Tests were conducted using a rollover test device (RTD) in accordance with SAE J2114. The test dolly was modified (resting height of the vehicle wheels was raised) between tests 1, 2, and 3. The RTD was accelerated to 15.6 m/s (35 mph) and then decelerated rapidly by an energy absorbing crash cushion (EA) to cause the vehicle to launch and roll. The vehicles initially rolled on a smooth concrete surface and continued into loose dirt. This paper adds to the body of work identifying phases of constant deceleration during staged RTD tests and compares these phases to the overall deceleration rate.
2016-04-05
Technical Paper
2016-01-1467
Improvements in computer image processing and identification capability have led to programs that can rapidly perform calculations and model the three-dimensional spatial characteristics of objects simply from photographs or video frames. This process, known as structure-from-motion or image based scanning, is a photogrammetric technique that analyzes features of photographs or video frames from multiple angles to create dense surface models or point clouds. Concurrently, unmanned aircraft systems have gained widespread popularity due to their reliability, low-cost, and relative ease of use. These aircraft systems allow for the capture of video or still photographic footage of subjects from unique perspectives. This paper explores the efficacy of using a point cloud created from unmanned aerial vehicle video footage with traditional single-image photogrammetry methods to recreate physical evidence at a crash scene.
2016-04-05
Technical Paper
2016-01-1529
Gunti R. Srinivas, Anindya Deb, Clifford C. Chou, Malhar Kumar
Periprosthetic fractures refer to the fractures that occur in the vicinity of the implants of joint replacement arthroplasty. Most of the fractures during an automotive frontal collision involve the long bones of the lower limbs (femur and tibia). Since the prevalence of persons living with lower limb joint prostheses is increasing, periprosthetic fractures that occur during vehicular accidents are likely to become a considerable burden on health care systems. It is estimated that approximately 4.0 million adults in the U.S. currently live with a Total Knee Replacement (TKR). Therefore, it is essential to provide countermeasures in the automotive design that minimize the severity of the periprosthetic fractures. The aim of the present study is to develop an advanced finite element model that simulates the possible fracture patterns that are likely during vehicular accidents involving occupants who have joint prostheses in situ.
2016-04-05
Technical Paper
2016-01-0396
Prasad S. Mehta, Jennifer Solis Ocampo, Andres Tovar, Prathamesh Chaudhari
Biologically inspired designs have become evident and proved to be innovative and efficacious throughout the history. This paper introduces a bio-inspired design of a vehicle structure that is lightweight and provides outstanding crashworthiness indicators, e.g., high specific energy absorption and reduced peak crushing force. In the proposed approach, the protective function of the vehicle structure is matched to the protective capabilities of natural structures such as the fruit peel (e.g., pomelo), abdominal armors (e.g., mantis shrimp), bones (e.g., ribcage and woodpecker skull), as well as other natural protective structures with analogous protective functions include skin and cartilage as well as hooves, antlers, and horns, which are tough, resilient, lightweight, and functionally adapted to withstand repetitive high-energy impact loads.
2016-04-05
Technical Paper
2016-01-1538
Vaibhav V. Gokhale, Carl Marko, Tanjimul Alam, Prathamesh Chaudhari, Andres Tovar
This work introduces a new Advanced Layered Composite (ALC) design that redirects impact load through the action of a lattice of 3D printed micro-compliant mechanisms. The proposed ALC is composed of three layered phases: (1) outer hard shell, (2) compliant buffer zone, and (3) inner soft core. The outer shell is a layered composite of woven fiber imbibed into high-impact polymer matrix. The compliant buffer zone is made of 3D printed thermoplastic material. The inner core is made of impact arresting material (crushable foam). The compliant buffer zone, comprised by the lattice of micro-compliant mechanism, is designed using topology optimization to dynamically respond by distributing localized impact in the normal direction into a distributed load in the radial direction (perpendicular to the normal direction). The compliant buffer zone depicts large radial deformation in the middle but not on the surface, which only move in the normal direction.
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