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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
2015-01-1485
Jiri Kral, Theresa Kondel, Mark Morra, Stephen Cassatta, Peter Bidolli, Patrick Stebbins, Vikas Joshi
A new apparatus for testing modern safety belt systems was developed. Its design, dynamic behavior and test procedure are described. A number of tests have been conducted using this apparatus. These tests allowed identification of key performance parameters of pretensioners and load limiting retractors which are relevant to occupant protection in crash environment. Good test repeatability was observed, which allows comparison of different safety belt designs. The apparatus may be used for better specification and verification of safety belt properties on subsystem level as well as for validation of CAE models of safety belts used in simulations of occupant response to crash.
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
2015-01-1492
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
2015-01-1480
Seung Kwon Cha, Jong Heon Lee, Un Ko, Tae Hoon Song, HangChul Ko, YangGi Lee
This paper focuses on the Barrier net system of the European vehicle(wagon). Recently, Car maker has being developed the wagon for European market. The characteristic of this vehicle is to have a capability of enough luggage space in order to minimize injuries of passengers at the accident. This is also a requirement of EU regulations(ECE R-17). Our company has adopted this system to small size car for the first time dependent on advanced foreign company’s technology. This reality still gives us the burden of high cost and royalty expenditure. Therefore, the objective of this study is to overcome our weak technologies, especially for patent circumvention or new mechanism which is entirely independent with previous system, and cost effectiveness(Barrier Net).
2015-04-14
Technical Paper
2015-01-1443
Morteza Seidi, Marzieh Hajiaghamemar, James Ferguson, Vincent Caccese
Falls in the elderly population is an important concern to individuals, family, friends, and in the healthcare industry. When the head is left unprotected, head impact levels can reach upwards of 500 g (gravitational acceleration), which is a level that can cause serious injury or death. A protective system for a fall injury needs to be designed with specific criteria in mind including energy protection level, thickness, stiffness, weight, and cost among others. The current study quantifies the performance of a protective head gear design for persons prone to falls. The main objective of this paper is to evaluate the injury mitigation of head protection gear made from a patented system of polyurethane honeycomb and dilatant materials. To that end, a twin wire fall system equipped with a drop arm that includes a Hybrid-III head/neck assembly was used.
2015-04-14
Technical Paper
2015-01-1476
P Selvakumar, Arun Mahajan, R Murasolimaran, C Elango
Roll-over protective structures (ROPS) are safety devices which provide a safe environment for the tractor operator during an accidental rollover. The ROPS must pass either a dynamic or static testing sequence or both in accordance with SAE J2194. These tests examine the performance of ROPS to withstand a sequence of loadings and to see if the clearance zone around the operator station remains intact in the event of an overturn. In order to reduce costs and shorten product development cycle, non-linear finite element (FE) analysis is practiced routinely in ROPS design and development. Often correlating the simulation with the results obtained from testing a prototype validates the CAE model and its assumptions. This research has the proposal of showing the correlation between simulation and prototype test results of tractor ROPS. The FE analysis follows SAE procedure J2194 for testing the performance of ROPS.
2015-04-14
Technical Paper
2015-01-1472
Roberto Arienti, Carlo Cantoni, Massimiliano Gobbi, Giampiero Mastinu, Mario Pennati, Giorgio Previati
The lightweight seat of a high performance car is designed taking into account a rear impact. The basic parameters of the seat structure are derived resorting to the simulation of a crash test. A dummy is positioned on the seat and subject to a rear impulse. The simulations provide the dynamic loads acting on the seat structure, in particular the ones applied at the joint between the seat cushion and the seat backrest. Such a joint is simulated as a plastic hinge and dissipates some of the crash energy. By means of the simulations the proper parameters of the plastic hinge can be derived to design a safe seat. The simulations are validated by means of indoor tests with satisfactory results. By using the validated model, the influence of seat cushion and backrest parameters on seat passenger's injury are studied. An efficient tool has been developed for the preliminary design of lightweight seats for high performance cars.
2015-04-14
Technical Paper
2015-01-1484
Daniel E. Toomey, Eric S. Winkel, Ram Krishnaswami
The evolution of airbag sensing system design has been rapid as electromechanical sensors used in earlier front airbag applications have been replaced by multi-point electronic sensors used to discriminate collision mechanics for potential airbag deployment in front, side and rollover accidents. In addition to multi-point electronic sensors, advanced airbag systems incorporate a variety of state sensors such as seat belt use status, seat track location, and occupant size classification that are taken into consideration by airbag system algorithms and occupant protection deployment strategies. Historically, traditional reconstruction methods and full scale vehicle crash testing were the primary means available to evaluate the field performance of passenger vehicle airbag systems. Electronic sensing systems have allowed for the advent of electronic data recorders (EDRs), which over the past decade, have provided increasingly more information related to airbag deployment events.
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
2015-01-1430
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
2015-01-1330
Yoshiyuki Tosa, Hiroyuki Mae
The passenger airbag hits the windshield when it deploys, causing the impulse force to the windshield. To protect passengers, we must adequately support the airbag between the windshield and the instrument panel. We must not fracture the windshield deploying the airbag. We reviewed methods to simulate the stress on the windshield during deployment. This research predicts the dynamic strain on the windshield from deploying the airbag without vehicle tests. Deployment is fast enough to ignore spatial difference in the patterns of the pressure time histories. In this study, the prediction method consists of a deployment test and an FE simulation. The simple deployment test measures the dynamic pressure distribution between the airbag and the flat panel simulating the windshield.
2015-04-14
Technical Paper
2015-01-1341
Hisaki Sugaya, Yoshiyuki Tosa, Kazuo Imura, Hiroyuki Mae
When airbags deploy they break a plastic tear part of the instrument panel. Timing and the tear fracture process change the airbag’s deployment behavior. The tear fracture process is dependent on the plastic’s temperature. We developed a tear fracture simulation . Because the tear line is composed of 1mm width and 0.5mm-3.0mm flute thickness, simulating the tear fracture process is difficult, even using two models: airbag deployment, and plastic fracture. Thickness determines the tear fracture. The strain distribution of its parts should be predicted accurately. The tear fracture using solid mesh, which is 0.1mm mesh pitch, is predictable. Although it is a very complicated model and has a high computation cost, it is not applicable to the mass production development. We increase the accuracy of the tear fracture process prediction using the shell mesh, which is applicable to the mass production development.
2015-04-14
Technical Paper
2015-01-1409
Joseph Yoon, Kajetan Kietlinski, Freerk Bosma, Martin Tijssens
These days, we begin to see more vehicles equipped with new active safety systems such as radar/camera system and collision imminent braking (CIB) system, etc. The active safety systems are designed and introduced as a safety system in order to help avoid crashes or mitigate injuries when crashes are unavoidable. However, through some internal study conducted at TASS International, we discovered that there may be a potential risk of increased injuries to the occupant when the activation of the active safety systems is not coordinated with that of the passive safety system. For example, when CIB is activated, it puts the occupant out of position closer to the deploying airbag therefore potentially increase injury risks. This risk is believed to be more severe if the occupant is not belted.
2015-04-14
Technical Paper
2015-01-1451
Anand Sai Gudlur, Theresa Atkinson
ABSTRACT The current study examined field data in order to document injury rates, injured body regions, and injury sources for persons seated in the second row of passenger vehicles. It was also intended to identify whether these varied with respect to age and restraint use in vehicles manufactured in recent years.Data from the 2007-2012 National Automotive Sampling System (NASS/CDS) was used to describe occupants seated in the second row of vehicles in frontal crashes. Injury plots, comparison of means and logistic regression analysis were used to identify factors associated with increased risk of injury. Restraint use reduced the risk of AIS ≥ 2 injury from approximately 1.8% to 5.8% overall. Seventy nine percent of the occupants in the weighted data set used either a lap and shoulder belt or child restraint system. The most frequently indicated injury source for persons with a MAIS ≥ 2 was “seat, back support”, across restraint conditions and for all but the youngest occupants.
2015-04-14
Technical Paper
2015-01-1460
Massoud Tavakoli, Janet Brelin-Fornari
This study was conducted to explore the effect of various combinations of seatbelt-related safety components on the adult rear passenger involved in a frontal collision. The study was conducted on a 50th male and a 5th female Hybrid III ATD in the rear seat of a mid-sized sedan. Each ATD was seated in an outboard position with 3-point continuous lap-shoulder belts. On these belts were combinations of pretensioners and load limiters. Since the main objective of the test series was to cross-compare the seatbelt configurations, front seats were not included in the buck to avoid the possibility of contact with the front seat, hence avoiding such uncontrollable variables. Nevertheless, there was a short barrier devised to act as a foot-stop for both ATDs. A design of experiment (DOE) was constructed as a full factorial with and without a pretensioner and three types of load limiters. Each ATD was tested with a progressive load limiter (PLL1).
2015-04-14
Technical Paper
2015-01-1456
Mani Ayyakannu, Latha Subbiah, Mohammed Syed
Abstract: Knee Bolster requirements have changed substantially in recent years due to expanded safety requirements. A knee bolster assembly has been evolved to meet this matrix of requirements while being extremely lightweight (as low as 2 lbs), low in cost and easily tunable to work in various car/truck programs. The energy absorber is the primary component of this assembly and allows for a range of occupant sizes and weights to be protected( from a 50 Kg/5ft 5th percentile female to a 100 Kg/6ft 2 in 95th percentile male occupants). The evolution of this knee bolster assembly design is described using crush analysis, component testing to validate the crush analysis, instrument panel assembly level analysis with occupant models and sled tests. Steel and aluminum versions of this knee bolster are compared - in terms of weight, cost, design tunability for various crash conditions, structural stiffness etc.
2015-04-14
Technical Paper
2015-01-1459
Lotta Jakobsson, Magnus Björklund, Anders Axelson
Vertical accelerations can cause thoracic and lumbar spine injuries to a car occupant. Representative crashes potentially causing occupant vertical accelerations include; rollover events or free flying events when the car lands on its wheels, and run off road events when the car goes into the ditch and collides with an embankment from a crossing road. The spinal tolerances are dependent on occupant posture at time of impact which is an important factor with respect to limit of tolerances. Up to date, there is no standardized test method evaluating this occupant loading mechanism. The aim of this study was to develop test methods addressing vertical acceleration for car occupants and to evaluate countermeasures reducing the vertical loadings. Based on real world run off road crash investigations, representative test track methods were developed; including free flight before landing on the wheels and traveling in ditch impacting an embankment.
2015-04-14
Technical Paper
2015-01-1453
Jingwen Hu, Kurt Fischer, Paul Lange, Angelo Adler
Recent field data analyses have shown that front seats may provide better occupant protection than rear seats in newer vehicle models. The design of vehicle rear-seat compartment for protecting occupants is more challenging than front-seat because of the wide range of occupant ages and sizes that must be accommodated and protected. Furthermore, the increased demand for vehicle fuel economy will result in smaller rear-seat compartment and higher crash pulses, both of which will need further efforts to better protect rear-seat occupants. Therefore, the objective of this study is to use sled tests to quantify the effects of crash pulse, impact angle, occupant size, and front seat location on rear seat occupant protection. In this study, a sled buck representing a current compact vehicle was developed based on a HYGE system.
2015-04-14
Technical Paper
2015-01-1457
Aditya Belwadi, Richard Hanna, Audrey Eagle, Daniel Martinez, Julie Kleinert, Eric Dahle
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 breadth of CRS dimensions so that this balance can be successfully negotiated. Previously this was addressed with the advent of advanced air bag systems, when emphasis was placed on the design and development of surrogate child restraints, which were used, in developing and testing occupant sensing and classification systems. 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 any child restraints. This ever-changing target puts pressure on the vehicle manufacturers to keep their vehicle seats and occupant space compatible.
2015-04-14
Technical Paper
2015-01-1455
Kenshi Torikai, Hitoshi Higuchi, Kazuhiro Seki
Airbags help mitigate direct hits. The passenger airbag has a vent structure discharging the internal gas such that a suitable airbag reaction force is obtained. Since the conventional vent structure is always open, the reaction force of such an airbag tends to fall when the contact timing (CT) is long. What prevents this drop in the airbag reaction force is a structure which closes the vent hole until contact to maintain the internal pressure and opens the vent hole after contact. However, variable vent structures are typically complicated and difficult to control due to the lid of the vent hole and a strap to pull the lid. We researched a simplified variable vent structure, investigating a “slit type” vent structure to reduce the complexity of conventional variable vent structures.
2015-04-14
Journal Article
2015-01-1433
R. Matthew Brach, Raymond M. Brach, Richard A. Mink
This paper presents a novel reconstruction technique in which nonlinear optimization is used in combination with an impact model to quickly and efficiently find a solution to a given set of conditions to reconstruct a collision. These conditions correspond to known or prescribed collision information (physical evidence) and can be incorporated into the optimized collision reconstruction technique in a variety of means including as a prescribed value, through the use of a constraint, as part of a quality function, or possibly as a combination of these means. This reconstruction technique provides a proper, effective, and efficient means to incorporate data collected by event data recorders (EDR) or engine control modules (ECM). The technique is presented using the Planar Impact Mechanics (PIM) collision model in combination with the Solver utility in Microsoft Excel.
2015-04-14
Technical Paper
2015-01-1452
Kathleen DeSantis Klinich, Kyle Boyle, Laura Malik, Miriam Manary, Jingwen Hu
This study documented the position and orientation of child restraint systems (CRS) installed in the second rows of vehicles, providing a database of 486 installations. Thirty-one different CRS were evaluated, selected to provide a range of manufacturers, sizes, types, and weight limits. Eleven CRS were rear-facing only, fourteen were convertibles, five were combination restraints, and one was a booster. Ten top-selling vehicles were selected to provide a range of manufacturers and body styles: four sedans, four SUVS, one minivan, and one wagon. Each CRS was marked with three reference points on each moving component. The contours and landmarks of each CRS were first measured in the laboratory. Vehicle interior contours, belt anchors, and LATCH anchors were measured using a similar process. Then each CRS was installed in a vehicle using LATCH according to manufacturers’ directions, and the reference points of each CRS component were measured to document the installed orientation.
2015-04-14
Technical Paper
2015-01-1473
Kalu Uduma, Dipu Purushothaman, Darshan Subhash Pawargi, Sukhbir Bilkhu, Brian Beaudet
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.
2015-03-10
Technical Paper
2015-01-0024
Jaehaeng Yoo
Abstract For the robust passenger NCAP(New Car Assessment Program) 5star and the stable neck injury performance, a new concept of passenger airbag has been required. Especially, the deployment stability and the vent hole control technology of the passenger airbag can be improved. According to these requirements, the deployment stability technique has been studied and the ‘Active Vent’ technology has been developed. As a result, these technologies have led to achieve the robust NCAP rating and are applied to the production vehicles.
2015-03-10
Technical Paper
2015-01-0026
Wenku Shi, Changxin Wang, Zan Li
Abstract In order to improve the handling and stability of a light bus at high speed, a virtual model was established in Adams-Car and its anti-roll bar and bushing parameters were virtually optimized. The tyre mechanical characteristics were firstly tested by using a plate-type tyre tester and the Magic Formula parameters of the tyre were obtained. Then the virtual bus model's handling performance were studied by the simulation of central steering test and steady static circular test. An optimal matching method was put forward. By using genetic algorithm to conduct optimization, the optimised parameters were obtained. After that the anti-roll bar and bushing samples were respectively manufactured. At last, the comparative trials were performed in an automotive proving ground, and the subjective evaluation of the light bus's handling and stability was taken by three specialized assessors.
2015-03-10
Technical Paper
2015-01-0064
Sung Hoon Cho
Abstract The rollcage for WRC race body/rollcage has been developed and optimized by DFSS methodology. It is designed on the principle of reducing it to a Min. of weight compared to the other OEM and the initial set-up model with the torsional stiffness and strength increased. As a result, 12% increased torsional stiffness, maximized strength and 3.7% weight reduction could be achieved. In terms of economics, it is feasible to have a production cost savings of about 11% per car and the effect is further, considering the development period is substantially decreased, 5 to 2 months. Also, in the process of optimizing rollcage structure, applicable items to monocoque body are suggested by investigating the parts and structures that highly affect the body performance.
2015-03-10
Technical Paper
2015-01-0049
Shane Richardson
Abstract Within the exploration and resources sector some companies have required the fitment of Roll Over Protective Structures (ROPS). The issues with respect to: no ROPS, internal ROPS or external ROPS are discussed. The practical experience of designing, testing, fitting external ROPS in southern Africa are detailed as well as the investigation and analysis of a number of rollover crashes of vehicles fitted with the external ROPS and injury outcomes are compared with USA rollover injury data.
2015-02-02
WIP Standard
J397
This SAE Standard applies to operator protective structures which may commonly be a part of construction, forestry, mining, and industrial machines. To establish limits on deflection permissible during laboratory evaluations of certain operator protective structures, such as ROPS, FOPS, OPS, and FOG as defined in other SAE standards.
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