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Technical Paper

A High Performance Passive Muffler Valve

2009-05-19
2009-01-2039
A new passive muffler valve has been developed that offers the advantages of both the current passive and active valves without their major drawbacks. Like current passive valves this new valve provides high restriction at low to medium engine speeds for improved noise control. But with a near over-center spring action and unique flap shape, this high performance valve has minimal pressure drop at high engine speeds, closer to the active valve pressure drop performance. The in-line design of the valve makes it ideal for low restriction OE mufflers, resonators, and aftermarket performance mufflers. The new valve design is uncomplicated, with few components and has been tested extensively for durability utilizing both bench and vehicle level testing.
Technical Paper

Design of the Occupant Protection System for Critical Side Impact requirements

2009-12-13
2009-28-0055
This paper describes the critical side impact requirements of overall global side regulations and the sensitivity of various side injury parameters on NCAP rating assessment. The federal side impact regulation FMVSS 214 made very stringent by adding oblique pole impact in addition to moving deformable barrier (MDB) test. Though the vehicle velocity is less in oblique pole test, the dynamic intrusions are more which causes severe injury for 5th and 50th %le occupants than MDB test. It was observed that typical injury parameter in side impact requirements is the thorax compression than other injuries, because it is very sensitive than Pelvic, Abdomen regions. To meet these critical injury requirements in side impact, the optimal side restraint system is mandatory in order to develop a safer vehicle with high NCAP score. The side restraint system includes side airbags (thorax and curtain), Hip pusher block/foam padding, door trim arm rest, seat belts and seats.
Technical Paper

Material Model Development of an Energy Absorbing Foam for Occupant Safety

2009-01-21
2009-26-0088
Different Original Equipment Manufacturers (OEMs) use different Finite Element (FE) codes to perform crash analyses. Primary explicit codes widely used are LS-DYNA, PAM-CRASH and RADIOSS. These codes help rapid evaluation of vehicle design in the preliminary phase, eliminating the need for cumbersome design changes post-physical validation trials. This is more so critical for crash and safety aspects of design. A variety of Energy Absorbing (EA) foams are offered to OEMs to meet the EA performance requirements. Also the FE codes offer a variety of standard material models to the analyst to choose from. The choice of material model is governed by factors such as type of foam under consideration, simplicity of modeling, available material test data, performance objectives, etc. The development of a validated material model is hence a complex task. This paper deals with development and validation of material models of IMPAXX for the FE codes RADIOSS and PAM-CRASH.
Technical Paper

Side System Optimisation with MADYMO and mode FRONTIER

2009-01-21
2009-26-0004
Across the world different regulations are applicable for side impact, each require a different restraint system approach. However it would be much more cost effective to develop one single restraint system suitable for all global requirements. An efficient methodology has been developed to optimize the restraint system for multiple load cases simultaneously, resulting in a restraint system specification that will ensure that global targets are met. The methodology combines the use of testing and efficient numerical simulation to find a solution in the most effective way.
Technical Paper

Performance Evaluation of Bus Structure in Rollover as Per ECE-R66 Using Validated Numerical Simulation

2009-01-21
2009-26-0002
A rollover event is one of the most crucial hazards for the safety of passengers and bus drivers. Deformation in bus body structure seriously threatens passengers' lives. European regulation “ECE-R66” is in force to prevent the catastrophic consequences of such rollover accidents from occurring and thereby ensuring passenger safety for buses and coaches. On similar lines, is bus code is also coming into force in India. These regulations establish the requirements for passenger survival space (residual space) after the rollover incident happens. According to said regulations, certification can be obtained either by full-scale vehicle testing, or by a validated numerical simulation. The numerical simulation for bus rollover can be carried out using the non-linear explicit dynamic code LS-DYNA and the deformed structure obtained from the simulation enables engineers to investigate whether there is any intrusion in the passenger survival space along the entire vehicle.
Technical Paper

Frontal System Optimization with MADYMO and mode FRONTIER

2009-01-21
2009-26-0005
Across the world different regulations are applicable for frontal impact, each require a different restraint system approach. However it would be much more cost effective to develop one single restraint system suitable for all global requirements. Flexible and reliable development approach has to be used for quick evaluations of various safety system configurations and conditions. An efficient methodology has been developed to optimize the frontal restraint system for multiple load cases simultaneously, Resultant restraint system specification to specification to meet global targets. The methodology combines the use of testing and MADYMO modelling techniques in combination with advanced DoE (Design of Experiments) analysis to find a solution in the most effective way. An example will be given for a optimised restraint design to meet European and US requirements.
Technical Paper

Dashboard Stiffness Control for Reducing Knee Injury in Frontal Crashes

2009-01-21
2009-26-0006
In frontal crashes, one of the primary reasons for occupant injuries is hard contact with the vehicle interiors. While restraints like airbags, seat belt pre-tensioners etc. help in preventing direct contact of the upper body region; vehicle interiors play a critical role in controlling the lower body region injuries. Knee injuries can be controlled in various ways as follows: Avoiding contact with the dashboard by use of buckle pre-tensioners etc. Using restraints like knee airbags Optimizing the dashboard profile and stiffness at the contact locations All the above options have their own advantages and limitations. This paper explains the effect of dashboard stiffness tuning for controlling knee injuries in a frontal crash. The development methodology and some validation tools are discussed using a case study.
Journal Article

Analysis of Pre-Crash Data Transferred over the Serial Data Bus and Utilized by the SDM-DS Module

2011-04-12
2011-01-0809
The primary function of an airbag control module is to detect crashes, discriminate and predict if a deployment is necessary, then deploy the restraint systems including airbags and where applicable, pretensioners. At General Motors (GM), the internal term for airbag control module is Sensing and Diagnostic Module (SDM). In the 1994 model year, GM introduced its SDM on some of its North American airbag-equipped vehicles. A secondary function of that SDM and all subsequent SDMs is to record crash related data. This data can include data regarding impact severity from internal accelerometers and pre-crash vehicle data from various chassis and powertrain modules. Previous researchers have addressed the accuracy of both the velocity change data, recorded by the SDM, and the pre-crash data, but the assessment of the timing of the pre-crash data has been limited to a single family of modules (Delphi SDM-G).
Technical Paper

A Shoulder Belt Load Cell for Racing Cars

2011-04-12
2011-01-1102
This paper presents the rationale behind the development of a shoulder belt load cell suitable for application in racings cars. The design of the load cell and the operational parameters necessary for a research-quality measurement device for biomechanics research in racing car crashes and the performance of the device in sled tests are described.
Technical Paper

Performance Evaluation of Safety Belt Anchorages: A Correlation Study between Laboratory Experiments and FE Models

2011-04-12
2011-01-1100
Safety belts play a very important role in restraining the occupants in a collision, thereby reducing occupant injuries/ fatalities. Strength of the safety belt anchorages are being evaluated by the passenger car manufacturers as per ECE R14/FMVSS 210. Since 2002, evaluations of safety belt anchorages have become mandatory in India. With increasing pressure to cut the design cycle time, manufacturers are focused on Computer Aided Engineering (CAE) for faster design and validation. The results of a CAE simulation largely depends on the user input and model accuracy. Hence a need arises for establishing a credible correlation between the laboratory test results and the CAE simulation results. This paper discusses such a correlation exercise carried out for safety belt anchorage testing through anchorage deformation mapping (ADM) and floor deformation mapping (FDM).
Technical Paper

Field Effectiveness Calculation of Integrated Safety Systems

2011-04-12
2011-01-1101
The potential of determining the change of injury severity in the accident event taking passive as well as active measures into account at the vehicle (integral systems) are at present limited to pedestrian protective systems. Therefore, an extension of the existing methods for the application with common integral systems (front protection, side protection, etc.) is suggested. Nowadays the effectiveness of passive safety systems is determined in crash tests with very high accident severities. However, approximately 90% of real-world accidents have a lower accident severity as the required crash tests. Thus, this paper will present a method calculating the effectiveness of such an integral system based on real-world accident data. For these reasons, this paper is presenting a method for a more valid prediction of injury severity. The German In-Depth Database GIDAS allows clustering the accident event in relevant car-to-car scenarios.
Technical Paper

Quasi-Static Testing of Tubular Roll Cage and Stock Car Chassis Joints

2011-04-12
2011-01-1105
Since their introduction into NASCAR® (National Association for Stock Car Auto Racing, Inc.) in the early 1950s roll bars have played a vital role in protecting race car drivers from injury during crashes. Just as helmets, seats, seatbelts and a multitude of other safety enhancements have evolved and transformed racing safety, so too have roll bars. From serving as additional bracing in early stock cars, to being the primary chassis and frame system in modern NASCAR vehicles, tubular roll bars have changed dramatically. This paper summarizes extensive quasi-static testing of tubular joints. Test variables included joining method and gusset design. Also described are the material properties, engineering characteristics and joining methods currently used in modern NASCAR vehicle chassis fabrication.
Journal Article

Effects of Safety Belt Pretensioning on ATD Motion in Rigid Fixture Rollover Testing

2011-04-12
2011-01-1118
General Motors conducted a series of subsystem rigid fixture sled rollover tests to evaluate the effects of various safety belt pyrotechnic pretensioners on Anthropomorphic Test Device (ATD) head motion. Twelve tests were conducted using a rigid fixture comprised of a modified compact sport utility vehicle (SUV) body encased in a rigid exoskeleton. The testing simulated the pre-trip/trip, free flight and first roof to ground impact phases of a field representative curb trip initiation rollover crash test with a roof to ground impact angle of approximately 180 degrees. Various combinations of safety belt lap anchor, buckle and retractor pretensioners were tested and film analysis was used to measure trailing side ATD head motion relative to the vehicle. Additionally, a new analysis technique of measuring the reduction of lap webbing length during the crash event was developed for evaluating the ability of a restraint system to reduce ATD head motion during the rollover tests.
Technical Paper

Safety Belt and Occupant Factors Influencing Thoracic & Upper Abdominal Injuries in Frontal Crashes

2011-04-12
2011-01-1129
This paper reports on a study that examines the effect of shoulder belt load limiters and pretensioners as well as crash and occupant factors that influence upper torso harm in real-world frontal crashes. Cases from the University of Michigan International Center for Automotive Medicine (ICAM) database were analyzed. Additional information was used from other databases including the National Highway Traffic Safety Administration (NHTSA) New Car Assessment Program (NCAP), the Insurance Institute for Highway Safety (IIHS), the National Automotive Sampling System - Crashworthiness Data System (NASS-CDS), and patient data available from the University of Michigan Trauma Center. The ICAM database is comprised of information from real-world crashes in which occupants were seriously injured and required treatment at a Level 1 Trauma Center.
Technical Paper

Evaluation of Truck Driver Safety in Various Crash Scenarios

2013-01-09
2013-26-0029
Driver safety is one of the key considerations in truck design and development. Virtual simulation offers opportunities to reduce development time and the number of physical prototypes consumed for design verification and validation for safety parameters. Thus, the application of virtual simulations of crash has become an integral part of the vehicle development process. The continuously emerging scenarios involving challenging test requirements can only be tested by means of virtual simulation techniques. This paper presents simulations that are performed to verify various safety aspects to ensure crashworthiness of the truck cabin. The cabin structure was evaluated for various national/international safety regulations. The FE model and simulation methodology was validated through physical testing and correlated for frontal impact test and roof strength test as per AIS 029/ECE R29. Analysis performed to ensure compliance to upcoming regulation ECE R29 Revision 03 is also discussed.
Technical Paper

Challenges in Selection of Restraints Sensing Configurations in Context of Real World Applications

2013-01-09
2013-26-0028
Restraints systems (airbags and seat belts) have been proven to be very effective in occupant protection in crashes. Timely deployment of these devices is very essential for meeting performance requirements. Precision and reliability in restraints deployments demand selection of a robust sensing configuration that caters to the wide variations of real world. This paper highlights complexities involved in engineering of restraints sensing configurations through different case studies on vehicle programs. The paper explains the need for restraints sensing configuration optimization and well defined sensing strategies for a robust solution in real world. A methodology is discussed to achieve good discrimination between crashes of different types and severities. Virtual and physical test data collected at different stages of vehicle development is used. It is found that criteria for threshold levels in restraints sensing requires efforts to identify real world usage variations.
Technical Paper

Performance Driven Package Feasibility of Side Restraints Using KBE Tools

2013-01-09
2013-26-0027
Integrating safety features may lead to changes in vehicle interior component designs. Considering this complexity, design guidelines have to take care of aspects which may help in package feasibility studies that consider systems performance requirements. Occupant restraints systems for protection in side crashes generally comprise of Side Airbag (SAB) and Curtain Airbag (IC). These components have to be integrated considering design and styling aspects of interior trims, seat contours and body structure for performance efficient package definition. In side crashes, occupant injury risk increases due to hard contact with intruding structure. This risk could be minimized by cushioning the occupant contact through provision of SAB and Inflatable IC. This paper explains the methodology for deciding the package definitions using Knowlwdge Based Engineering (KBE) tools.
Technical Paper

Enhanced Light Weight Frontal Crash Box Design for Low Speed and Insurance Tests

2013-01-09
2013-26-0023
Single body architecture designed for various global markets and subjected to varied load cases is a challenge for Body in White (BIW) engineers. Optimization of structural design to meet regulatory, insurance and assessment requirements is an iterative and time consuming task. With focus on reduction of vehicle's damageability and ease of repairability Original Equipment Manufactures (OEM), insurance companies and Research Council for Automobile Repairs (RCAR) [1] are striving for better designs. A space constraint crash box structure installed behind the bumper plays a significant role in absorption of energy, before transmitting to longitudinal rails. In this study, crashworthiness of a multipurpose crash box for a hatch segment vehicle is presented with the various design of experiments conducted with a focus on light weighting, cost and ease of manufacturing.
Technical Paper

New Articulated Safety Bar Project for Cab-Over Trucks

2013-10-07
2013-36-0228
On cab-over trucks to access the engine and others components it is necessary to tilt the cab. This is a regular procedure done several times during the vehicle life cycle. In order to make it easier and safer for mechanical tilting system, it was developed an articulated safety bar to sustain and maintain the cab on the open position. On the current bars available in the market, to close the cab it is necessary that the operator get under the cab to disengage the safety bar. This procedure puts the operator under risk because an accident can happen while the disengagement and the cab can close over him. Thinking on that and looking for a better ergonomic and safety situation, the objective of this work is to present a new articulated safety bar that the engagement and disengagement is done automatically with the natural tilting movement of the cab. This solution was developed at Iveco Latin America for adoption on the new Vertis HD and is under patent process.
Journal Article

Modeling of Adaptive Energy Absorbing Steering Columns for Dynamic Impact Simulations

2014-04-01
2014-01-0802
The objective of this paper focused on the modeling of an adaptive energy absorbing steering column which is the first phase of a study to develop a modeling methodology for an advanced steering wheel and column assembly. Early steering column designs often consisted of a simple long steel rod connecting the steering wheel to the steering gear box. In frontal collisions, a single-piece design steering column would often be displaced toward the driver as a result of front-end crush. Over time, engineers recognized the need to reduce the chance that a steering column would be displaced toward the driver in a frontal crash. As a result, collapsible, detachable, and other energy absorbing steering columns emerged as safer steering column designs. The safety-enhanced construction of the steering columns, whether collapsible, detachable, or other types, absorb rather than transfer frontal impact energy.
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