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This paper summarises the results of a project on vehicle crash compatibility, run by European automotive industry together with some research institutes. The project was funded by the European commission as BE97-4049. There are three main issues that can be detected in real world accidents, influencing vehicle compatibility. These issues are mass differences, compartment integrity with regard to frontal car-to-car impact, and differences in bumper and sill height in side impact. Longitudinal mismatch in frontal impact, front end stiffness and other items which are from a theoretical point of view responsible for vehicle aggressiveness are not seen influential from the view point of real world accidents. On the other hand, compartment collapse occurs, when there is not sufficient deformation energy available in vehicle front-end. And deformation energy is available, when it is provided by vehicle structures and when these structures interact.

The relationship between designing for both rigid fixed barrier (RFB) and vehicle-to-vehicle tests is a topical area of research. Specifically, vehicle-to-vehicle compatibility has been a topic of keen interest to many researchers, and the interplay between the two aspects of design is presently addressed. In this paper, the studied vehicles for potential vehicle-to-vehicle impacts included: sport utility vehicles (SUVs), Pickups (PUs), and passenger cars. The SUV/PU-to-Car frontal impact tests were compared to those obtained from vehicle-to-rigid fixed barrier frontal impacts. Acceleration pulses at the B-pillar/rocker as well as dash and cabin intrusions were monitored and compared. Additionally, the energy distributions in SUV/PU-to-Car crash tests were compared to those of single vehicle-to-RFB tests. It was concluded from the analysis that vehicle weight and front-end stiffness were not always the overriding factors dictating performance.

Over the recent years, tests have been developed which will result in higher levels of protection afforded to pedestrians involved in vehicle impacts. These requirements will result in improved vehicles, which are designed to be safer and less harmful to pedestrians. The requirements include a series of impact tests into the front end of a vehicle with a variety of instrumented forms including an adult headform, a child headform, as well as an upper legform and a complete legform. Although the requirements have not been finalized, it is expected that they are to become part of the European homologation test series soon. Automobile manufacturers that sell cars in Europe are beginning to incorporate the proposed regulations into new car designs.

Light truck vehicles (LTVs), sport utility vehicles (SUVs), and vans collectively make up a growing segment of the total automotive fleet sales, particularly in the United States. The National Highway Traffic Safety Administration (NHTSA) has identified this trend and has increased the extent of its research in vehicle-to-vehicle compatibility. Additionally, vehicle compatibility concerns have also been emphasized by International Harmonization Research Activity (IHRA). Accordingly, with intention to further enhance road safety, research in the area of crash compatibility between cars and LTVs in different crash configurations is of significant importance. This paper describes a part of ongoing research at Ford Motor Company to further investigate the effect of compatibility in SUV/LTV-to-Car crashes.

Since 1995, the Insurance Institute for Highway Safety (IIHS) has evaluated the crashworthiness of more than 120 new vehicle models in a 64 km/h (40 mi/h), 40 percent offset deformable barrier crash test. The offset test is especially demanding of the vehicle structure, requiring only 40 percent of the vehicle width to manage the crash energy. Many of the models originally tested have been redesigned and retested, with the majority producing better structural performance than their predecessors. Critics of such testing have suggested that these tests are forcing vehicle stiffness too high for compatibility with other vehicles and other crash modes. IIHS has studied the relationship between vehicle mass, stiffness, and front-end length to the structural rating in the offset test.

The issue of vehicle incompatibility, especially between passenger cars and utility vehicles/pickup trucks, has received a lot of attention in recent years. Real-world crash data show that occupants of cars are much more likely to be injured in frontal crashes with utility vehicles and pickup trucks than with other passenger cars, even after controlling for vehicle mass. Factors in addition to mass that can influence compatibility are stiffness and geometry. In this paper, the effects of these factors on occupant injury measures and vehicle deformation patterns are examined. The Insurance Institute for Highway Safety conducted a series of car-to-utility-vehicle frontal offset tests with the Ford Taurus as a common collision partner. To vary stiffness, the Taurus collided with either a Mercedes ML320 or a relatively stiffer Isuzu Rodeo.

The work reported here forms part of a research project that is being undertaken to further the understanding of compatibility in car-to-car collisions and develop crash evaluation procedures that are suitable for consumer and legislative testing. For frontal impact, full-scale crash testing, accident analysis case studies and supportive finite element modelling studies have been used to identify the major factors that influence compatibility. One result is that the geometrical interaction of car structures has a large effect and it is now believed that obtaining good structural interaction is an essential prerequisite for frontal impact compatibility. Having achieved this, the next step is to control the global stiffness of the cars to ensure that they are able to absorb the collision energy, with minimal occupant compartment intrusion, without compromising the vehicle's deceleration pulse profile.

Pedestrian crash kinematics have been well documented for automobile versus pedestrian collisions. However, there is not significant amount of data concerning impact of pedestrians with a high profile vehicle. A series of pedestrian crash tests using full-sized vans was performed to add to the existing database of forward projection pedestrian collisions and to compare the crash test data to existing forward throw equations. The aim of this study was to examine the trajectory behavior of the pedestrian in a forward projection impact and the effect of different friction-value surfaces when applying a pedestrian model to the data. In performing the tests, the pedestrian dummy was stabilized using an 18.2 kg tensile strength monofilament wire hanging from a cantilever beam. The impacting vans were instrumented with a triaxial accelerometer triggered at impact with the dummy. Several testing surfaces were used, ranging from dry asphalt to a skidpad with > 1/16th inch depth of water.

Test procedures for evaluating vehicle compatibility were investigated based on accident analysis and crash tests. This paper summarizes the research reported by Japan to the IHRA Compatibility Working Group. Passenger cars account for the largest share of injuries in head-on collisions in Japan and were identified as the first target for tackling vehicle compatibility in Japan. To ascertain situations in collisions between vehicles of different sizes, we conducted crash tests between minicars and large cars, and between small cars and large cars. The deformation and acceleration of the minicar and small car is greater than that of large car. ODB, Overload and MDB tests were performed as procedures for evaluating vehicle compatibility. In overload tests, methods to evaluate the strength of the passenger compartment were examined, and it is found that this test procedure is suitable for evaluating the strength of passenger compartments.

In this paper, the results from a matrix of tests performed to evaluate the response of the occupant injuries in collisions between passenger cars at 55 km/h are reviewed. Various crash tests were conducted with different vehicle weights and stiffness to investigate the effect of body intrusion and vehicle deceleration on occupant injuries. Some cases showed high intrusion which resulted in high occupant injury. Conversely some cases exhibited severe body deceleration which resulted in high occupant injury. In the cases with severe body deceleration, the body intrusion was almost the same as a 64 km/h ODB test but the injuries occur because the body deceleration is much greater in the car-to-car collision than the ODB test. To assess vehicle compatibility, an MDB test method is proposed which is one of the representative test methods of real world car-to-car accidents.

A systems modeling approach is presented for assessment of harm in the automotive crash environment. The recent surge in light truck sales has highlighted the need to evaluate these vehicles’ aggressivity in two-vehicle crashes while also considering potential self protection benefits in single-vehicle crashes. The methodology consists of parametric simulation of several controlled accident variables, with case results weighted by the relative frequency of each specific event. A hierarchy of models is proposed, consisting of a statistical model to define the crash environment and assign weighting factors for each crash situation case, and vehicle models for parametric simulation of crash events. Approximating functions are utilized to estimate occupant harm metrics based on vehicle crash response. Head and chest injury results for each case are converted to harm vectors, in terms of probabilistic Abbreviated Injury Scale (AIS) distributions.

A major focus of the National Highway Traffic Safety Administration's (NHTSA) vehicle compatibility and aggressivity research program is the development of a laboratory test procedure to evaluate compatibility. This paper is written to explain the associated goals, issues, and design considerations and to review the preliminary results from this ongoing research program. One of NHTSA's activities supporting the development of a test procedure involves investigating the use of an mobile deformable barrier (MDB) into vehicle test to evaluate both the self-protection (crashworthiness) and the partner-protection (compatibility) of the subject vehicle. For this development, the MDB is intended to represent the median or expected crash partner. This representiveness includes such vehicle characteristics as weight, size, and frontal stiffness. This paper presents distributions of vehicle measurements based on 1996 fleet registration data.

Evaluation of car front aggressiveness in car-pedestrian accidents is typically done using sub-system tests. Three such tests have been proposed by EEVC/WG17: 1) the legform to bumper test, 2) the upper legform to bonnet leading edge test, and 3) the headform to bonnet top test. These tests were developed to evaluate performance of the car structure at car to pedestrian impact speed of 11.1 m/s (40 km/h), and each of them has its own impactor, impact conditions and injury criteria. However, it has not been determined yet to what extent the EEVC sub-system tests represent real-world pedestrian accidents. Therefore, there are two objectives of this study. First, to clarify the differences between the injury-related responses of full-scale pedestrian dummy and results of sub-system tests obtained under impact conditions simulating car-to-pedestrian accidents. Second, to propose modifications of current sub-system test methods. In the present study, the Polar (Honda R&D) dummy was used.

This paper will describe an approach to satisfying proposed European Enhanced Vehicle Safety Committee (EEVC) legislation for lower leg pedestrian impact. The solution for lower leg protection is achieved through a combination of material properties and design. Using Computer Aided Engineering (CAE) modeling, the performance of an energy absorber (EA) concept was analyzed for knee bending angle, knee shear displacement, and tibia acceleration. The modeling approach presented here includes a sensitivity analysis to first identify key material and geometric parameters, followed by an optimization process to create a functional design. Results demonstrate how an EA system designed with a polycarbonate/polybutyelene terephthalate (PC/PBT) resin blend, as illustrated in Figure 1, can meet proposed pedestrian safety requirements.

In this study, the comparative stiffness of vehicle side and frontal structures is determined by available static test and crash test data. NHTSA has conducted a series of staged crash tests where a Honda Accord is impacted by different bullet vehicles at a closing velocity of 32.5 mph. These staged front-to-side crash tests are examined to assess the extent of damage to both the bullet and struck vehicle. The load cell barrier data for the bullet vehicles used in NHTSA's vehicle-to-vehicle front-to-side crash tests are examined to determine the geometric and stiffness properties of the frontal structures as measured in the NCAP tests. The geometric and stiffness measurements during the early stages of frontal crush are most influential in front-to-side crashes. The barrier data provides useful stiffness information. However, the number of rows of load cells may be insufficient to provide geometric information.

X-by-Wire systems are expected to enhance vehicle driving performance and safety. This paper describes an electronic platform architecture for X-by-Wire systems that satisfies both cost-effectiveness and dependability. In the first part of this paper (Part 1), we have proposed a new electronic architecture based on a concept of autonomous decentralized systems. In the latter part (Part 2), the proposed architecture implementation to the actual vehicle control systems will be discussed. We clarify that, due to system level redundancy the proposed architecture provides, vehicle control systems can basically consist of low cost fail-silent nodes. Furthermore, for cost optimization, considering a tradeoff between hardware cost and fault detection coverage, we design a suitable hardware architecture for each node according to node function.

The amount of software integrated into today's vehicles growths exponential and tends to be a patchwork of non interrelated applications. However the interrelationship gets more and more intensive as applications start to cooperate and therefore communicate with each other. By introducing a domain exceeding middleware concept we want applications to experience a high level of integration and enable outsourcing of features applications have in common.

A promising technology for active safety is “X-by-Wire”, where mechanical and electromechanical components are replaced by electronic functions. One of the reasons for this is to have more than the driver input in the command chain, and also include some degree of intervention by the control system in case the driver behaviour is likely to put the car at risk. The adoption of a small number of computing nodes is a clear trend in vehicle design. A wide range of functions that are now distributed in the form of separate modules will instead be integrated. This approach will overcome the physical constraints of electrical and mechanical components and the costs of many separate electronic modules with their own power supplies.

The X-By-Wire (XBW) is one of the promising technologies for integrated vehicle dynamics control system for the next-generation. The system, in view of ECU architecture, combines multiple ECUs by a high-speed. In this, however, the failure of one ECU leads to system-wide failure. To avoid it, all the ECUs have to be fault tolerant, which is not a realistic solution in terms of cost. We propose a concept for a cost-effective and fault tolerant vehicle control architecture for real-time and scalable X-by-Wire systems. The concept is based on the Autonomous Decentralized Systems [1][2]. The features of the proposed concept are a shared data-field, self-operation, self-check, and self-backup. The proposed architecture will realize a fault-tolerant system without making all the subsystems fault-tolerant.

As systems necessarily become more integrated and increasingly complex through market demands for more features, technical risks and therefore business risks increase. It becomes correspondingly harder to show that the properties desired of these Systems of Systems (SoS) actually hold under normal or abnormal operation. In particular, it is hard to detect emergent properties of a SoS because properties of individual systems are not necessarily compositional, especially during failure. This paper describes the objectives of a project addressing the problem of Dependable System of Systems and other related research in the field of Automotive Electronics. The capability being developed is based upon the scalable ‘Assumption-Commitment’[1] paradigm so that it can be applied to large and complex systems of systems.