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Light-weighting of vehicles is one of the challenges for transportation industry due to the increasing pressure of demands in better fuel economy and environment protection. Advanced high strength steels (AHSS) are considered as prominent material of choice to realize lightweight auto body and structures at least in near term. Stamping of AHSS with conventional die materials and surface coatings, however, results in frequent die failures and undesired panel surface finish. A chromium nitride (CrN) coating with plasma nitriding case hardened layer on a die material (duplex treatment) is found to offer good wear and galling resistances. The coating failure initiates from fatigue cracking on the coating surface due to cyclic sliding frictions. In this work, cyclic inclined sliding wear test was used to imitate a stamping process for study on development of coating fatigue cracking, including crack length and spacing vs. sliding-cycles and sliding energy densities.

ISO 26262 was established in 2011 as a functional safety standard for passenger cars. In this standard, ASILs (Automotive Safety Integrity Levels) representing safety levels for passenger cars are determined by evaluating the hazardous events associated with each item constituting an electrical and/or electronic safety-related system according to three evaluation criteria including injury severity. On the other hand, motorcycles will be included in the scope of application of ISO 26262 in the next revision. It is expected that a severity evaluation for motorcycles will be needed because motorcycles are clearly different from passenger cars in vehicle mass and structure. Therefore, this study focused on severity class evaluation for motorcycles. A method of classifying injury severity according to vehicle speed was developed on the basis of accident data.

One of the major challenges in multiobjective, multidisciplinary design optimization (MDO) is the long computational time required in evaluating the new designs' performances. To shorten the cycle time of product design, a data mining-based strategy is developed to improve the efficiency of heuristic optimization algorithms. Based on the historical information of the optimization process, clustering and classification techniques are employed to identify and eliminate the low quality and repetitive designs before operating the time-consuming design evaluations. The proposed method improves design performances within the same computation budget. Two case studies, one mathematical benchmark problem and one vehicle side impact design problem, are conducted as demonstration.

Since their inception, the design of airbag sensing systems has continued to evolve. The evolution of air bag sensing system design has been rapid. Electromechanical sensors used in earlier front air bag applications have been replaced by multi-point electronic sensors used to discriminate collision mechanics for potential air bag deployment in front, side and rollover accidents. In addition to multipoint electronic sensors, advanced air bag 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 air bag system algorithms and occupant protection deployment strategies. Electronic sensing systems have allowed for the advent of event data recorders (EDRs), which over the past decade, have provided increasingly more information related to air bag deployment events in the field.

High silicon molybdenum (HiSiMo) ductile cast iron (DCI) is commonly used for high temperature engine components, such as exhaust manifolds, which are also subjected to severe thermal cycles during vehicle operation. It is imperative to understand the thermomechanical fatigue (TMF) behavior of HiSiMo DCI to accurately predict the durability of high temperature engine components. In this paper, the effect of the minimum temperature of a TMF cycle on TMF life and failure behavior is investigated. Tensile and low cycle fatigue data are first presented for temperatures up to 800°C. Next, TMF data are presented for maximum temperatures of 800°C and minimum cycle temperatures ranging from 300 to 600°C. The data show that decreasing the minimum temperature has a detrimental effect on TMF life. The Smith-Watson-Topper parameter applied at the maximum temperature of the TMF cycle is found to correlate well with out-of-phase (OP) TMF life for all tested minimum temperatures.

Pending reductions in light duty vehicle PM emissions standards from 10 to 3 mg/mi and below will push the limits of the gravimetric measurement method. At these levels the PM mass collected approaches the mass of non-particle gaseous species that adsorb onto the filter from exhaust and ambient air. This introduces an intrinsic lower limit to filter based measurement that is independent of improvements achieved in weighing metrology. The statistical variability of back-up filter measurements at these levels makes them an ineffective means for correcting the adsorption artifact. The proposed subtraction of a facility based estimate of the artifact will partially alleviate the mass bias from adsorption, but its impact on weighing variability remains a problem that can reach a significant fraction of the upcoming 3 and future 1 mg/mi standards. This paper proposes an improved PM mass method that combines the gravimetric filter approach with real time aerosol measurement.

Advanced high strength steels (AHSS) have been widely accepted as a material of choice in the automotive industry to balance overall vehicle weight and stringent vehicle crash test performance targets. Combined with efficient use of geometry and load paths through shape and topology optimization, AHSS has enabled vehicle manufacturers to obtain the highest possible ratings in safety evaluations by the Insurance Institute for Highway Safety (IIHS) and the National Highway Traffic Safety Administration (NHTSA). In this study, vehicle CAE side impact models were used to evaluate three side impact crash test conditions (IIHS side impact, NHTSA LINCAP and FMVSS 214 side pole) and the IIHS roof strength test condition and to identify several key components affecting the side impact test performance. HyperStudy® optimization software and LS-DYNA® nonlinear finite element software were utilized for shape and gauge optimization.

Analytical models (math or computer simulation models) are typically built on the basis of many assumptions and simplifications and hence model prediction could be inaccurate in intended applications. Model validation is thus critical to quantify and improve the degree of accuracy of these models. So far, little work considers model validation for various design configurations so that model prediction is accurate in the intended design space. Furthermore, there is a lack of effective approaches that can be used to quantify model accuracy considering different number of experimental data. To overcome these limitations, objective of this paper is to develop a model validation approach for various design configurations with a reference metric for model accuracy check considering different number of experimental data.

This study demonstrates the use of pressure sensing technology to predict the crash severity of frontal impacts. It presents an investigation of the pressure change in the front structural elements (bumper, crush cans, rails) during crash events. A series of subsystem tests were conducted in the laboratory that represent a typical frontal crash development series and provided empirical data to support the analysis of the concept. The pressure signal energy at different sensor mounting locations was studied and design concepts were developed for amplifying the pressure signal. In addition, a pressure signal processing methodology was developed that relies on the analysis of the air flow behavior by normalizing and integrating the pressure changes. The processed signal from the pressure sensor is combined with the restraint control module (RCM) signals to define the crash severity, discriminate between the frontal crash modes and deploy the required restraint devices.

Gas Metal Arc Welding (GMAW) is widely employed for joining relatively thick sheet steels in automotive body-in-white structures and frames. The GMAW process is very flexible for various joint geometries and has relatively high welding speed. However, fatigue failures can occur at welded joints subjected to various types of loads. Thus, vehicle design engineers need to understand the fatigue characteristics of welded joints produced by GMAW. Currently, automotive structures employ various advanced high strength steels (AHSS) such as dual-phase (DP) and transformation-induced plasticity (TRIP) steels to produce lighter vehicle structures with improved safety performance and fuel economy, and reduced harmful emissions. Relatively thick gages of AHSS are commonly joined to conventional high strength steels and/or mild steels using GMAW in current body-in-white structures and frames.

In the North American automotive industry, various advanced high strength steels (AHSS) are used to lighten vehicle structures, improve safety performance and fuel economy, and reduce harmful emissions. Relatively thick gages of AHSS are commonly joined to conventional high strength steels and/or mild steels using Gas Metal Arc Welding (GMAW) in the current generation body-in-white structures. Additionally, fatigue failures are most likely to occur at joints subjected to a variety of different loadings. It is therefore critical that automotive engineers need to understand the fatigue characteristics of welded joints. The Sheet Steel Fatigue Committee of the Auto/Steel Partnership (A/S-P) completed a comprehensive fatigue study on GMAW joints of both AHSS and conventional sheet steels including: DP590 GA, SAE 1008, HSLA HR 420, DP 600 HR, Boron, DQSK, TRIP 780 GI, and DP780 GI steels.

There has been a substantial increase in the use of advanced high strength steel (AHSS) in automotive structures in the last few years. The usage of these materials is projected to grow significantly in the next 5-10 years with the introduction of new safety and fuel economy regulations. AHSS are gaining popularity due to their superior mechanical properties and use in parts for weight savings potential, as compared to mild steels. These new materials pose significant manufacturing challenges, particularly for welding and stamping. Proper understanding of the weldability of these materials is critical for successful application on future vehicle programs. Due to the high strength nature of AHSS materials, higher weld forces and longer weld times are often needed to weld these advanced strength steels.

Ferrocene is used as an antiknock additive to replace lead alkyls. To clarify the influence of one metal additive, ferrocene, on engine, following experiments were carried out. The insulation resistance of spark plugs was measured, deposits in the engine were analyzed, and an exhaust emission and fuel economy tests were conducted using gasoline containing ferrocene. The deposit, which contained iron oxides, adhered to the combustion chamber, spark plugs, and exhaust pipe when the engine operated with gasoline containing ferrocene. When vehicles operated with gasoline containing ferrocene, fuel consumption increased and the exhaust temperature rose. In addition, an abnormal electrical discharge pattern was observed in spark plugs operating at high temperatures. Iron-oxide of Fe3O4 is changed into Fe2O3 under high temperatures. Discharge current flows in iron oxides including Fe2O3 because the conductivity of Fe2O3 increases at high temperatures.

Frontal vehicle collisions often result in foot injury of the front seat occupant. Therefore, it is very important to understand the mechanism of the foot injury. For that purpose, several impact experiments have been conducted using a partial human lower extremity. In addition, recently several impact response analyses using a human FE model have been conducted to understand the mechanism. In the present circumstances, a verified FE model is needed, and the verification of kinematical biofidelity is very important in the first place. In this connection, a foot FE model (based on an existing human FE model) was improved to create a foot FE model, which can be used for study of foot injury mechanism in this research. And the kinematics of foot bones of the model was verified by comparing the bone movements of the FE model with the movement of human foot during heel impact.

The strength of the passenger compartment is crucial for occupant safety in severe car-to-car frontal offset collisions. Car-to-car crash tests including minicars were carried out, and a low end of crash force was observed in a final stage of impact for cars with large intrusion into the passenger compartment. From overload tests, the strength could be evaluated from collapsing the passenger compartment. Based on the test, the end of crash force as well as the maximum forces might be important criteria to determine the passenger compartment strength, which in turn could predict the large intrusion into the passenger compartment in car-to-car crashes. A 64 km/h ODB test was insufficient to evaluate the potential strength of the passenger compartment because the maximum forces could not be determined in this test.

Single cylinder engine testing was carried out to clearly understand the test results of multi-cylinder engines reported by the Diesel WG in JCAP (Japan Clean Air Program) (1), (2), (3) and (4). In this tests, engine specifications such as fuel injection pressure, nozzle hole diameter, turbo-charging pressure, EGR rate, and fuel properties such as 1-, 2-, 3-ring aromatics content, n-,i-paraffins content, and T90 were parametrically changed and their influence on the emissions were studied. PM emission generally increased in each engine condition with increased aromatic contents and T90. In particular, multi ring aromatics brought about large increases in PM regardless of the engine conditions. The influence of fuel properties on NOx emission is smaller than the influence on PM emission. Some other fuels that have various side chain structures of 1-ring aromatics, normal paraffins only and various naphthene contents were also investigated.

The New Car Assessment Program in Japan (JNCAP) was launched in 1995 in order to improve car safety performance. According to this program, installation conditions of safety devices and the results for braking performance and full- frontal crash tests are published every year. Introduction of JNCAP significantly increases the installation rate of safety devices and contributes much in enhancement of safety as seen in the decrease in the average injury severity of drivers and passengers. Side impact and offset frontal crash tests were introduced in 1999 and 2000, respectively. At present, the overall crash safety rating is carried out based on the results of the full-frontal, offset frontal, and side impact tests.

This paper summarizes a future side impact test procedure based on the Japanese presentation at the recent IHRA Side Impact WG meeting. Under current Japanese regulations, the MDB specifications and test procedures were determined based on a market study more than ten years ago. Thus, they may not reflect current automobile characteristics, the actual accident situation, and crash test results. In this study (1) the vehicle types, velocity of striking and struck vehicles, body injury regions, causes of injuries, etc., are reviewed with reference to the latest Japanese side impact accident data. The occupant percentages for the non-struck-side, rear seat and for female occupants as well as the injury levels were analyzed. (2) To determine the MDB specifications, based on data from passenger car models registered in 1998, the curb mass, geometry and stiffness were examined. (3) For factorial analysis, side impact tests were performed as for real accidents.

The Japan New Car Assessment Program (JNCAP) was launched in 1995 in order to improve car safety performance. According to this program, installation conditions of safety devices and the results for braking performance and full- frontal crash test are published every year. The side impact test was introduced in 1999. In 2000, the offset frontal crash test was also introduced. From the viewpoint of such a diversification of the crash tests, an overall assessment method for the safety of cars which reflects road accidents has been demanded. In this study, we have examined a new overall assessment method capable of reflecting the traffic accident situation in Japan using methods employed or planned by USA-NCAP, Euro-NCAP, TUB-NCAP and others as references. As the basic concept, JNCAP conducts three types of crash tests including the full-frontal crash test, offset frontal crash test, and side impact test to assess the dummy injury parameters.

Guidelines with regard to the body strength of buses have been drawn up in Japan. We now pass to the second step in research to assure the greater safety of bus crews and passengers by launching a study on further reduction of collision injuries to bus occupants. As a way to reduce such passenger injuries, our focus is the optimization of energy absorption, the arrangement of equipment on the passenger seat back, the seat frame construction, mounting and so on. The study was conducted using an experimental method together with FEM computer simulation. The findings from a sled impact test simulating a seat in a bus in a frontal collision are stated as follows. 1.Further consideration should be given to the present conventional ELR two-point seat belt. 2.One way to reduce passenger injury is to optimize the space between seats.