Engineering Challenges in Alloy Wheel Rim for Safety Simulations

<div class="section abstract"> <div class="htmlview paragraph">This SAE Recommended Practice provides common data output formats and definitions for a variety of data elements that may be useful for analyzing the performance of automated driving system (ADS) during an event that meets the trigger threshold criteria specified in this document. The document is intended to govern data element definitions, to provide a minimum data element set, and to specify a common ADS data logger record format as applicable for motor vehicle applications.</div> <div class="htmlview paragraph">Automated driving systems (ADSs) perform the complete dynamic driving task (DDT) while engaged. In the absence of a human “driver,” the ADS itself could be the only witness of a collision event. As such, a definition of the ADS data recording is necessary in order to standardize information available to the accident reconstructionist. For this purpose, the data elements defined herein supplement the SAE J1698-1 defined EDR in order to facilitate the determination of the background and events leading up to a collision in an ADS-operated vehicle.</div> <div class="htmlview paragraph">The data elements defined in this document are unique to Level 3, 4, or 5 ADS features, as defined by SAE J3016, and provide additional background of the events leading up to a crash or crash-like event. The data from sensors such as camera(s), LiDAR(s) etc. will provide information in the absence of a human driver. The data included in the ADS data logger is expected to be used in conjunction with the SAE J1698 event data recorder (EDR) record and traditional accident reconstruction analysis. The EDR and ADS data logger will capture information leading up to the triggered event, at a minimum. There are no facts to support that recording data for greater than 5 seconds pre-event would change the outcome of any crash analysis. Thus, the recommended recording duration for a data logger is 5 seconds pre-event, same as an EDR. Due to the potential for sensor and/or communication failure during a crash event, the recommendation is that data should be collected post-crash for impact and rollover sensors for up to 250 ms.</div> <div class="htmlview paragraph">ADS technology is still being developed and is not yet commercially deployed. Therefore, this SAE Recommended Practice is intended as a guide toward standard practice and is subject to change to keep pace with experience and technical advances.</div> </div>

An Efficient Algorithm for Operating on Large Numbers of Aggregate Particles with Applications to Simulating the Dynamics of Irregularly Shaped Grains

<div class="section abstract"><div class="htmlview paragraph">Strength, creep, and fatigue of the chassis components are greatly influenced by the material used and its manufacturing process. Alloy wheel is one of the critical chassis components manufactured using the casting process. Secondary Dendrite Arm Spacing (SDAS) is one of the important microstructural parameters generated during the solidification stage of the casting process. SDAS has a significant role in altering the mechanical properties and the behavior of the component. Variation in solidification time and alloy composition will have a major impact in SDAS. The combined effect of SDAS with microstructural variations and the strength behavior has not been studied in earlier literature for an alloy wheel.</div><div class="htmlview paragraph">The scope of this study is to perform casting simulation for an alloy wheel, predict the SDAS and capture the variation of mechanical properties (yield strength, ultimate tensile strength & elongation). Further a few casting simulations were carried out by changing the solidification time and alloy composition to predict the variation of SDAS and its relationship with mechanical properties. The effect of SDAS on strength behavior of the wheel is studied by wheel simulation and correlated with test results.</div></div>

<div class="section abstract"><div class="htmlview paragraph">Crush box in an automotive passenger car has become an integral part of structural design performing various functions like optimizing energy absorption in high speed impacts, replaceable part during low speed impacts etc. Design of crush box for high speed impacts is very important as it is the first major energy absorbing component in the load path and its deformation significantly affects the overall vehicle crash behavior.</div><div class="htmlview paragraph">The present paper explains development of a hydro-formed crush box in the front end of a sports utility vehicle. Hydro-formed components have residual plastic strains and non - uniform thickness variation throughout their length which is difficult to measure from a physical test coupon. It is critical to add hydro-forming effects onto crash FE models as it significantly affects the deformation under high speed impact. But detailed forming simulations need mature design and material data which is not available during early phases of product development. Hence, leveraging CAE through front loading, a new method of mapping the residual effects of hydro-forming during early concept phase is proposed in the current study.</div><div class="htmlview paragraph">The crush box was tuned for optimum energy absorption through accordion crush and progressive deformation and was validated through a unique high speed physical test setup resembling impact loading during frontal crash. Results of the proposed mapping technique during early development phase showed good correlation with physical test and matched well with detailed forming processes evaluated during the matured design phase. The designed crush box was tested at full vehicle level for offset crash and good correlation was observed in terms of deformation and load carrying capacity.</div></div>

<div class="htmlview paragraph">Phenolic resins have been widely used as a binder for friction materials. Increased performance requirements have exceeded the capabilities of standard phenolic resins. Various modified phenolic resins have been developed with proven capabilities and performance levels. The impact on the environment and work place must also be considered when developing new products. In addition to improved performance, new phenolic resins for friction applications should also be improved to address environmental and work place issues. In order to achieve further improvement, fundamental studies, such as morphology, are needed.</div> <div class="htmlview paragraph">An EPMA (Electron Probe Micro Analyzer) is useful to identify elements, while former investigations have developed the technology to identify some ingredients in friction materials. However, it has been impossible to show phenolic resin in friction materials since they contain many other ingredients also made from carbon.</div> <div class="htmlview paragraph">Porosity also plays a great role in final properties of friction materials. Therefore, it is important to map porosity in friction materials in addition to mapping phenolic resin.</div> <div class="htmlview paragraph">This paper will review the followings:</div> <div class="htmlview paragraph"> <ul class="list disc"> <li class="list-item"><div class="htmlview paragraph">Technology to show presence and distribution of phenolic resin in friction materials.</div> </li> <li class="list-item"><div class="htmlview paragraph">Map phenolic resins in friction materials.</div> </li> <li class="list-item"><div class="htmlview paragraph">Technology to show presence and distribution of porosity in friction materials.</div> </li> <li class="list-item"><div class="htmlview paragraph">Map the porosity in friction materials.</div> </li> <li class="list-item"><div class="htmlview paragraph">The relationship between the distribution of phenolic resin, porosity, and physical properties.</div> </li> </ul> </div>

<div class="section abstract"><div class="htmlview paragraph">Intersections have a high risk of vehicle-to-vehicle conflicts because of the overlapping traffic flow from multiple roads. To understand the factors contributing to the crashes, this study examines the common characteristics in intersection-related crash and near- crash events, such as the existence of traffic control devices, the driver at fault, and occurrence of visual obstructions. The descriptive data of the crash and near-crash events recorded in the Second Strategic Highway Research Program Naturalistic Driving Study (SHRP 2 NDS) database is used in categorization and statistical analysis in this study. First, the events are divided into seven categories based on trajectories of the conflicting vehicles. The categorization provides the basis for in-depth analysis of crash-contributing factors in specific confliction patterns. Subsequently, descriptive statistics are used to portray each of the categories. The severity of the categories is determined based of the frequency of occurrences of the crashes and near-crashes. Factors contributing to each crash category are then examined based on their frequency of occurrence with the categories. This study reveals the severity of different intersection-related crash patterns, as well as the effects of some crash-contributing factors. The information presented in this paper has the potential to guide investigators interested in developing simulation and test track scenarios to evaluate vehicles equipped with automated driving systems (ADS).</div></div>

<div class="section abstract"><div class="htmlview paragraph">Achieving zero emissions across transportation is a tremendous challenge. The upcoming Euro 7/VII standards, set to be enforced in 2025, will mandate further reduction in ICEs exhaust emissions. Thus, additional improvements and potential new technologies and fuels are needed to design ultra-low emissions vehicles.</div><div class="htmlview paragraph">Hydrogen seems to be a very attractive fuel, thanks to its high lower heating value, clean combustion, and extremely low pollutant emissions, due to the zero-carbon content. Nevertheless, NOx emissions are still an issue in hydrogen fueled engines and optimized lean-burn combustion and suitable after-treatment NOx reduction are mandatory to reach high specific power and efficiency and near zero NOx emissions, thus enabling H2-ICE powered vehicles to be zero-impact emitting technology solution.</div><div class="htmlview paragraph">Selective Catalytic Reduction by using NH3 as the reducing agent is the most effective control technology for NOx abatement. Nevertheless, ongoing research and innovation are critical in developing new strategies for reducing NOx emissions, to overcome the NH3-SCR system main critical issues (extra equipment for urea storage and dosing, ammonia-slip, deactivation and fouling, low efficiency at low temperature).</div><div class="htmlview paragraph">The SCR of NOx by hydrogen is considered a promising alternative to traditional ammonia-based deNOx technology. The H2-SCR catalysts are suitable for engine exhaust after-treatment during cold-start and urban-driving operations, exhibiting higher catalytic activity for low-temperature NOx emissions conversion (180 – 200 °C). Furthermore, in H2-ICE powered vehicles, the additional tank to store the reducing agent is not needed with a significant simplification of the engine exhaust lay-out.</div><div class="htmlview paragraph">Experimental investigations on different H2-SCR catalysts have demonstrated that the conversion activity is greatly affected by the catalytic system configuration, the adsorption properties of the support material, the H2 spillover, that in turn are affected by H2/NO ratio and exhaust gas composition, temperature and flow rate.</div><div class="htmlview paragraph">In the present paper, a feed-forward neural network model of H2-SCR is presented, with the aim of performing real-time estimation of reduction efficiency and supporting the design of suitable H2 management to achieve maximum NOx reduction and minimum hydrogen consumption. Model training and identification are carried out against a large set of experimental data measured on a H2-SCR small scale prototype at the Synthetic Gas Bench. The experimental tests were designed to reproduce the real conditions expected at the exhaust of a H2-fueled engine.</div></div>

<div class="section abstract"><div class="htmlview paragraph">The turn-across-path from opposite-direction [LTAP-OD] crash type contributes to one of the major fatal crash types in young drivers. Drivers responses in police reportable and severe crashes and near crashes involving an LTAP-OD scenario were evaluated from query of the Second Strategic Highway Research Program [SHRP-2]. This research examined the responses of through drivers. 122 such events were analyzed to extract driver braking behavior, secondary tasks, age, and perception-response times. All measures of through driver variables were compared with respect to turning driver behavior. The study aimed to identify the trigger event for drivers to respond to the left turning vehicle. Time to contact was a significant factor which affected driver response times. Drivers responded significantly faster when subjected to shorter time to contact events compared to longer ones. Other short time to contact events included when the turning vehicle did not stop before entering the intersection, or when the turning vehicle was visible for a short duration. Driver factors such as age, gender or secondary task engagement did not significantly influence response times.</div></div>

<div class="section abstract"><div class="htmlview paragraph">This paper focuses on the safety performance of Commercial Vehicle Forward Collision Avoidance and Mitigation Systems (F-CAM) that include Forward Collision Warning (FCW) with Collision Mitigation Braking (CMB) technology as applied to heavy trucks, including single unit and tractor semitrailers.</div><div class="htmlview paragraph">The study estimated the safety benefits of a commercially available F-CAM system considered to be representative of products currently in service. The functional characteristics were evaluated and its performance generically modeled to estimate safety benefits. This was accomplished through the following steps: (1) first characterize the actual performance of these systems in various pre-crash scenarios under controlled test track conditions, and then reverse engineering the algorithms that control warnings and automatic braking actions; (2) developing a comprehensive set of simulated crash events representative of actual truck striking rear-end crashes. This virtual, “reference” crash database was developed by analyzing vehicle interactions (or conflicts) from naturalistic studies to create thousands of crashes in a computer simulation environment; (3) overlaying the F-CAM generic algorithms into the simulations of each crash event and observe the kinematic impacts (i.e., benefits) from having initiated warnings and/or automatic braking (including reduction in impact speed, or crash elimination of the crash).</div><div class="htmlview paragraph">The crash population that could likely benefit from the technologies was identified using nationally representative crash databases. The results from the simulation studies were applied to the national crash population and are presented in terms of crashes avoided, reductions in fatalities, injuries and property damage.</div></div>

<div class="section abstract"> <div class="htmlview paragraph">This SAE Standard describes a laboratory test procedure for measuring the vibration damping performance of a system consisting of a damping material bonded to a vibrating cantilevered steel bar. The bar is often called the Oberst bar (named after Dr. H. Oberst) and the test method is often called the Oberst bar test method. Materials for damping treatments may include homogeneous materials, nonhomogeneous materials, or a combination of homogeneous, nonhomogeneous, and/or inelastic (such as aluminum foil) materials. These materials are commonly installed in transportation systems such as ground vehicles, marine products, and aircraft to reduce vibration at resonance, and thus reduce the noise radiation from the vibrating surface. The test method described herein was developed to rank order materials for application on panels using general automotive steel but also may be applicable to other situations or conditions.</div> <div class="htmlview paragraph">Damping performance for most materials and systems varies as a function of both frequency and temperature. Accordingly, this test procedure includes provisions for measuring damping over a range of frequencies and temperatures found applicable to many transportation systems. The measured damping performance will be expressed in terms of composite loss factor, η<sub>c</sub>, within the frequency range of approximately 100 to 1000 Hz, and over the useful temperature range for the given application. The term composite refers to the steel and damping material combination. The composite loss factor is, therefore, dependent upon the thickness, damping, and modulus of both the steel and damping material layer.</div> <div class="htmlview paragraph">The test procedure described here is based on the method described in ASTM E756. However, this SAE document differs from the ASTM E756 method in that the SAE practice specifies the bar material, three bar sizes, the mounting conditions of the test samples, and suggested standard interpolation frequencies. This document provides a means of rank ordering damping materials according to their composite loss factor values from test samples that represent typical sheet metal applications.</div> <div class="htmlview paragraph">The material properties of the damping material alone, including Young’s modulus E, and the material loss factor η, may be computed from the test samples specified in this document if additional conditions are met. ASTM E756 defines these additional conditions as well as the equations to be used to compute the damping material properties for the single layer (Oberst beam) configuration.</div></div>

<div class="section abstract"><div class="htmlview paragraph">Steering column and steering wheel are critical safety components in vehicle interior environment. Steering system needs to be designed to absorb occupant impact energy in the event of crash thereby reducing the risk of injury to the occupant. This is more critical for non-airbag vehicle versions. To evaluate the steering system performance, Body block impact test is defined in IS11939 standard [<span class="xref">1</span>].</div><div class="htmlview paragraph">Nowadays for product development, CAE is being extensively used to reduce development cycle time and minimize number of prototypes required for physical validation. In order to design the steering system to meet the Body Block performance requirements, a detailed FE model of Body Block impactor is required. The static stiffness and moment of inertia of body block are defined in SAE J244a [<span class="xref">2</span>]. The reference data available in SAE J244a is not sufficient to develop a Body Block model that would represent the physical impactor. This paper details out the work done to develop a FE model of body block impactor from the physical impactor. This includes defining the geometry of impactor, static and dynamic stiffness and it’s stiffness validation with test data. The Body Block model developed was used for a system level evaluation and good correlation was observed with the physical test results with proposed impactor FE model.</div></div>

<div class="section abstract"><div class="htmlview paragraph">One of the most critical elements in engineering a hydrogen fuel cell vehicle is the design of the on-board hydrogen storage system. Because the current compressed-gas hydrogen storage technology has several key challenges, including cost, volume and capacity, materials-based storage technologies are being evaluated as an alternative approach. These materials-based hydrogen storage technologies include metal hydrides, chemical hydrides, and adsorbent materials, all of which have drawbacks of their own. To optimize the engineering of storage systems based on these materials, it is critical to understand the impacts these systems will have on the overall vehicle system performance and what trade-offs between the hydrogen storage systems and the vehicle systems might exist that allow these alternative storage approaches to be viable.</div><div class="htmlview paragraph">To gain a better understanding of the interactions that exist between various materials-based hydrogen storage systems and the vehicle system as well as the engineering challenges that exist when integrating one of these systems with a vehicle, the National Renewable Energy Laboratory (NREL) developed a vehicle-level model designed to be sensitive to these issues. The Hydrogen Storage Simulation Model (HSSIM) was developed under the Hydrogen Storage Engineering Center of Excellence (HSECoE) as a specialized tool that could be used to assist in the design and engineering of materials-based hydrogen storage systems being considered by the HSECoE. This tool is designed to not only allow for understanding key trade-offs, but also to have a seamless integration with the HSECoE fuel cell and detailed hydrogen storage system models and to evaluate progress towards the U.S. Department of Energy's hydrogen storage technical targets. This model has been integrated with a fuel cell model developed by Ford Motor Company in a HSECoE common modeling framework developed by United Technologies Research Center and other HSECoE partners.</div><div class="htmlview paragraph">This paper focuses on the development, structure, and validation of the vehicle model HSSIM and summarizes its integration within the framework. HSSIM and the framework are then used to obtain trade-offs for various specific materials-based storage system designs. This includes hydrogen storage sizing analyses, mass compounding analyses, range versus volume studies, and vehicle and component performance analyses, such as acceleration rates and fuel cell and energy storage interactions.</div></div>

<div class="section abstract"><div class="htmlview paragraph">IT is only since World War ll that extensive study has been made of the effects of high-energy radiation on materials. However, a lack of fundamental data still prevents the making of any generalizations or detailed calculations of the effects of radiation-induced defects on the bulk properties of metals.</div><div class="htmlview paragraph">The author discusses the problem from three points of view: <ol class="list nostyle"> <li class="list-item"> <span class="li-label">1.</span> <div class="htmlview paragraph">The effectiveness of materials in absorbing radiation.</div></li> <li class="list-item"> <span class="li-label">2.</span> <div class="htmlview paragraph">The basic mechanisms of the interaction of radiation and matter—in order to determine the changes on the mechanical properties of materials.</div></li> <li class="list-item"> <span class="li-label">3.</span> <div class="htmlview paragraph">Radiation as a convenient and economical source of energy for irradiation of chemical systems.</div></li></ol></div><div class="htmlview paragraph">The author thinks, on the basis of the limited data available, that one of the most useful effects of radiation on matter has been the use of ionizing radiation to bring about chemical reactions, especially in organic compounds.</div></div>

<div class="htmlview paragraph">The Hybrid III family of dummies is used to estimate the response of an occupant during a crash. One recent area of interest is the response of the neck during air bag loading. The biomechanical response of the Hybrid III dummy's neck was based on inertial loading during crash events, when the dummy is restrained by a seat belt and/or seat back. Contact loading resulting from an air bag was not considered when the Hybrid III dummy was designed. This paper considers the effect of air bag loading on the 5<sup>th</sup> percentile female Hybrid III dummies. The response of the neck is presented in comparison to currently accepted biomechanical corridors.</div> <div class="htmlview paragraph">The Hybrid III dummy neck was designed with primary emphasis on appropriate flexion and extension responses using the corridors proposed by Mertz and Patrick. They formulated the mechanical performance requirements of the neck as the relationship between the moment at the occipital condyles and the rotation of the head relative to the torso. The deformation of the neck was due to the motion of the head relative to torso, when the torso was restrained either by the seat belt or the seat back. Air bag loading is significantly different from belt or seatback loading, because there is more than one load path on the head. During air bag loading, the dummy neck shows significantly different responses from those seen in the Mertz and Patrick tests. The neck experiences second mode bending during air bag loading as opposed to the first mode bending seen in seat belt and/or seat back loading.</div> <div class="htmlview paragraph">The Hybrid III 5<sup>th</sup> percentile female dummy is frequently used to estimate the response of small stature occupants to air bags. This paper examines the Hybrid III 5<sup>th</sup> percentile female dummy’s neck responses due to air bag loading. The neck responses were found to be highly dependent on how the air bag interacts with the dummy. Three modes of air bag-neck interaction were observed and studied: air bag directly loading the head, air bag trapped under the chin during the deployment process and air bag trapped behind the jaw of the dummy head. This paper also presents the results of some experimental modifications to the head/neck design of the Hybrid III 5<sup>th</sup> percentile female dummy to prevent air bag entrapment.</div>

<div class="section abstract"><div class="htmlview paragraph">Self-piercing riveting (SPR) is a key joining method in multi/thin-material automotive structures, yet accurately predicting the mechanical strength of SPR joints remains challenging due to numerous influencing factors. Empirical engineering equations [<span class="xref">1</span>] provide a foundation for estimating lap-shear and cross-tension strength but require several geometric parameters that are often unavailable in the design phase.</div><div class="htmlview paragraph">To address this limitation, we extract and leverage the core physical relationships embedded in these formulas. By reformulating the dependence of joint strength on the yield strength and total thickness of the sheet stack as practical regression models, we enable strength prediction using only commonly available material properties.</div><div class="htmlview paragraph">Furthermore, a Bayesian convolutional neural network (BCNN) model is developed to incorporate additional material features, offering improved prediction accuracy and uncertainty quantification.</div></div>