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Technical Paper

A Statistical Method to Substructure Crash Simulation Model

2021-12-03
2021-01-5107
This work presents a statistical method to use a portion of a full finite element vehicle model on a crash analysis event. The substructure model is linked to the full model by recording the interface boundary history. The lateral moving deformable barrier (MDB) test by the Insurance Institute for Highway Safety (IIHS) is used to demonstrate this substructure method: Substructure portion is identified by energy absorption distribution, and noise elements are filtered out by density-based spatial clustering of applications with noise (DBSCAN), a nonsupervised machine learning method. Crashworthiness simulation is performed in LS-DYNA software, and results between substructure vehicle model, full vehicle model, and physical vehicle test results are compared. It shows the result from the substructure model is more effective without accuracy compromise.
Technical Paper

Grid Independence Validation and Numerical Simulation of an Opposed-Piston Free-Piston Engine

2021-11-23
2021-01-5104
To evaluate the grid independence of the in-cylinder numerical simulation, the combustion chamber model of an opposed-piston free-piston engine was divided into three styles: structured, unstructured, and hybrid meshes. Furthermore, the grid independence of the hybrid mesh was analyzed using different grid resolutions. In order to avoid the influence of subjective judgments, the grid resolution is introduced to characterize the degree of grid refinement, combined with the grid convergence index (GCI) to assess the convergence of simulation. The results show that there are differences in the flow fields for the different grid styles. In addition, the hybrid mesh captured more small-scale swirls around the intake and exhaust ports. When the resolution reached 12, the GCI was less than 6%, indicating that the numerical simulation was impervious to the grid resolution. Moreover, the mixing distribution hardly changed when the resolution reached 12.
Research Report

Unsettled Issues Concerning Urban Air Mobility Infrastructure

2021-11-15
EPR2021025
Urban air mobility (UAM) refers to urban transportation systems that move people by air. UAM offers the potential for reducing traffic congestion in cities and providing an integrated approach to urban mobility. With the emergence of electric vertical takeoff and landing (eVTOL) aircraft, drone technology, and the possibility of automated aircraft, interest in this topic has grown considerably for private sector solution providers—including aerospace and technology companies—as well as urban planners and transportation professionals. Unsettled Issues Concerning Urban Air Mobility Infrastructure discusses the infrastructure requirements to effectively integrate UAM services into the overarching urban transportation system to enable multimodal trips and complete origin to destination travel. Click here to access the full SAE EDGETM Research Report portfolio.
Research Report

Unsettled Aspects of the Digital Thread in Additive Manufacturing

2021-11-15
EPR2021026
Additive manufacturing (AM), also known as “3D printing,” now provides the ability to have an almost fully digital chain from part design through manufacture and service. This “digital thread” can bring great benefits in improving designs, processes, materials, operations, and the ability to predict failure in a way that maximizes safety and minimizes cost and downtime. Unsettled Aspects of the Digital Thread in Additive Manufacturing discusses what the interplay between AM and a digital thread in the mobility industry would look like, the potential benefits and costs, the hurdles that need to be overcome for the combination to be useful, and how an organization can answer these questions to scope and benefit from the combination. Click here to access the full SAE EDGETM Research Report portfolio.
Research Report

Unsettled Issues in Commercial Vehicle Platooning

2021-11-15
EPR2021027
While platooning has the potential to reduce energy consumption of commercial vehicles while improving safety, both advantages are currently difficult to quantify due to insufficient data and the wide range of variables affecting models. Platooning will significantly reduce the use of energy when compared to trucks driven alone, or at a safe distance for a driver without any automated assistance. However, drivers typically drive closer to each other than recommended to achieve drafting efficiencies, which may shift the benefit of automated platooning to safety gains. More data will be needed to conclusively demonstrate these gains. Unsettled Issues in Commercial Vehicle Platooning discusses the technologies needed to enable close platooning, including brake system condition monitoring, vehicle-to-vehicle communication, and concrete infrastructure assessment. The report also looks at driver acceptance of platooning technology from a safety and job security perspective.
Technical Paper

Measurement Methods for Radar Cross Section of Passenger Vehicles

2021-11-09
2021-01-5103
Automotive millimeter-wave radar is used extensively in vehicle active safety. The Radar Cross Section (RCS) is one of the main parameters used by the automotive radar system to detect and identify surrounding vehicles. The RCS describes the electromagnetic scattering properties of objects. This paper describes a method and equipment to measure the RCS. An automobile-grade radar is used to measure the RCS of typical vehicles. A representative distance between the radar and the vehicle was chosen based on the analysis of the RCS of passenger vehicles in different distances in the near field. A cost-effective rotating platform was developed to rotate the passenger vehicles for RCS measurement in different azimuth angles. The RCS generated by the rotating platform was analyzed and mitigated. The measurement system can record the synchronized azimuth angle and RCS measurement.
Technical Paper

Four Common Deficiencies in the Current Thermodynamics of Internal Combustion Engines

2021-11-05
2021-01-5098
This paper redraws and shows the pressure volume Pv- diagram and the T-S diagram of the Carnot cycle, Otto engine, and turbocharged Zhou Engine. It imitates the thermodynamic analysis of steam or gas turbines, takes into account the transport-work, and rederives the ideal thermal efficiency formula of Otto engines, which is much different from the current one. It is found that the current thermodynamics of internal combustion (IC) engines neglected the transport-work and the entropy increase in the exhaust pipe, overvalued the ideal thermal efficiency, and is a wrong line in the temperature entropy (T-S) diagram. In particular, the entropy increase in the exhaust pipe hides and wastes a lot of mechanical energy, which the turbocharged Zhou Engine can recycle.
Technical Paper

Electrician Demand for Battery Electric Vehicle Charger Installation

2021-11-03
2021-01-5102
Demand for electricians was estimated based on projected increases in battery electric vehicle (BEV) sales. Total BEV sales were projected from current producer plans. Each scenario for charger type and charging location requires different combinations of electrical installation requirements. The need for types of charging will vary by location and individual preferences. Interviews with practicing electricians and field surveys were performed to assess current capabilities and the need for improvements. Very few current vehicle owners are prepared to make a smooth transition to even level 1 charging. It was determined that the demand for licensed electricians will increase by 25% over 20 years solely for the purpose of charger installation. However, this profession has been dropping over time and is under demand for growth from other areas such as green power.
Technical Paper

Dissecting Robust Resource Partitioning, Robust Time Partitioning, and Robust Partitioning in CAST-32A

2021-11-03
2021-01-5101
CAST-32A strategy for MCP certification builds upon the key terms of robust resource partitioning, robust timing partitioning, and robust partitioning. In this work, we provide technical insight on the interpretation of these terms by building on derivative terms such as resource capacity, capacity allocation, and capacity verification and violation. We discuss on the scope of applicability of these terms from the low-level hardware components up to the complete MCP platform. We also dig into the complexities in implementing robust resource and time partitioning, and show that those concepts must be applied bottom-up from hardware-shared resources up to the whole platform. We also show that, while robust resource partitioning is the preferred choice, it can only be realistically applied to some resources and, in many cases, robust time partitioning is the only choice.
Technical Paper

Seat Belts: A Review of Technological Milestones, Regulatory Advancements, and Anticipated Future Trajectories

2021-10-21
2021-01-5097
Decades after their introduction, seat belts remain the most important safety innovation in automotive history. Seat belt usage remains the single most effective way to minimize the risk of injury or death in severe crash events. Despite having matured, seat belts continue to evolve and improve and are expected to play an equally critical role in future passenger vehicles as increasing automation leads to changes in occupant compartment design and occupant-to-vehicle interaction. In this paper, an overview of major technical milestones in the development of seat belts is presented, ranging from the earliest lap belts to today’s systems that seamlessly synthesize and integrate information from a variety of sensors to prepare the restraints for an imminent crash. A brief overview of contemporary regulatory events is also provided, illustrating how regulatory actions have followed and occasionally driven the development and proliferation of various aspects of occupant restraints.
Research Report

Unsettled Issues Regarding First- and Last-mile Transport

2021-10-15
EPR2021024
Sustainable first/last/only-mile (FLO-mile) transport is the key to sustainable travel. It could directly replace private car use for short urban journeys, which account for 1% of global greenhouse gas emissions. More importantly, it could enable public transport to be used for longer journeys, which account for 6% of emissions. Active travel, such as walking and cycling, has the lowest emissions and provides huge economic benefits that pay for the required infrastructure many times over. Unsettled Issues Regarding First- and Last-Mile Transport discusses the mass switch to more sustainable modes of transport and how to increase their perceived value to users. It also covers the prioritization of publicly owned cycles over rideshare options due to the latter’s higher lifecycle emissions, including manufacture, redistribution, and service operations and station construction. Click here to access the full SAE EDGETM Research Report portfolio.
Technical Paper

The Behavior of Fuel Droplets on a Heated Substrate

2021-10-15
2021-01-5099
The processes of surface wetting and film evaporation play a major role in any application using liquid fuels. Since the behavior of entire multi-liquid films is influenced by many simultaneously occurring physical processes, exact modeling is not yet possible. In order to reduce the complexity and to determine the basic effects in the spreading and evaporation of multi-component films, this study was carried out by placing single 5 μl droplets on a heated metal surface. Various alkanes, ethanol, and mixtures, as well as real gasoline, were studied at surface temperatures between 69°C and 140°C. To describe the processes qualitatively and determine the time-dependent wetted surface area, the droplets were visualized using cameras. With the results, it was possible to determine the course of the wetted surface over time and to compare different liquids under varying surface temperatures.
Research Report

Unsettled Economic, Environmental, and Health Issues of Ammonia for Automotive Applications

2021-10-15
EPR2021022
Ammonia has been previously trialed as an automotive fuel; however, it was hardly competitive with fossil fuels in terms of cost, energy density, and practicality. However, due to climate change, those practical and cost-related parameters have finally become secondary deciding factors in fuel selection. Ammonia is safer than most fuels and it offers superior energy densities compared to compressed or liquefied hydrogen. It is believed that ammonia might be an ultimate clean fuel choice and an extension to the emerging hydrogen economy. Unsettled Economic, Environmental, and Health Issues of Ammonia for Automotive Applications examines the major unsettled issues of using ammonia as a clean automotive fuel alternative, including the lack of regulations and standards for automotive applications, technology readiness, safety perception, and presently limited supply.
Research Report

Unsettled Aspects of Insourcing and Outsourcing Additive Manufacturing

2021-10-15
EPR2021023
Additive manufacturing (AM), also known as “3D printing,” has transitioned from concepts and prototypes to part-for-part substitution—and now to the creation of part geometries that can only be made using AM. As a wide range of mobility OEMs begin to introduce AM parts into their products, the question between insourcing and outsourcing the manufacturing of AM parts has surfaced. Just like parts made using other technologies, AM parts can require significant post-processing operations. Therefore, as AM supply chains begin to develop, the sourcing of AM part building and their post-processing becomes an unsettled and important issue. Unsettled Aspects of Insourcing and Outsourcing Additive Manufacturing discusses the approaches and trade-offs of the different sourcing options for production hardware for multiple scenarios, including both metallic and polymer technologies and components. Click here to access the full SAE EDGETM Research Report portfolio.
Technical Paper

Application of Combined Electric Arc Coatings for Parts and Units of Vehicles Recovery in Repair Technologies

2021-10-15
2021-01-5100
This paper is devoted to the methods of increasing wear resistance, corrosion resistance, and service life of parts and assemblies of vehicles during their strengthening and renovation by the use of combined electric arc spraying (EAS) coatings. High density, adhesion, and microhardness of EAS coatings are provided by activation of the spraying process and subsequent nitriding of the sprayed coatings. This study is about the influence of technological parameters of the spraying process—composition, diameter and feed rate of sprayed wires, arc power, spray gas flow rate, spraying distance, speed of spraying spot movement, dispersion of spraying, etc.—on the qualitative characteristics of EAS coatings. The possibility of using pulsed ion nitriding (PIN) to improve the operational characteristics of EAS coatings made of wire materials is considered.
Technical Paper

Lining Property Characterizations for an Improved Integration Cascade

2021-10-11
2021-01-1272
New technologies, such as electrified powertrain and autonomous driving solutions, are transforming the automotive industry in such a way that achieving vehicle level performance requirements demands an increasingly intensive and detailed system integration exercise. Validation of the braking system, critical to any vehicle level project, must evolve so that the ever-increasing requirements cascade is answered in a way that ensures the highest level of safety and performance as the industry moves toward a new frontier of features. To support this evolution of integration methodology, critical-to-performance components, such as brake pads, must undergo a transformation in how performance metrics are characterized, communicated, and documented.
Technical Paper

Lining Wear Measurements using a Coordinate Measurement Machine

2021-10-11
2021-01-1270
Accurate measurements of brake friction materials are critical to understanding brake behaviors during testing. Current methods typically utilize a hand gauge (or a machine, in some cases) to sample various discrete points on the brake lining. This approach limits measurements to planar wear characteristics, taper and thickness, and excludes more complex measurements such as cupping. The limited number of points means that a single errant point measurement or the choice of point locations can have a large impact on the reported wear measurement. This paper will describe a method for utilizing a Coordinate Measurement Machine (CMM) fitted with a laser line scanning tool to generate a point cloud of data that can then be compared to an earlier measurement of the same piece or to a math model. This method produces thousands of data points which allows for more accurate volumetric wear calculations and color maps of the entire friction face.
Technical Paper

Designing a Next Generation Trailer Braking System

2021-10-11
2021-01-1268
Passenger vehicles have made astounding technological leaps in recent years. Unfortunately, little of that progress has trickled down to other segments of the transportation industry leaving opportunities for massive gains in safety and performance. In particular, the electric drum brakes on most consumer trailers differ little from those on trailers over 70 years ago. Careful examination of current production passenger vehicle hardware and trailering provided the opportunity to produce a design and test vehicle for a plausible, practical, and performant trailer braking system for the future. This study equips the trailer with high control frequency antilock braking and dynamic torque distribution through use of passenger vehicle grade apply hardware.
Technical Paper

Research on Locked Wheel Protection Function of Aircraft Brake System

2021-10-11
2021-01-1269
Locked wheel protection is an important part of antiskid control for aircraft brake control system. Locked wheel protection compares the wheel speed of two or more wheels, if one of the wheels is too slow, locked wheel protection releases the brake pressure on the slow wheel. This work aims to study the control logic for locked wheel protection. Locked wheel protection control logic consists of 3 key factors: paired wheels, active threshold and inhibit velocity. Focus on comparison different options of these 3 factors, all aspects of control logic for locked wheel protection had been expounded in this study. Simulation and calculation analysis is applied for different locked wheel strategies to evaluate the effect. One conclusion is that the greatest wheel speed of the wheel under control shall be set as a reference speed for locked wheel protection. This study provide the basis to design a proper locked wheel protection function of aircraft brake control system.
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