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Abstract This article analyses the flow field between two 1/8-scale Generalized European Transport System (GETS) models which are placed in a two-vehicle platoon at close distances. Numerical simulations using the lattice Boltzmann method together with a wind tunnel experiment (open jet facility, OJF) were executed. Next, to balance measurements, coaxial volumetric velocimetry (CVV) measurements were performed to obtain information about the flow field. Three intervehicle distances, 0.10, 0.45 and 0.91 times the vehicle length, were tested for various platoon configurations where the vehicles in the platoon varied in terms of front-edge radius and the addition of tails. At the smallest intervehicle distance, the greatest reductions in drag were found for both the leading and trailing vehicles. The flow in the gap between the two vehicles follows an S-shaped path with small variations between the configurations.

Abstract The paper presents a complete description of the design and manufacturing of a Carbon Fiber/epoxy mold with an embedded Carbon Fiber resistor heater, and the mold performances in terms of its surface temperature distribution and thermal deformations resulting from the heating. The mold was designed for manufacturing aileron skins from Vacuum Bag Only prepreg cured at 135°C. The glass transition temperature of the used resin-hardener system was about 175°C. To ensure homogenous temperature of the mold working surface in the course of curing, the Carbon Fiber heater was embedded in a layer of a highly heat-conductive cristobalite/epoxy composite, forming the core of the mold shell. Because the cristobalite/epoxy composite displayed much higher thermal expansion than CF/epoxy did, thermal stresses could arise due to this discrepancy in the course of heating.

Abstract This paper presents a machine learning application of the force/torque sensor in a human-robot collaborative manufacturing scenario. The purpose is to simplify the programming for physical interactions between the human operators and industrial robots in a hybrid manufacturing cell which combines several robotic applications, such as parts manipulation, assembly, sealing and painting, etc. A multiclass classifier using Light Gradient Boosting Machine (LightGBM) is first introduced in a robotic application for discriminating five different contact states w.r.t. the force/torque data. A systematic approach to train machine-learning based classifiers is presented, thus opens a door for enabling LightGBM with robotic data process. The total task time is reduced largely because force transitions can be detected on-the-fly. Experiments on an ABB force sensor and an industrial robot demonstrate the feasibility of the proposed method.

Abstract In order to improve robustness of vehicle dynamic performance, a steering mechanism model is proposed with alignment parameters of front wheel based on preference function method. In the steering mechanism model controllable variables include the trapezoid connection length, the base angle of steering trapezoid, the kingpin inclination angle, caster, camber and uncontrollable variables include load and initial braking velocity. Optimization objective is some vehicle dynamic performance. In the preference function method the individual performance preference and preference aggregation in designing variable space and performance variable space are analyzed. The individual performance preference includes the controllable variable preference, noise factor preference and optimization objective preference. The aggregation function is developed by aggregating all the individual performance preferences.

Abstract This article investigates the fuel savings potential of a series hybrid military truck using a simultaneous battery pack design and powertrain supervisory control optimization algorithm. The design optimization refers to the sizing of the lithium-ion battery pack in the hybrid configuration. The powertrain supervisory control optimization determines the most efficient way to split the power demand between the battery pack and the engine. Despite the available design and control optimization techniques, a generalized mathematical formulation and solution approach for combined design and control optimization is still missing in the literature. This article intends to fill that void by proposing a unified framework to simultaneously optimize both the battery pack size and power split control sequence. This is achieved through a combination of genetic algorithm (GA) and Pontryagin’s minimum principle (PMP) where the design parameters are integrated into the Hamiltonian function.

Abstract This study proposes a method for the rapid detection and location of cavity defects in ballastless track structures of high-speed railways in service. First, the propagation law of air-coupled ultrasonic Lamb waves in the ballastless track structure is studied. Theoretical calculation results show that the ultrasonic Lamb wave group velocity of the A2 mode in the track plate is 4000 m/s. Then, the excitation and reception methods of the air-coupled ultrasound are studied. Theoretical and experimental results show that the A2 mode Lamb wave can be generated by the 3.8° oblique incidence of the ballastless track structure. Finally, an experimental system for air-coupled ultrasonic testing is constructed. A pair of air-coupled ultrasonic probes is used to provide excitation and reception Lamb wave signals at an inclined angle of 3.8°, 20 mm away from the surface of the track plate, and 40 mm/step along the scanning direction.

Abstract To gain a better understanding of the characteristics of corrugation, including the development and propagation of corrugation, and impact of vehicle and track dynamics, a computational model was established, taking into account the nonlinearity of vehicle-track coupling. The model assumes a fixed train speed of 300 km/h and accounts for vertical interaction force components and rail wear effect. Site measurements were used to validate the numerical model. Computational results show that (1) Wheel polygonalisation corresponding to excitation frequency of 545-572 Hz was mainly attributed to track irregularity and uneven stiffness of under-rail supports, which in turn leads to vibration modes of the bogie and axle system in the frequency range of 500-600 Hz, aggregating wheel wear. (2) The peak response frequency of rail of the non-ballasted track coincides with the excitation frequency of wheel-rail coupling; the resonance results in larger wear amplitude of the rail.

Abstract The suspension system has been shown to have significant effects on vehicle performance, including handling, ride, component durability, and even energy efficiency during the design process. In this study, a new roll-plane hydraulically interconnected suspension (HIS) system is proposed to enhance both roll and lateral dynamics of a two-axle bus. The roll-plane stability analysis for the HIS system has been intensively explored in a number of studies, while only few efforts have been made for suspension tuning, especially considering lateral plane stability. This article aims to explore the integrated lateral and roll dynamics by suspension tuning of a two-axle bus equipped with HIS system. A ten-degree-of-freedom (DOF) lumped-mass vehicle model is integrated with either transient mechanical-hydraulic model for HIS or the traditional suspension components, namely, shock absorber and anti-roll bar (ARB).

"Spotlight on Design" features video interviews and case study segments, focusing on the latest technology breakthroughs. Viewers are virtually taken to labs and research centers to learn how design engineers are enhancing product performance/reliability, reducing cost, improving quality, safety or environmental impact, and achieving regulatory compliance. Just how prevalent is the problem of counterfeit electronic parts? What are the consequences of using sub-par components in safety or mission critical systems? The Federal Aviation Administration estimates that 2% of the 26 million airline parts installed each year are counterfeit, accounting for more than 520,000 units, maybe more.

The combination of internal combustion engines and electric/hydraulic motors in hybrid powertrains requires architectural and functional changes of the drive train as well as its sophisticated energy management. The 8 papers in this technical paper collection discuss the latest developments in regard to energy recuperation and storage (hydraulic, electric), power train architectures, control systems, combustion engine strategies (including exhaust emissions related aspects and certification), and vehicle application.

The 12 papers in this technical paper collection discuss technologies that address the treatment of engine exhaust emissions to meet commercial vehicle requirements. The scope covers developments in catalysis, materials, controls, and integration with the complete engine/vehicle system.

The 10 papers in this technical paper collection cover all system-level engine technologies and design/analysis/testing techniques related to engine system design. Coverage includes the areas of emissions, fuel economy, combustion, calibration/control, fuel systems, valvetrain integration, thermodynamic cycles, air/charging systems, EGR systems, and engine brakes. It also includes system-level integration issues for the engine/powertrain, and steady-state/transient performance for on/off-road and heavy/light-duty applications.

This technical paper collection features 10 papers dedicated to chassis, suspension, and tire modeling and simulation developed for and applied to vehicle systems. Topic covered include vehicle modeling, vehicle dynamic simulation analysis (handling, ride comfort, mobility, durability, etc.), and vehicle design.

Vehicle aerodynamic development, drag reduction and fuel economy, handling and stability, cooling flows, surface soiling and water management, vehicle internal environment, tyre aerodynamics and modelling, aeroacoustics, structural response to aerodynamic loading, simulating the on-road environment, onset flow turbulence, unsteady aerodynamics, fundamental flow structures, new test methods and facilities, new applications of computational fluid dynamics simulation, competition vehicle aerodynamics.

All articles of this special issue provide insight into new developments and research in energy-saving techniques in commercial vehicles, which includes advanced energy storage systems and technologies, electrified powertrain systems, novel control methods, and V2X and artificial intelligence technologies in commercial vehicles. Guest Editors: Yanjun Huang, Tongji University, China Nong Zhang, University of Technology Sydney, Australia Yuanjian Zhang, Queen’s University Belfast, UK The SAE International Journal of Commercial Vehicles publishes scientific articles on the design, modeling, controlling, and testing of commercial vehicles that bring strong empirical and theoretical contributions to the current and future body of knowledge. The articles included in this special issue comprise a wide review of research topics on recent advances in commercial vehicles and offer new approaches, control and management methods regarding energy and powertrain systems.

This technical paper collection discusses the latest developments in regard to energy management, optimization potential for combustion engine within electric/hydraulic drive trains and considers the impact on emissions, certification, and fuel consumption/CO2.

All articles in this special issue have been carefully selected to cover new developments and research on vehicle dynamics, powertrain modeling, thermal management, and cybersecurity as they relate to commercial vehicles. Special Issue Editors: Benjamin Duprey, Mechanical Simulation Corporation, USA Russell Truemner, Systems Research Engineering LLC, USA Xiaobo Yang, Oshkosh Corporation, USA The SAE International Journal of Commercial Vehicles publishes scientific articles on the design, modeling, controlling, and testing of commercial vehicles that bring strong empirical and theoretical contributions to the current and future body of knowledge. The articles in this special issue comprise a variety of articles developed from SAE International’s commercial vehicles engineering event, the Commercial Vehicle Engineering Congress (COMVEC).

This document outlines general requirements for the use of Computational Fluid Dynamics (CFD) methods for aerodynamic simulation of mass-produced cars and light-duty trucks. The document provides guidance for aerodynamic simulation with CFD methods to support current vehicle characterization, vehicle development, vehicle concept development and vehicle component development. The guidelines presented in the document include Navier-Stokes and Lattice-Boltzmann based solvers.

This document will provide recommendations to vehicle manufacturers and component suppliers in securing the SAE J1939-13 connector interface from the cybersecurity risks posed by the existence of this connector.