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Magazine
2014-06-03
Systems-engineering a new 4x4 benchmark Chrysler Powertrain teamed with AAM to create the industry's most capable, sophisticated-and arguably most fuel-efficient-AWD/4WD driveline. Top engineers talk about their collaboration. Achates aims at 2025 light-truck power After more than a decade of steady development, Achates Power's opposed-piston two-stroke diesel is impressing powertrain experts with its test results and pace of technical progress. Lighter, stronger chassis Development of a new high-strength aluminum casting alloy for the production of suspension components.
WIP Standard
2014-06-02
This SAE Recommended Practice outlines the qualification testing and performance related criteria of elastomeric boot seals used in constant velocity joint applications. These applications are referred to as front- wheel-drive halfshafts or axles, but can also be utilized in rear-wheel-drive halfshaft applications. For additional information regarding CV joint systems and their applications refer to SAE AE-7 "Universal Joint and Driveshaft Design Manual." The grease type and grease quantities, clamps and clamping mechanisms of an assembly are critical and considered to be the same as OEM, service, or aftermarket designation. Although joint lubricating grease and clamping mechanism are not addressed in this document, they are critical to a total system performance. The purpose of this document is to establish a uniform practice for those in the surface vehicle industry that specify and/or manufacture CV joint boot seals (boots) for OEM or aftermarket use with respect to qualification testing for physical and mechanical properties.
WIP Standard
2014-06-02
The following definitions and illustrations are intended to establish common nomenclature and terminology for universal joints and driveshafts used in various driveline applications. In addition, useful guidelines are included for the application of universal joints and driveshafts. For more specific details, see Universal Joint and Driveshaft Design Manual, AE-7.
Book
2014-05-21
Andrew Day
Starting from the fundamentals of brakes and braking, Braking of Road Vehicles covers car and commercial vehicle applications and developments from both a theoretical and practical standpoint. Drawing on insights from leading experts from across the automotive industry, experienced industry course leader Andrew Day has developed a new handbook for automotive engineers needing an introduction to or refresh on this complex and critical topic. With coverage broad enough to appeal to general vehicle engineers and detailed enough to inform those with specialist brake interests, Braking of Road Vehicles is a reliable, no-nonsense guide for automotive professionals working within OEMs, suppliers and legislative organizations. - Designed to meet the needs of working automotive engineers who require a comprehensive introduction to road vehicle brakes and braking systems. - Offers practical, no-nonsense coverage, beginning with the fundamentals and moving on to cover specific technologies, applications and legislative details. - Provides all the necessary information for specialists and non-specialists to keep up to date with relevant changes and advances in the area.
Technical Paper
2014-05-20
Lei Zhang
Existing multi-axle steering system designs generally use the deterministic optimization method without considering the uncertainties during the design process; therefore an actual steering movement may deviate from the ideal movement calculated by some mathematical models. In order to make design results have less sensitive to the uncertainties in the design process, some uncertainties need be taken into account at the early design stage. This paper proposes a robust optimization design method for a double front axle steering system (DFASS) of heavy trucks based on Monte Carlo method. The DFASS consists of two trapezoidal steering mechanisms (TSM) and one rocker system, and the optimization objectives of DFASS include the minimum mean value and variance of the maximum turning angle error of the TSM and rocker system. In addition, the robust optimization model includes 13 design variables which are all geometry parameters of DFASS and represented by normal distribution. Through the orthogonal experiment, we obtain the important factors affecting optimization objectives and build the response surface models of optimization objective.
Standard
2014-05-16
This SAE Recommended Practice establishes a rating scale for subjective evaluations of noise and discomfort in motor vehicles. Through test procedures utilizing specific vehicles on specific roads, the scale may be utilized to assess the relative contributions of tires to noise and discomfort. The noise and ride comfort characteristics attributed to automotive tires have traditionally been estimated by subjectively assigning number designations (commonly on a 1 to 10 scale) to the audible and tactile sensations observed while traversing a given road course in a vehicle equipped with the tires under evaluation. Regardless of advances in objective measurements of tire properties related to noise and discomfort, subjective evaluation will continue to be necessary for the purpose of establishing the significance of such measurements. The rating scale of this recommendation is applicable to assessment of each of the wide variety of audible and tactile disturbances referred to by such terms as bump, thump, slap, shake, etc.
Standard
2014-05-16
This procedure provides for the measurement of the sound generated by a test tire, mounted on a single-axle trailer, operated at multiple speeds. The procedure describes test practices for both United States and International practices. Specifications for the instrumentation, the test site, and the operation of the test apparatus are set forth to minimize the effects of extraneous sound sources and to define the basis of reported sound levels.
Standard
2014-05-16
This SAE Recommended Practice establishes a uniform procedure for a flat-road simulation of a mountain-fade test of the brake systems of light-duty trucks and multipurpose passenger vehicles up to and including 4500 kg (10 000 lb) GVW and all classes of passenger cars. The purpose of this test code is to establish brake system characteristics while simulating a mountain descent. This procedure is intended to be used to evaluate the following characteristics of a brake system: a. Brake temperature relative to fluid boil b. Fade resistance and reserve pedal travel c. Overall structural durability d. Subjective stability
WIP Standard
2014-05-13
This SAE Standard describes the performance and part requirements for elastomeric seals used in highway vehicle disc brake calipers. Seals covered by this specification may be the solid section type (square, rectangular, O-ring, etc.) mounted stationary in the cylinder bore or on the movable piston. The specification contains the following major sections:
WIP Standard
2014-05-13
This SAE Standard covers molded rubber boots used as end closures on drum-type wheel brake actuating cylinders to prevent the entrance of dirt and moisture, which could cause corrosion and otherwise impair wheel brake operation. The document includes performance tests of brake cylinder boots of both plain and insert types under specified conditions and does not include requirements relating to chemical composition, tensile strength, or elongation of the rubber compound. Further, it does not cover the strength of the adhesion of rubber to the insert material where an insert is used. The rubber material used in these boots is classified as suitable for operation in a temperature range of -40 to +120 degrees C +/-2 degrees C (-40 to +248 degrees F +/-3.6 degrees F).
Technical Paper
2014-05-10
Hyeonu Heo, Jaehyung Ju, Doo Man Kim, Harkbong Kim
An understanding of the flow around a tire in contact with the ground is important when designing fuel-efficient tires as the aerodynamic drag accounts for about one third of an entire vehicle's rolling loss. Recently, non-pneumatic tires (NPTs) have drawn attention mainly due to their low rolling resistance associated with the use of low viscoelastic materials in their construction. However, an NPT's fuel efficiency should be re-evaluated in terms of aerodynamic drag: discrete flexible spokes in an NPT may cause more aerodynamic drag, resulting in greater rolling resistance. In this study, the aerodynamic flow around a non-pneumatic tire in contact with the ground is investigated for i) stationary and ii) rotating cases using the steady state Reynolds-Averaged Navier-Stokes (RANS) method. A sensitivity analysis was carried out with a varying mesh density. The flow into cavity by the discrete spoke geometry of the NPT does not significantly affect the overall aerodynamic drag.
Technical Paper
2014-05-10
Daogao Wei, Peng Wang, Zhijie Pan, Siming Hu, Huaiyang Xiao
Tie rod end clearance is an important parameter influencing automobile stability under slalom maneuver. In this paper the steering mechanism is simplified into a plane linkage mechanism and an analysis of the effects on vehicle stability exerted by kinematic pair clearance under slalom maneuver is also presented. A 4DOF mathematical model of vehicle maneuvering system is thus being built. On the basis of this model, we adopt the numerical analysis method to conduct a simulated analysis about the stability of prototype vehicle side slip angle as the clearance parameter changes. According to the results, vehicle slalom dynamics behaviors manifest itself in shifting from single cycle to chaos directly. With the increase in clearance, nearly no change is displayed in the upper critical frequency of vehicle slalom instability. However, an increasing rise is shown in the lower critical frequency. The instability frequency bandwidth, accordingly, bears an increase as well and a marked difference manifests itself with regard to the characteristics of window dynamics in chaotic areas.
Technical Paper
2014-05-07
Eraldo de Jesus Soares, Alan M. Oliva, Camilo A. Adas, Fernando C. Dusi, Paulo Sergio P. Santos, Marco A. Fogaça Accurso, Marcus Kliewer
Abstract The purpose of this paper is to show a multiaxial bench test for static and dynamic testing of leaf springs for suspension of commercial vehicles. The bench test simulates the critical operating conditions (track, ramp, speed bump on track, curves and braking), with stroke control for strength and deformation analysis. One of the main advantages in bench test is to reduce the time of the test, its repeatability, its cost saving and monitoring its performance through inspections and graphic records. The aim of the test is to evaluate the behavior in durability of the components, to analyze the possible failure mode and to be able to approve or reject the component based on the test's results. Criteria were set to accelerate the test by comparing signals measured on the field and bench test with deflection by stress curves. These criteria were maintained under extreme conditions for longer than the observed in previous and real applications. With this, the low incidence of strength and stroke is measured by optimizing the time of the test.
Technical Paper
2014-05-07
Claudio Gomes Fernandes, Eric Noguchi, Rômulo Castro, Uilian Almeida
Abstract Automotive industry has shown, in the recent years, a dramatically increase of competition at emergent markets. The incoming of new Brands, for example in the Brazilian market, is causing the OEMs to decrease costs while increase quality, which represents a big challenge nowadays. In this challenging scenario, virtual simulation has become mandatory. While cutting costs since no physical prototypes are required, virtual models also reduces development time. Time to time, as computers processing capacity grows, virtual models are becoming more and more accurate, being able to capture even high non-linear phenomena, which ten years ago would not be feasible. It is also known the natural tendency of vehicle dynamics engineers to develop shock absorber tuning only by means of subjective evaluation. Many reasons can be raised to this tendency, but one of them is the lack of representation of the entire shock absorber behavior in the virtual models. In this sense, the present work shows an attempt to capture the main non-linearities of shock absorbers that affect the most the vehicle behavior in terms of ride and handling.
Technical Paper
2014-05-07
Frederico A. A. Barbieri, Vinicius de Almeida Lima, Leandro Garbin, Joel Boaretto
Abstract Brazil presents a very diverse road and traffic conditions and due to several factors the number of truck accidents is very high. Inside truck accidents group, the one that causes the highest number of losses and fatalities is the rollover crash and understanding rollover dynamics is very important to prevent such events. The diversity of cargo vehicles arrangements requires a detailed study regarding the dynamic behavior these vehicle combinations in order to increase operation safety. The same tractor unit can be used with different types and numbers of trailers and/or semi-trailers, each one with different suspension configurations. These truck combinations have distinct dynamic performances that need evaluation. In this sense, this work presents a first phase study on the dynamic behavior of different types of cargo vehicle configuration. A 6×2 tractor is combined with a two distinct grain semi-trailer with different types of suspension: pneumatic and leaf spring. The study is conducted in order to verify the difference in dynamic behavior and the resulting stability of the two configurations in different conditions of speed and maneuvers.
Technical Paper
2014-05-07
Marcos dos Santos, Ricardo Guedes Manini, Jayme B. Curi, Cleber Chiqueti
Abstract ”U” bolts are fixing elements and they are used to clamp an elastic joint. From the past, they still looking as an old design and unfortunately, suspension engineers are not specialists in fasteners and elastic joints. That is why we will show important assumptions and concepts to design and specifications this clamp element “U” bolt and its influence over leaf-springs. Currently, “U” bolt is used to clamp an elastic or elastic-plastic joint of heavy duty suspension, formed by leaf-spring, axle, spring pad, “U” bolt plate. This kind of suspension is typically used to trucks, buses and trailers. We are wondering, which one important assumption that an engineer must be careful when designs a new suspension changing from old designs to an updated technology. We provide a theoretical analysis and a FEA analysis to compare torque efficacy x leaf-spring reactions and what are effects this relationship can cause in a suspension. To have a shortest development time and provide back an expected result from the suspension system, engineers should to consider more and new assumptions, evaluate virtual and practical performance of leaf-springs with “U” bolt designed to clamp all elastic joint and even the correct torque specification to the “U” bolt.
Technical Paper
2014-05-07
Alfred Memmel, Anibal Berberich
Abstract Variable Damping systems for commercial vehicle applications have been in the market for several years now. The systems modify damping according to the actual demand within milliseconds. This reduces vertical accelerations which lead to improved comfort while maintaining vehicle stability and safety at the same time. Driver, cargo and vehicle are better protected. The technical effort for variable damping systems was in the past rather high and affected a limited market penetration. On the other side the used control algorithms did not tap the full potential of the system performance. New concepts, like integration of sensors or concentration on the most relevant axle, in combination with new control algorithms, simplifies the systems architecture and improves the performance. Besides the functional advantages, the system improves vehicle efficiency as it reduces the energy dissipated by the dampers. This energy would have to be generated by the engine. Less damping also relates to reduction of fuel consumption.
Technical Paper
2014-05-07
Saulo Machado Rodrigues, André Soares, Henrique Zambon, Odair Berti, Rudimar Mazzochi
During the field tests of a prototype of a cabin suspension assembly applied in a commercial vehicle it has been evidenced the premature failure in the torsion bar. Due to this failure, which happened with 20% of approval total test, one verified that the adding of a lateral displacement control bar (Panhard), attached to the torsion bar, promoted a significant additional force to it, which was not predicted in the initial dimensioning. Due to that, it was executed a re-design of the assembly, paying a special attention to the torsion bar, considering the influence of Panhard bar. To do that, several numerical simulations were carried out, using the finite element software Abaqus, whose boundary conditions were determined based on data collected in the field tests. Lately, the new concepts developed were submitted to bench tests, applying hydraulic actuators to apply the loads, in which one executed an experimental verification of stresses to calibrate the numerical models.
Technical Paper
2014-05-07
Fabio Augusto Schuh, Leandro Luís Corso, Leonardo Hoss
Abstract Applying knowledge available at technical literature for cycle counting, damage caused by each load cycle through S-N curve, and fatigue damage accumulation by Palmgren-Miner rule, durability prediction is performed for a leafspring of a commercial vehicle with 6×4 suspension system. Max principal tension is measured by means of strain gages in the most representative points for fatigue life of the leafspring, determined with FEA, while vehicle runs over off-road track in a proving ground. Load and tension are also measured in a laboratory bench test for this component. Correlation between off-road track and bench test is then performed. Finally, representative samples of the component are tested with dynamic loading until fatigue fracture in bench test, and using data from these tests, statistical analysis is performed with application of Weibull distribution, allowing life prediction in statistical terms.
Standard
2014-05-07
These performance requirements have been established for manual slack adjusters when tested to SAE J1461. To establish acceptable levels of performance for manual slack adjusters.
Article
2014-04-29
Despite the burgeoning success of highly effective single platform modular solutions, hardware variation is not falling, warns BWI Group global technology executive Olivier Raynauld.
WIP Standard
2014-04-29
This SAE Aerospace Standard (AS) sets forth criteria for the selection and verification processes to be followed in providing tires that will be suitable for intended use on civil aircraft. This document encompasses new and requalified radial and bias aircraft tires.

This document establishes the minimum recommended performance standards for new tires to be used on civil aircraft. All new or requalified tires shall meet these standards.

Technical Paper
2014-04-28
Rohitt Ravi, Sivasubramanian, Bade Simhachalam, Dhanooj Balakrishnan, Krishna Srinivas
Abstract Tubular stabilizer bar for commercial vehicle is developed using advanced high strength steel material. Tubular section is proposed to replace the existing solid section. The tubular design is validated by component simulation using ANSYS Software. The tubes are then manufactured of the required size. The bend tool is designed to suit the size of the profile stabilizer bar and the prototypes are made using the tube bending machine. The strength of the tubular stabilizer is increased by using robotic induction hardening system. The tubular stabilizer bar is tested for fatigue load using Instron actuators. Higher weight reduction is achieved by replacing the existing solid stabilizer bar with the tubular stabilizer bar.
Technical Paper
2014-04-28
Ashok KK, Bade Simhachalam, Dhanooj Balakrishnan, Krishna Srinivas
Abstract In this paper, the application of tube Extrusion for the development of stepped tubular components is discussed. Thickness increase with respect to cold reduction of diameter is predicted with reasonable accuracy. Thickness increase, length increase and strain hardening coefficient for a given cold reduction of diameter of tube are obtained using LS-DYNA Software. True stress-plastic strain curves from the tensile test are used in the forming simulation using LS-DYNA. A special purpose machine is developed for the production of steering shaft components. Considerable reduction in weight is achieved by using stepped tubular components.
Technical Paper
2014-04-28
Y. S. Thipse
Abstract Hyperelastic material simulations are commonly performed in commercial FE codes due to availability of sophisticated algorithms facilitating virtual characterization of such materials in FEA easily. However, the solution time required is longer in FEA. Especially when excitation frequencies do not interfere with structural modes, flexible multibody simulation offers a lucrative and computationally inexpensive alternative. However, it is difficult to directly characterize hyperelastic materials in commercial MBS simulation codes, so the reduced solution time comes at the cost of decreased simulation accuracy, especially if the designer is provided with crude stress - strain test data. Hence, the need is to overcome the drawbacks in FEA and multibody codes, as well as to leverage best of both these codes simultaneously. A methodology is presented where non-linear stiffness properties of the hyperelastic materials are expressed as an analytical function in terms of constants of hyperelastic constitutive material models.
Technical Paper
2014-04-28
Shital M. Kalikate, Satyajit R. Patil, Suresh M. Sawant
Abstract Magneto-rheological (MR) fluid is a type of smart material which has ability to change its flow resistance on the application of magnetic field. This property of changing viscosity of the fluid due to application of magnetic field is utilized in the MR brake. MR brake typically consists of multiple rotating disks immersed in MR fluid and an enclosed electromagnet. The controllable yield stress produces shear friction on the rotating disks, generating the braking torque. Of late MR brakes have been explored for automotive applications. Literature review reveals that the torque output of MR brake is not sufficient for braking of mid-sized car. Hence, it is worthwhile to investigate its application for a two-wheeler where the braking torque requirement is low. This paper presents design and simulation of MR brake performance for its torque output. Design of MR brake involves deciding the configuration of MR brake in terms of number and sizing of disks, selection of MR fluid and design of magnetic circuit.
Standard
2014-04-28
This SAE Recommended Practice is intended for testing of manual slack adjusters as they are used in service, emergency, or parking brake systems for vehicles that can be licensed for on-road use. Purpose This document establishes an accelerated laboratory test procedure for manual slack adjusters to determine their integrity and durability in various functional modes and environmental conditions.
WIP Standard
2014-04-21
This SAE Recommended Practice was prepared by the Motor Vehicle Brake Fluids Subcommittee of the SAE Hydraulic Brake Systems Actuating Committee to provide engineers, designers, and manufacturers of motor vehicles with a set of minimum performance standards in order to assess the suitability of silicone and other low water tolerant type brake fluids (LWTF) for use in motor vehicle brake systems. These fluids are designed for use in braking systems fitted with rubber cups and seals made from natural rubber (NR), styrene-butadiene rubber (SBR), or a terpolymer of ethylene, propylene, and a diene (EPDM). In the development of the recommended requirements and test procedures contained herein, it is concluded that the LWTFs must be functionally compatible with existing motor vehicle brake fluids conforming to SAE J1703 and with braking systems designed for such fluids. To utilize LWTFs to the fullest advantage, they should not be mixed with other brake fluids. Inadvertent mixtures of LWTFs with fluids meeting SAE J 1703 are not known to have any adverse effects on performance, but all combinations have not been tested.
Standard
2014-04-16
This SAE Information provides information applicable to production Original Equipment Manufacturer antilock braking systems found on some past and current passenger cars and light trucks. It is intended for readers with a technical background. It does not include information about aftermarket devices or future antilock brake systems. Information in this document reflects that which was available to the committee at the time of publication.
Book
2014-04-11
Today’s designers seek to integrate sensor technology, electronic and mechatronic systems in progressively introducing Electric Power Steering (EPS) systems. However, from a customer perspective on the one hand steering is one of the most visible or tangible aspects of vehicle quality in driving when quality is compromised (through NVH issues), while on the other hand, when executed well, a steering system is all but transparent to the driver. To a number of commentators and OEMs ‘steering feel’ has become termed as contributing to the essential ‘DNA” of the vehicle, and it is therefore an essential aspect of competitive advantage or position. This report examines steering feel and the increasing effect of vehicle electrification, and looks at steering and chassis performance. It also considers the key drivers including fuel efficiency and CO2 emissions, steering design, materials considerations and the packaging dilemma. Furthermore the report looks at the latest steering system trends, in particular electrically power assisted steering (EPAS), electro-hydraulic power steering (EHPS), electric power steering (EPS), active front steering (AFS), four-wheel steering, steer-by-wire, automated parking and NVH reduction.
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