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2015-07-01
Journal Article
2015-01-9112
Shahyar Taheri, Terence Wei
Modeling the tire forces and moments (F&M) generation, during combined slip maneuvers, which involves cornering and braking/driving at the same time, is essential for the predictive vehicle performance analysis. In this study, a new semi-empirical method is introduced to estimate the tire combined slip F&M characteristics based on flat belt testing machine measurement data. This model is intended to be used in the virtual tire design optimization process. Therefore, it should include high accuracy, ease of parameterization, and fast computational time. Regression is used to convert measured F&M into pure slip multi-dimensional interpolant functions modified by weighting functions. Accurate combined slip F&M predictions are created by modifying pure slip F&M with empirically determined shape functions. Transient effects are reproduced using standard relaxation length equations. The model calculates F&M at the center of the contact patch.
2015-06-30
Article
Off-highway machine mounting systems, especially the cab mounting system, significantly affect the operator comfort in the cab by providing enough damping for a good ride and isolating the structure-borne forces from traveling into the cab.
2015-06-30
Standard
J1808_201506
This document applies to direct acting vacuum power assist brake boosters only, exclusive of the master cylinder or other brake system prime mover devices for passenger cars and light trucks [4500 kg GVW (10 000 lb)]. It specifies the test procedure to determine minimum performance and durability characteristics.
2015-06-29
WIP Standard
J1555
This SAE Recommended Practice applies to all portions of the vehicle, but design efforts should focus on components and systems with the highest contribution to the overall average repair cost (see 3.7). The costs to be minimized include not only insurance premiums, but also out-of-pocket costs incurred by the owner. Damageability, repairability, serviceability and diagnostics are inter-related. Some repairability, serviceability and diagnostics operations may be required for collision or comprehensive loss-related causes only, some operations for non-collision-related causes only (warranty, scheduled maintenance, non-scheduled maintenance, etc.), and some for both causes. The scope of this document deals with only those operations that involve collision and comprehensive insurance loss repairs.
2015-06-22
WIP Standard
J1939DA
This document is intended to supplement the J1939 documents by offering the J1939 information in a form that can be sorted and search for easier use. The J1939 Digital Annex, introduced in August 2013, offers key J1939 technical data in an Electronic Spreadsheet that can be easily searched, sorted, and adapted to other formats. J1939DA contains all of the SPNs (parameters), PGNs (messages), and other J1939 data previously published in the SAE J1939 top level document. J1939DA also contains all of the SLOTs, Manufacturer ID Codes, NAME Functions, and Preferred Addresses previously published in the SAE J1939 top level and the J1939-71 document. J1939DA contains the complete technical details for all of the SPNs and PGNs previously published in the SAE J1939-71 document. It also includes the supporting descriptions and figures previously published in the SAE J1939-71 document.
2015-06-15
Journal Article
2015-01-2355
Luke Fredette, Jason Dreyer, Rajendra Singh
Abstract Hydraulic bushings with amplitude sensitive and spectrally varying properties are commonly used in automotive suspension. However, scientific investigation of their dynamic properties has been mostly limited to linear system based theory, which cannot capture the significant amplitude dependence exhibited by the devices. This paper extends prior literature by introducing a nonlinear fluid compliance term for reduced-order bushing models. Quasi-linear models developed from step sine tests on an elastomeric test machine can predict amplitude dependence trends, but offer limited insight into the physics of the system. A bench experiment focusing on the compliance parameter isolated from other system properties yields additional understanding and a more precise characterization.
2015-06-15
Technical Paper
2015-01-2351
Hongyu Shu, Shuang Luo, Li Wang
Abstract In order to measure the noise of auto shock absorbers, a test bench used to detect piston-rod vibration responses of shock absorbers and measuring analyzer named SANTS-I were developed. The vibration response data was detected by bench tests, which shows that there are high-frequency violent peaks on the sine curve of piston-rod oscillating with relative low frequency. In order to explain the interior work dynamic mechanism of shock absorbers, a schematic Micro-process Dynamic Model with 10 steps particularly divided extension and compression stroke in more detail, and dynamic differential equations for each step were presented and discussed. Furthermore, numerical simulation for the inner impacts interaction between piston and damping fluid of hydraulic shock absorber was realized by ADINA software, by the establishment of a gas-liquid two-phase finite element model.
2015-06-15
Technical Paper
2015-01-2353
Jan Bunthoff, Frank Gauterin, Christoph Boehm
Abstract In an automotive suspension, the shock absorber plays a significant role to enable the vehicle performances, especially in ride, handling and Noise-Vibration-Harshness (NVH). Understanding its physical characteristics is of great importance, as it has a main influence on the overall vehicle performance. Within this research project simulation models for different passive monotube shock absorber systems have been created in a 1-D system simulation software. The simulation models are designed and parameterized physically. To validate the simulation models measurements on different hydropulse-shaker with specially designed control signals to investigate the response during high frequency excitation, have been done. A detailed discussion of the several models and results of a simulation to measurement comparison is given. After detailed investigation the shock absorber simulation models are now adaptable to the multi body simulation.
2015-06-15
Journal Article
2015-01-2193
Masami Matsubara, Daiki Tajiri, Makoto Horiuchi, Shozo Kawamura
Abstract One of the elements of tire stiffness is sidewall stiffness. This stiffness, which influences tire vibration characteristics, is also an important design parameter for carrying the vehicle body. Tire is one of pressure vessels and inflation pressure is dominant in sidewall stiffness. Thus, tire sidewall stiffness is decided from the tension of inflation pressure and the structural dynamic, including the properties of the rubber material. To reveal the dynamic characteristics of tire sidewall stiffness, this study describes differences in stiffness due to inflation pressure. It can be expected that variation of inflation pressure is monitored from the axle vibration response during vehicle traveling in the future. That is because the relationship of the vibration characteristics and the inflation pressure of tire are derived by sidewall stiffness. First, we derive a formula for sidewall stiffness based on the structural dynamics of Akasaka's theory.
2015-06-15
Technical Paper
2015-01-2194
Giorgio Bartolozzi, Marco Danti, Guido Nierop, Andrea Camia
Abstract Within the automotive industry, a typical way to account for tires in a roadnoise mission simulation is to use the “modal model” supplied by tire manufacturers. Even though this kind of models is certified by the suppliers and is very simple to use, it has the drawback to be disconnected from the physical description of the tire. This reflects in limiting the carmaker company to be able only to request certain modal characteristics to the supplier. The aim of this paper is to present an accurate, yet easy to use, methodology to develop an FE model of a tire, to be used in a full-vehicle simulation. The determined model must be connected to the tire physical properties. These properties are not measured directly, but determined by tuning a properly created geometric FE model to the measured point inertances of the inflated tire. This allows creating the model only by using an optimization algorithm to tune such properties.
2015-06-15
Journal Article
2015-01-2196
Farokh Kavarana, Scott Fritz, John DeYoung
Abstract Recent trends in vehicle light-weighting and tire design requirements have created an increased awareness to tire flat-spotting. Tire flat-spotting occurs when tires remain in a loaded condition without rolling for an extended period of time. Tire flat-spotting can either be temporary or permanent depending on the length of storage and other environmental factors. Tire non-uniformity caused due to flat-spots often induces shake and shimmy (back and forth oscillation of steering wheel) vibration in vehicles due to increased tire-wheel force variation input into the chassis. This can result in increased warranty costs for OEMs (Original Equipment Manufacturers) as well as customer dissatisfaction exhibited in third party quality surveys like the annual J. D. Power IQS (Initial Quality Survey).
2015-06-15
Technical Paper
2015-01-2198
Masami Matsubara, Nobutaka Tsujiuchi, Takayuki Koizumi, Akihito Ito, Kensuke Bito
Abstract Early studies on the tire vibration characteristics of road noise focused on radial modes of vibration because these modes are dominant in vertical spindle force. However, recent studies of Noise, Vibration and Harshness (NVH) prediction have suggested that tire modeling not only of radial modes, but also of lateral vibration, including lateral translational and lateral bending modes, affect interior noise. Thus, it is important to construct tire dynamic models with few degrees of freedom for whole-vehicle analysis of NVH performance. Existing tire dynamics model can't express tire lateral vibrations. This paper presents a new approach for tire vibration analysis below 200Hz, and a formula for tire natural frequencies. First, a tire dynamic model is developed based on the thin cylindrical shell theory. Kinetic and potential energies are derived. Mode shape function is also derived by the assumption of inextensility in the neutral of the tread ring.
2015-06-15
Journal Article
2015-01-2199
Rui Cao, J Stuart Bolton
Abstract Experimental measurements of tire tread band vibration have provided direct evidence that higher order structural-acoustic modes exist in tires, not just the well-known fundamental acoustical mode. These modes display both circumferential and radial pressure variations within the tire's air cavity. The theory governing these modes has thus been investigated. A brief recapitulation of the previously-presented coupled structural-acoustical model based on a tensioned string approach will be given, and then an improved tire-acoustical model with a ring-like shape will be introduced. In the latter model, the effects of flexural and circumferential stiffness are considered. This improved model accounts for propagating in-plane vibration in addition to the essentially structure-borne flexural wave and the essentially airborne longitudinal wave accounted for in the previous model. The longitudinal structure-borne wave “cuts on” at the tire's circumferential ring frequency.
2015-06-15
Technical Paper
2015-01-2197
Stijn Vercammen, Fabio Bianciardi, Peter Kindt, Wim Desmet, Paul Sas
Abstract In the context of the reduction of traffic-related noise the research reported in this paper provides tools that could be used to develop low noise tyres. Two measurement techniques have been analyzed for exterior noise radiation characterization of a loaded rotating slick tyre on a rough road surface. On one hand sound pressure measurements at low spatial resolution with strategically placed microphones on a half-hemisphere around the tyre/road contact point have been performed. This technique provides a robust solution to compute the (overall) sound power level. On the other hand sound intensity measurements at high spatial resolution by means of a scanning intensity probe have been performed. This technique allows a more detailed spatial visualization of the noise radiation and helps in getting more insight and better understanding of the acoustical phenomena.
2015-06-15
Technical Paper
2015-01-2233
Hudson P Vijayakumar, V Shivaraj, T Sukumar, Suresh Gaikwad
Abstract Generally the brake system products are mounted on chassis with brackets which are subjected to dynamic loads due to road undulations. Exhaust brake is used to restrict the engine exhaust flow passage and thereby creates a back pressure in the engine for reducing the engine speed. This in turn reduces the vehicle speed. This is widely used in the vehicles operating in the hilly areas. This product is mounted on the exhaust passage and the air cylinder sub-assembly which actuates the exhaust brake is mounted on a bracket. Automotive industries perform durability tests on vehicles to reduce the failure on end-user environment. An assembly which has cleared the durability test got failed on addition of a spring into the assembly. The inclusion of spring is for enhancing the performance of the overall assembly.
2015-06-12
Standard
J294_201506
This SAE Recommended Practice establishes a method of testing the structural integrity of the brake system of all new trucks, buses, and combination vehicles designed for roadway use and falling in the following classifications: a. Trucks and Bus— Over 4500 kg (10 000 lb) GVWR b. Combination of vehicle—Towing vehicle over 4500 kg 10 000 lb) GVWR The test consists of two parts: a Structural EnduranceTest followed by a Structural Ultimate Strength Test.
2015-06-10
Article
Automotive Engineering is serving as media partner for the 2015 Altair Enlighten Award. In collaboration with the Center for Automotive Research (CAR), the annual award recognizes achievements in lightweighting across the automotive industry and will be presented during the CAR Management Briefing Seminars (MBS), August 3-5 in Traverse City, MI.
2015-06-05
Article
Bosch upgrades ABS module for stability control that doesn't intrude.
2015-06-03
Magazine
Executive Viewpoints Off-highway industry executives from companies such as BorgWarner, Perkins, Cummins, and Danfoss reflect upon challenges inside, and outside, the industry, and what technologies, innovations, and strategies will need to be implemented to thrive into the long-term future. 16th Annual Product Guide Top products from throughout the industry covering technologies such as Powertrain & Energy, Hydraulics, Electronics, and Testing & Simulation.
2015-05-27
Article
Efforts to replace tropical rubber trees with a wild desert shrub that grows in Southwestern U.S. and Mexico are just beginning to bear fruit.
2015-05-26
WIP Standard
J656
This SAE Recommended Practice identifies and defines terms specifically related to brake systems.
2015-05-20
Article
A custom tractor-trailer technology demonstrator built by Alcoa is outfitted with various current and “soon-to-be-available” aluminum solutions that altogether can reduce the weight of a tractor-trailer by up to 2500 lb (1135 kg) compared to traditional steel components.
2015-05-13
Technical Paper
2015-36-0006
Erik Camargo, Claudio Fernandes, Leopoldo Sprandel, Romulo Castro, Rodrigo Sousa, Leandro Roza, Marcio Ciolfi
Abstract This paper focused on pedal feeling studies at most often longitudinal decelerations for the normal daily usage of customers. Such decelerations were defined in vehicle equipped with sensors in a specific itinerary near Resende/Penedo city (southeastern Brazil) with several clients using the same vehicles. Through the decelerations acquired, one could correlate, objectively and subjectively, the pedal effort and travel that delight the customers, reaching the so called ideal pedal feeling. The mapping provides the needed input data to develop, or adapt, a vehicle to the best condition expected by consumers.
2015-05-13
Technical Paper
2015-36-0004
Patric Daniel Neis, Ney Francisco Ferreira, Luciano Tedesco Matoso, Diego Masotti, Jean Carlos Poletto
Abstract The present paper addresses an investigation about the definition of a parameter for quantifying the creep-groan propensity in brake pads. Creep-groan is a self-excited vibration caused by stick-slip phenomenon [1, 2, 3]. For the definition of the creep-groan propensity parameter, extensive experimental work was performed on a laboratory-scale tribometer. The experiments are divided in two main parts: (i) study of correlation between accelerometer signal with physical and operating parameters. (ii) validation of the chosen parameter, which was based on stick-slip tests performed with three different materials, one low-metallic (low-met) and two non-asbestos organic (NAO 1 and 2). From the first study, it was found that both the slip power and mean torque multiplied by torque variation showed a slightly higher correlation with the acceleration signal.
2015-05-13
Technical Paper
2015-36-0002
Keshav Sundaresh, Felipe Moretti Leila
Abstract The level of noise transmitted to the passengers of a vehicle can drastically impact a passenger's comfort. Brake noise will give the customer an impression of poor product quality and can thus damage the quality image of the company. Within the automotive industry, the study of mode coupling instability by the use of FEM and modal complex analysis is widespread to reduce this phenomenon. In this paper an alternative method is presented, where potential brake noise issues are predicted by the use of a time transient integration using multi-body system analysis. The simulation model contains a nonlinear contact description, bushing, flexible bodies and the axis kinematics of the vehicle. Transient results are transformed by Fourier for a frequency domain study. The parameters that can be varied for the prediction analysis are brake pressure, vehicle speed, friction laws, system damping and bushing properties.
2015-05-13
Technical Paper
2015-36-0028
Patric Daniel Neis, Ney Francisco Ferreira, Jean Carlos Poletto
Abstract The current paper addresses the comparative analysis of the performance (friction and wear) produced by original and aftermarket brake pads. The brake pads selected in this study belongs to a large circulation vehicle in Brazil, which also has a high number of sales. An original and 4 others aftermarket brake pads were purchased at Porto Alegre, Brazil. The braking tests were performed on a braking tribometer, which is located on the University facilities. Experimental data of the coefficient of friction produced by each brake pad have been recorded. A precision scale was used to measure the mass loss of the materials subjected to the tests. Results of the performance obtained by the brake pads are evaluated and discussed in this paper. Results have shown that the original brake pad has superior properties in terms of friction performance (magnitude and variation), while aftermarket 1 and aftermaket 2 materials have the lowest vibration magnitudes.
2015-05-13
Technical Paper
2015-36-0026
André G. L. Suetti, Robson Pederiva
Abstract In the field of engineering, there is a well known phenomenon called “stick-slip” a specific type of vibration in a mechanical system where friction is involved, it is qualified as non-linear, auto-excited and generally stable within a limited cycle. During stick-slip, the behavior of the friction coefficient as a function of the sliding velocity has big influence on the wave pattern, wherein various models can be found in the literature. Besides affecting wave patterns, this behavior affects significantly the amount of damping necessary to reach an asymptotic level of stability. The objective of this work is to study various friction models found in literature, for example: constant transition between coefficients, linear and exponential and apply these models in mechanical systems that represent brake systems.
2015-05-13
Technical Paper
2015-36-0024
Thomas Gillespie, Vinicius de A. Lima
Abstract Heavy trucks with solid front axles commonly use steering systems that have left to right asymmetry. The asymmetry creates the potential to cause steering pulls during brake application which are by their nature undesirable since they require an input in the steering wheel by the driver to maintain the correct path of the vehicle. Brake forces acting in the tire contact patches create toe-out moments around the kingpin axes that are resisted by the steering linkages. However asymmetry of the linkage allows unbalanced toe-out steer angle deviations at the wheels resulting in a path deviation of the truck that is perceived as brake steering pull. The factors influencing steering pull include the compliance properties of the steering linkages, road wheel geometry, drag link geometry and spring windup properties. The mechanics of the brake force interactions with these steering and suspension properties are explained here.
2015-05-13
Technical Paper
2015-36-0020
Carlos Abílio Passos Travaglia, Adan Araujo Rodrigues, Luiz Carlos Rolim Lopes
Abstract In engineering development, simulation methods are frequently used to perform thermal and mechanical stress components analysis. In brake systems, where the components are exposed to mechanical and thermal loads, the numerical analysis is very helpful. Once a numerical model for brake assembly is available, it will be possible to understand the effects of successive brake applications on the temperature distribution in drum brake's friction materials. This is a fundamental aspect to determine, for instance, the thermal stress distribution which is related to the warming and cooling of the brakes. In this work, an analytical solution to calculate stabilized temperature was used to establish a heat flux through a pneumatic S cam drum brake's friction material applied to a numerical model in a finite element analysis.
2015-05-13
Technical Paper
2015-36-0019
Márcio J. Ciolfi, Paulo E. B. de Mello
Abstract This paper presents the different “gradients” of heat transfer coefficients found in a usual ventilated brake disc type. Although the conduction coefficient depends on the material characteristics applied, the convection and radiation coefficients changes as function of vehicle speed and brake temperature respectively. By comparing the coefficients magnitude orders of each surface and condition is possible to define the most favorable geometries for cool down the system.
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