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Viewing 91 to 120 of 10889
2017-03-28
Journal Article
2017-01-0411
Yuming Yin, Subhash Rakheja, Jue Yang, P-E. Boileau
Abstract This study is aimed at characterizing the nonlinear stiffness and damping properties of a simple and low cost design of a hydro-pneumatic suspension (HPS) that permits entrapment of gas into the hydraulic fluid. The mixing of gas into the oil yields highly complex variations in the bulk modulus, density and viscosity of the hydraulic fluid, and the effective gas pressure, which are generally neglected. The pseudo-static and dynamic properties of the HPS strut were investigated experimentally and analytically. Laboratory tests were conducted to measure responses in terms of total force and fluid pressures within each chamber under harmonic excitations and nearly steady temperature. The measured data revealed gradual entrapment of gas in the hydraulic fluid until the mean pressure saturated at about 84% of the initial pressure, suggesting considerably reduced effective bulk modulus and density of the hydraulic fluid.
2017-03-28
Journal Article
2017-01-0419
Yuliang Yang, Yu Yang, Ying Sun, Jian Zeng, Yunquan Zhang
Abstract In addition to ride comfort, handling stability and other conventional vehicle performances, we should also focus on other aspects of performance to a center axle trailer combination, such as the maximum stable side-inclination, the anti-rolling stability, the lateral stability and so on. Based on the finite element method, a rigid-flexible coupling model for the truck combination was built and analyzed in the multi-body environment (ADAMS), in which the key components of the chassis and cab suspension were treated as flexible bodies. A series of simulations were carried out to evaluate the lateral stability of the center axle trailer in accordance with the relevant regulations of the vehicle. The influence of design variables on the lateral stability was studied by an experiment. Furthermore, in order to improve the lateral stability of the trailer combination, the optimal design was obtained by the co-simulation of the ADAMS/Car, iSIGHT and Matlab.
2017-03-28
Journal Article
2017-01-0437
Bin Li, Subhash Rakheja
The directional and handling responses of articulated heavy vehicles are known to be somewhat less predictable, particularly under emergency-type maneuvers. This poses complex control challenges for the driver and the road safety. Moreover, the yaw stability of an articulated vehicle is very sensitive to vehicle forward velocity and cargo load, which could vary considerably. The vast majority of the active safety control strategies in the literature, however, focus on assessments of stability limits and controller considering constant forward speed. In this paper, a gain-scheduling optimal control technique is proposed for enhancing yaw stability limits of articulated commercial vehicles considering a broad range of forward speeds. For this purpose, an optimal feedback control method is used to design a family of yaw moment controllers corresponding to different vehicle velocities.
2017-03-28
Journal Article
2017-01-1554
Ajith Jogi, Sujatha Chandramohan
Abstract Over the years, commercial vehicles, especially tractor-semitrailer combinations have become larger and longer. With the increasing demand for their accessibility in remote locations, these vehicles face the problem of off-tracking, which is the ensuing difference in path radii between the front and rear axles of a vehicle as it maneuvers a turn. Apart from steering the rear axle of the semitrailer, one of the feasible ways of mitigating off-tracking is to shift the fifth wheel coupling rearwards. However, this is limited by the distribution of the semitrailer’s load between the two axles of the tractor; any rearward shift of the fifth wheel coupling results in the reduction of the total static load on the tractor’s front axle and hence available traction. This may in turn lead to directional instability of the vehicle. In the present work, a new model of the fifth wheel coupling is proposed which the authors call Split fifth wheel coupling (SFWC).
2017-03-28
Journal Article
2017-01-1519
Arturo Guzman, Young-Chang Cho, John Tripp, Kumar Srinivasan
Abstract Pickup trucks are designed with a taller ride height and a larger tire envelope compared to other vehicle types given the duty cycle and environment they operate in. These differences play an important role in the flow field around spinning wheels and tires and their interactions with the vehicle body. From an aerodynamics perspective, understanding and managing this flow field are critical for drag reduction, wheel design, and brake cooling. Furthermore, the validation of numerical simulation methodology is essential for a systematic approach to aerodynamically efficient wheel design as a standard practice of vehicle design. This paper presents a correlation the near-wheel flow field for both front and rear spinning wheels with two different wheel designs for a Ram Quad Cab pick-up truck with moving ground. Twelve-hole probe experimental data obtained in a wind tunnel with a full width belt system are compared to the predictions of numerical simulations.
2017-03-28
Technical Paper
2017-01-1581
Jianbo Lu, Hassen Hammoud, Todd Clark, Otto Hofmann, Mohsen Lakehal-ayat, Shweta Farmer, Jason Shomsky, Roland Schaefer
Abstract This paper presents two brake control functions which are initiated when there is an impact force applied to a host vehicle. The impact force is generated due to the host vehicle being collided with or by another vehicle or object. The first function - called the post-impact braking assist - initiates emergency brake assistance if the driver is braking during or right after the collision. The second function - called the post-impact braking - initiates autonomous braking up to the level of the anti-lock-brake system if the driver is not braking during or right after the collision. Both functions intend to enhance the current driver assistance features such as emergency brake assistance, electronic stability control, anti-brake-lock system, collision mitigation system, etc.
CURRENT
2017-03-21
Standard
AS5714
This SAE Aerospace Standard (AS) prescribes the Minimum Performance Standards (MPS) for wheel, brake, and wheel and brake assemblies to be used on aircraft certificated under 14 CFR Parts 23, 27, and 29. Compliance with this specification is not considered approval for installation on any aircraft.
2017-03-13
Article
Startup-company Twin Spring Coupling features its new power transfer coupling that is warrantied to 300 lb·ft (407 N·m) of torque.
CURRENT
2017-03-13
Standard
J2995_201703
This recommended practice will specify a standard duty cycle and set of conditions for component-level durability testing. The "duty cycle" refers to a set of loading conditions (e.g. torque or pressure and cycling count), and the 'test conditions" refers to environmental conditions such as temperature, humidity, and part conditioning from prior exposure (e.g. heat aging).
2017-02-13
WIP Standard
J2789
This Recommended Practice is useful to determine the inertia value (wheel load and tire radius) using three basic methods (fixed brake work split, dynamic weight transfer, and axle rating) to determine the wheel load and two methods to determine the tire radius (SLR and rolling radius). The inertia values are required to determine the amount of energy and brake work imposed on the brake during testing. The inertia level (mechanical or simulated) is required also to calculate deceleration levels from a given torque value or the torque level for a given deceleration value or set-point. This procedure is applicable to all passenger cars and light trucks up to 4,540kg of GVWR.
CURRENT
2017-02-13
Standard
J2611_201702
This SAE information report covers the basic guidelines concerning off-road tire conditions that warrant replacement, removal, or repair. This material can assist the tire user in establishing specific written procedures for each job site.
2017-02-10
WIP Standard
J2899
This SAE Recommended Practice applies to S-CAM, Wedge, and Disc air brake actuators where the stroke can be measured without disassembly from the brake.
2017-02-09
Article
UQM Technologies signed a development agreement with Meritor to jointly develop E-axles for the medium- and heavy-duty EV commercial market, according to a February 2 announcement. Prototypes are expected by early fall of 2017.
CURRENT
2017-02-09
Standard
J1469_201702
This SAE Recommended Practice provides procedures and methods for testing service, spring applied parking, and combination brake actuators with respect to durability, function, and environmental performance. A minimum of six test units designated A, B, C, D, E, and F are to be used to perform all tests per 1.1 and 1.2.
2017-02-09
WIP Standard
J2247
This SAE Recommended Practice identifies the minimum truck tractor electrical power output of the stop lamp and ABS (antilock brake system) circuits measured at the primary SAE J560 tractor trailer interface connector(s).
CURRENT
2017-02-02
Standard
J2581_201702
This SAE Information report defines the thermal transport properties important in the assessment of heat management capability of brake lining, shoe, disc and drum materials. The report discusses thermal diffusivity, specific heat capacity, thermal conductivity and thermal expansion. Measurement techniques for the appropriate ASTM standards are identified. The thermal transport properties discussed are material sample properties, not the properties of entire components such as pad assemblies.
CURRENT
2017-02-02
Standard
J380_201702
Specific gravity is a nondestructive test used as a quality control check of the consistency of formulation and processing of brake lining. The specific gravity and the range of specific gravity are peculiar to each formulation and, therefore, the acceptable values or range must be established for each formulation by the manufacturer. Specific gravity alone shows nothing about a materials in use performance. The specific gravity of sintered metal powder friction materials, particularly those which have steel backing members, is usually determined somewhat differently. Reference ASTM B 376. Purpose To establish a uniform procedure for determining the specific gravity of brake friction material.
CURRENT
2017-02-02
Standard
J379_201702
Hardness measurements are used as a quality control check of the consistency of formulation and processing of brake linings. Gogan hardness is nondestructive (the penetrator causes shallow surface deformation.). Gogan hardness method alone does not show anything about a lining’s ability to develop friction or to resist fade when used as a friction element in brakes. The hardness and the range of hardness are peculiar to each formulation, thickness, and contour; therefore, the acceptable values and ranges must be established for each formulation and part configuration by the manufacturer.
2017-01-31
WIP Standard
AIR6417
This Aerospace Information Report (AIR) provides information related to experience with carbon brake quality-assurance rejected takeoff tests, and considerations regarding test setup, test conditions, test frequency and cost considerations.
2017-01-25
Article
Dr. Christian Wiehen, Chief Technology Officer for WABCO, discusses ADAS, platooning and automated future for trucks.
2017-01-23
Article
Volvo Construction Equipment offers increased payload capacities among other features on the new A45G articulated hauler.
CURRENT
2017-01-12
Standard
ARP5429A
This SAE Aerospace Recommended Practice (ARP) applies to fatigue testing of landing gear and landing gear components.
2017-01-10
Technical Paper
2017-26-0220
Ashutosh Dubey, Palish Raja, Nitin Chopra, Ashok Patidar, Manu Kaushik
Abstract With the increase in the sensitivity of power steering system in the competitive environment, it becomes essential to provide a trouble free steering system to the customer. Usually major concerns faced in the performance of steering system are related to noise like vane pump whining noise and steering gearbox erratic rubbing noise. Even though selected steering pump and reservoir are quite compatible to the steering gearbox. With the series of Computational Fluid Dynamics (CFD) simulations and field tests, it is found that the cavitation phenomena in steering oil routing lines is responsible for the steering turning noise. In this paper, a developed systematic approach for problem detection to implementation of design solution is discussed.
2017-01-10
Technical Paper
2017-26-0218
Chaitanya Chilbule, S B Phadke, R N Kulkarni, M P Raajha
Abstract As an automobile brake manufacturer, brake noise always been a prime concern as it define the degree of customer satisfaction and warranty claim. Brake squeal is a concern in the automotive industry that has challenged many researchers and engineers for years. In case of disc brake, brake-squeal (1 to 16 kHz) occurrence is predominant than the any other types of brake-noise (i.e. moan, grown, judder etc.), since squeal is a friction induced, self-excited, and self-sustained phenomenon from a nonlinear dynamics viewpoint. Due to the complexities involve squeal mechanism is not well understood yet, hence makes it one of the unresolved brake Noise, Vibration, and Harshness (NVH) problem till this date. Since squeal is a high-pitched and tonal noise, therefore it is very annoying and getting more attention by occupants. Brake squeal can occur at any temperature and with or without the presence of humid condition and therefore highly unpredictable.
2017-01-10
Technical Paper
2017-26-0261
Ashesh Anil Shah, Ashok Patidar
Abstract Paper explains conversion of existing drum brake system to disc brake system with complete digital validation at structural as well as thermal level to make sure First Time Right Design before physical part development. To provide leverage to quick design, modification and selection of brake system according to vehicle configuration, a virtual computational fluid dynamics (CFD) simulation process is developed and validated with test results. Temperature variation over brake drum and disc in internal standard braking cycle is measured virtually and correlated with test results. Also Fade testing criteria’s were considered during CFD analysis. This up gradation is must considering technology enhancement trend and safety in automotive segment. In current competitive market scenario and as per customer requirements, front disc brake module is becoming necessary not only for passenger segment but also for commercial segment vehicle.
2017-01-10
Technical Paper
2017-26-0259
Sandeep V. Sawangikar, Jeevan N. Patil, Sivakumar Palanivelu, Arun Kumar K
Abstract Steering system deliver a precise directional control to the vehicle chassis and ensure the safe driving at all maneuvers. Hydraulic power assisted system (HPAS) helps drivers to steer by boosting steering assistance of the steering wheel while retaining the road feel. HPAS performance is associated with the design characteristics of rotary valve, steering, suspension, kinematics, brake, tire, vehicle speed and load transfer. Thus a detailed power steering system model is absolutely necessary to evaluate and optimize the performance characteristics. However, many components of HPAS system are proprietary in nature so it is very challenging to get component characteristic of each sub-system for the complete power steering system model. Hence, it is very important to establish a technique to extract all such influencing characteristics with available test facility.
2017-01-10
Technical Paper
2017-26-0246
Srinivas Kurna, Ruchik Tank
Abstract The job of a suspension system is to maximize the friction between the tires and the road surface, to provide steering stability with good handling and to act as a cushioning device to ensure the comfort of the driver and passengers. The suspension system also protects the vehicle and any cargo or luggage from damage and wear. Commonly the strength of these suspension systems is evaluated by endurance trials on field or Rig testing which are time consuming and costly. On the other hand, virtual testing methods for strength and stiffness evaluation provide useful information early in the design cycle and save significant time and cost. However, the virtual method also needs validation, which can be achieved by physical co-relations (via rig tests). A study has been done to predict the behavior of Leaf Spring Suspensions entirely through the FEA (Finite Element Analysis) route and correlating those results with physical test.
2017-01-10
Technical Paper
2017-26-0080
P. Ramani Ranjan Senapati, Soumyo Das, Prashantkumar B. Vora
Abstract The development of intelligent driver assistance mechanism ensures safety and comfort of passengers, the intelligent braking and maneuvering mechanism is proposed by transforming the anti-lock braking technology for a four wheeled vehicle. This paper presents an active safety mechanism which incorporates both steering and braking assistance system in a maneuvering vehicle. The algorithm of collision avoidance mechanism is featured and interfaced in an intelligent vehicle with short range radar to assist driving system of host vehicle based on predicted motion of sensed obstacles. The developed system will be activated for obstacles in front of the host vehicle within critical risk level. The intelligent braking mechanism plays a pivotal role at the time of emergency situation depending on the predicted collision time and relative velocity between host and target, it also provides assistance to avoid panic situation for driver.
2017-01-10
Technical Paper
2017-26-0312
Sagar Polisetti, Ganeshan Reddy
Abstract Twist beam is a type of suspension system that is based on an H or C shaped member typically used as a rear suspension system in small and medium sized cars. The front of the H member is connected to the body through rubber bushings and the rear portion carries the stub axle assembly. Suspension systems are usually subjected to multi-axial loads in service viz. vertical, longitudinal and lateral in the descending order of magnitude. Lab tests primarily include the roll durability of the twist beam wherein both the trailing arms are in out of phase and a lateral load test. Other tests involve testing the twist beam at the vehicle level either in multi-channel road simulators or driving the vehicle on the test tracks. This is highly time consuming and requires a full vehicle and longer product development time. Limited information is available in the fatigue life comparison of multi-axial loading vs pure roll or lateral load tests.
2017-01-10
Technical Paper
2017-26-0313
Manoj Kumar Rajendran, Srinivasa Chandra V, Manikandan Rajaraman, Dinesh Kumar Rajappan, Agathaman Selvaraj
Abstract In today competitive world, gaining customer delight is the most vital part of an automotive business. Customers’ expectations are high which need to be satisfied limitless, to stay in the business. The major expectation of a commercial vehicle customer is a vehicle without failures which involves lower spares cost and downtime. The significance of a suspension system in the new age automobiles is getting advanced. There have been many improvements in the suspension system especially in leaf springs to provide a better ride comfort, and one such modern era implementation is the Parabolic Spring which comprises of fewer leaves with varying thickness from the center to the ends without inter-leaf friction. Study reveals that parabolic spring exhibits better ride comfort, but less life compared to a conventional leaf spring which leads to the increase in downtime of the vehicle.
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