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Viewing 211 to 240 of 9372
2016-04-05
Journal Article
2016-01-0476
Yongchang Du, Yingping Lv, Yujian Wang, Pu Gao
Abstract Brake squeal is a complex dynamics instability issue for automobile industry. Closed-loop coupling model deals with brake squeal from a perspective of structural instability. Friction characteristics between pads and disc rotor play important roles. In this paper, a closed-loop coupling model which incorporates negative friction-velocity slope is presented. Different from other existing models where the interface nodes are coupled through assumed springs, they are connected directly in the presented model. Negative friction slope is taken into account. Relationship between nodes’ frictional forces, relative speeds and brake pressure under equilibrant sliding and vibrating states is analysed. Then repeated nodal coordinate elimination and substructures’ modal coordinate space transformation of system dynamic equation are performed. It shows that the negative friction slope leads to negative damping items in dynamic equation of system.
2016-04-05
Journal Article
2016-01-0477
Pu Gao, Yongchang Du, Yujian Wang, Yingping Lv
Abstract The dynamic properties of disc rotor play important role in the NVH performance of a disc brake system. Disc rotor in general is a centrosymmetric structure. It has many repeated-root modes within the interested frequency range and they may have significant influence on squeal occurrence. A pair of repeated-root modes is in nature one vibration mode. However, in current complex eigenvalue analysis model and relevant analysis methods, repeated-root modes are processed separately. This may lead to contradictory result. This paper presents methods to deal with repeated-root modes in substructure modal composition (SMC) analysis to avoid the contradiction. Through curve-fitting technique, the modal shape coefficients of repeated-root modes are expressed in an identical formula. This formula is used in SMC analysis to obtain an integrated SMC value to represent the total influence of two repeated-root modes.
2016-04-05
Journal Article
2016-01-1122
Hyungsouk Kang, TaeYoung Chung, Hyeongcheol Lee, Hyungbin Ihm
Abstract Pressure variation during engine combustion generates torque fluctuation that is delivered through the driveline. Torque fluctuation delivered to the tire shakes the vehicle body and causes the body components to vibrate, resulting in booming noise. HKMC (Hyundai Kia Motor Company)’s TMED (Transmission Mounted Electric Device) type generates booming noises due to increased weight from the addition of customized hybrid parts and the absence of a torque converter. Some of the improvements needed to overcome this weakness include reducing the torsion-damper stiffness, adding dynamic dampers, and moving the operation point of the engine from the optimized point. These modifications have some potential negative impacts such as increased cost and sacrificed fuel economy. Here, we introduce a method of reducing lock-up booming noise in an HEV at low engine speed.
2016-04-05
Journal Article
2016-01-1181
Takao Watanabe, Tadashi Fujiyoshi, Akira Murakami
Abstract In the present paper, we introduce a drivetrain system using an electromagnetic coupling for hybrid electric vehicles, and propose a new control concept of vibration torque interception. The electromagnetic coupling is an electric machine that is composed of a pair of rotors, and electromagnetic torque acts mutually between the rotors. In the drivetrain system, the electromagnetic coupling works as a torque transmission device with a rotational-speed-converting function. We demonstrate that, by using this control, the electromagnetic coupling also works as a damping device that intercepts the vibration torque of the internal combustion engine, while transmitting the smooth torque to its drive line. Using a model of a two-inertia resonance system, a control system is designed such that a transfer function representing input-to-output torque is shaped in the frequency domain.
2016-04-05
Journal Article
2016-01-1299
Robert S. Ballinger
Abstract The complex eigenvalue analysis has been used by the brake research community to study friction-induced squeal in automotive disk brake assemblies. The analysis process uses a nonlinear static pre-stressed normal modes analysis simulation sequence followed by a complex eigenvalue extraction algorithm to determine the dynamic instabilities. When brake hardware exists, good correlation between analysis results and experimental data can be obtained. Consequently, complex eigenvalue analysis can be a valuable method in an effort to understand brake components that might have a propensity to influence the noise behavior of a brake system. However, when hardware does not exist and the complex eigenvalue method is asked to be predictive, it becomes a difficult, if not impossible task. This paper will focus on some of the reasons the complex eigenvalue analysis method is not a reliable predictor of friction-induced squeal in automotive disk brake assemblies.
2016-04-05
Journal Article
2016-01-1315
Yongchang Du, Yingping Lv, Yujian Wang, Pu Gao
Abstract Closed-loop coupling model, based on complex eigenvalue analysis, is one of the most popular and effective methods for brake squeal analysis. In the model, imaginary coupling springs are used to represent the normal contacting force between coupled nodes. Unfortunately, the physical meaning of these coupling springs was seldom discussed and there’s no systematic method to determine the value of spring stiffness. Realizing this problem, this paper, based on finite element model and modal synthesis technique, develops a new closed-loop coupling disc brake squeal model without introducing imaginary coupling springs. Different from the traditional model where two nodes at coupling interface are connected through a spring, these node-pairs in the new model are assumed to remain in tight contact during vibration. Details of the model, including force analysis, coordinate reduction and transformation and complex eigenvalue decomposition are given in this paper.
2016-04-05
Journal Article
2016-01-0277
Xingxing Feng, Kaimin Zhuo, Jinglai Wu, Vikas Godara, Yunqing Zhang
Abstract Interval inverse problems can be defined as problems to estimate input through given output, where the input and output are interval numbers. Many problems in engineering can be formulated as inverse problems like vehicle suspension design. Interval metrics, instead of deterministic metrics, are used for the suspension design of a vehicle vibration model with five degrees of freedom. The vibration properties of a vehicle vibration model are described by reasonable intervals and the suspension interval parameters are to be solved. A new interval inverse analysis method, which is a combination of Chebyshev inclusion function and optimization algorithm such as multi-island genetic algorithm, is presented and used for the suspension design of a vehicle vibration model with six conflicting objective functions. The interval design of suspension using such an interval inverse analysis method is shown and validated, and some useful conclusions are reached.
2016-04-05
Journal Article
2016-01-1395
Syed F. Haider, Zissimos Mourelatos
Abstract To improve fuel economy, there is a trend in automotive industry to use light weight, high strength materials. Automotive body structures are composed of several panels which must be downsized to reduce weight. Because this affects NVH (Noise, Vibration and Harshness) performance, engineers are challenged to recover the lost panel stiffness from down-gaging in order to improve the structure borne noise transmitted through the lightweight panels in the frequency range of 100-300 Hz where most of the booming and low medium frequency noise occurs. The loss in performance can be recovered by optimized panel geometry using beading or damping treatment. Topography optimization is a special class of shape optimization for changing sheet metal shapes by introducing beads. A large number of design variables can be handled and the process is easy to setup in commercial codes. However, optimization methods are computationally intensive because of repeated full-order analyses.
2016-04-05
Journal Article
2016-01-1543
Donald F. Tandy, Scott Hanba, Robert Pascarella
Abstract One important part of the vehicle design process is suspension design and tuning. This is typically performed by design engineers, experienced expert evaluators, and assistance from vehicle dynamics engineers and their computer simulation tools. Automotive suspensions have two primary functions: passenger and cargo isolation and vehicle control. Suspension design, kinematics, compliance, and damping, play a key role in those primary functions and impact a vehicles ride, handling, steering, and braking dynamics. The development and tuning of a vehicle kinematics, compliance, and damping characteristic is done by expert evaluators who perform a variety of on road evaluations under different loading configurations and on a variety of road surfaces. This “tuning” is done with a focus on meeting certain target characteristics for ride, handling, and steering One part of this process is the development and tuning of the damping characteristics of the shock absorbers.
2016-04-05
Technical Paper
2016-01-1057
Masaya Miyazawa, Kei Mochizuki, Kondo Takashi
Abstract To achieve lightweight, low friction and fuel efficient engine, the crankshaft is required to be designed lightweight, small-diameter shaft, long stroke. In this case, vibration of the crankshaft is increased by reduction of shaft stiffness. The conventional way of dealing with this increased vibration used to be to add an inertia mass ring or a double mass damper. Such an approach, however, increases weight, making the balance of weight reduction and vibration reduction less readily achieved. This paper therefore reports on how the main factors causing crankshaft vibration to increase in the shaft with reduced stiffness were clarified. Based on that clarification, efforts were made to reduce crankshaft vibration without increasing the weight of the crankshaft system. Measurement and analysis were used to analyze crankshaft vibration during operation.
2016-04-05
Journal Article
2016-01-1678
Etsuo Katsuyama, Ayana Omae
Abstract Vehicles equipped with in-wheel motors (IWMs) are capable of independent control of the driving force at each wheel. These vehicles can also control the motion of the sprung mass by driving force distribution using the suspension reaction force generated by IWM drive. However, one disadvantage of IWMs is an increase in unsprung mass. This has the effect of increasing vibrations in the 4 to 8 Hz range, which is reported to be uncomfortable to vehicle occupants, thereby reducing ride comfort. This research aimed to improve ride comfort through driving force control. Skyhook damper control is a typical ride comfort control method. Although this control is generally capable of reducing vibration around the resonance frequency of the sprung mass, it also has the trade-off effect of worsening vibration in the targeted mid-frequency 4 to 8 Hz range. This research aimed to improve mid-frequency vibration by identifying the cause of this adverse effect through the equations of motion.
2016-04-01
WIP Standard
J1192
This standard established the requirements and test procedures for the operational life, corrosion resistence, and sound pressure level of motorcycle electric and electro pnuematic audible warning deveices. Test equipment, environment, and procedures are specified.
2016-03-31
Article
Ford's 6.7-L diesel V8 has yet to obtain certified power ratings, but it's expected to exceed 900 lbft of torque, necessitating an upgrade of the company's dyno sleds to enable SAE J2807 vehicle tow testing.
2016-03-27
Article
Self-driving car project CEO John Krafcik discussed Google's work underway toward fully autonomous vehicles, at a recent NY forum. First likely market: the elderly and impaired.
2016-03-25
WIP Standard
AS8017D
This SAE Aerospace Standard (AS) establishes minimum performance standards for new equipment anticollision light systems.
2016-03-25
WIP Standard
AIR5661A
This report provides data and general analysis methods for calculation of internal and external, pressurized and unpressurized airplane compartment pressures during rapid discharge of cabin pressure. References to the applicable current FAA and EASA rules and advisory material are provided. While rules and interpretations can be expected to evolve, numerous airplanes have been approved under current and past rules that will have a continuing need for analysis of production and field modifications, alterations and repairs. The data and basic principles provided by this report are adaptable to any compartment decompression analysis requirement.
2016-03-24
Article
In this Q&A, Toyota Technical Center President Seiya Nakao discusses future mobility development, technical innovation, Toyota's recent reorganization, and the ever-changing automotive engineering profession.
2016-03-14
Article
As airlines strive to move more and more people faster and faster, the talk of a future supersonic aircraft for commercial purposes is getting louder and louder.
2016-03-14
Journal Article
2016-01-9108
Ji Xu, Guohua Sun, Tao Feng, Mingfeng Li, Teik Lim
Abstract Active noise control systems have been gaining popularity in the last couple of decades, due to the deficiencies in passive noise abatement techniques. In the future, a novel combination of passive and active noise control techniques may be applied more widely, to better control the interior sound quality of vehicles. In order to maximize the effectiveness of this combined approach, smarter algorithms will be needed for active noise control systems. These algorithms will have to be computationally efficient, with high stability and convergence rates. This will be necessary in order to accurately predict and control the interior noise response of a vehicle. In this study, a critical review of the filtered-x least mean square (FXLMS) algorithm and several other newly proposed algorithms for the active control of vehicle powertrain noise, is performed. The analysis examines the salient features of each algorithm, and compares their system performance.
2016-03-07
Article
The POSIWIRE sensor WS21 from ASM Sensors is designed for measuring ranges up to 20,000 mm.
2016-03-06
Article
Cambustion’s DPG, an automated particle filter testing system, can be used to load diesel particulate filters (DPFs) and now gasoline particulate filters (GPFs) with ash over a matter of hours, the company claims. This is a new application of the DPG for studying the effects of ash build-up in particulate filters.
2016-03-04
Article
A solution from Spirent Communications will help reduce the development time and cost of automotive Ethernet/BroadR-Reach systems.
2016-03-03
Magazine
Multi-material structures move mpg upward The quest to improve fuel economy is not waning, nor is the desire to achieve higher mpg through the use of just the right lightweight material for the right vehicle application. Cars poised to become 'a thing' Making automobiles part of the Internet of Things brings both risks and rewards. Agility training for cars Chassis component suppliers refine vehicle dynamics at the high end and entry level with four-wheel steering and adaptive damping. SAE 2016 World Congress Preview Technology trends and exhibitor products are highlighted in this special section, which features Toyota's plans for the show floor, tech sessions, and more.
2016-03-01
Article
The growing role of electronics and software is altering the design process, requiring a greater focus on validation and verification, particularly to meet the stringent demands of off-highway environments.
2016-02-29
Article
Three SAE standards are to be incorporated in EPA regulations, including refrigerant identification, built-in or via USB on hand-held units, incorporated in requirements for recovery/recycle/recharge equipment. There's also a standard for testing internal heat exchangers in development.
2016-02-11
WIP Standard
AIR1839D
This Aerospace Information Report (AIR) is a general overview of typical airborne engine vibration monitoring (EVM) systems applicable to fixed or rotary wing aircraft applications, with an emphasis on system design considerations. It describes EVM systems currently in use and future trends in EVM development. The broader scope of Health and Usage Monitoring Systems, (HUMS ) is covered in SAE documents AS5391, AS5392, AS5393, AS5394, AS5395, AIR4174.
2016-02-03
Article
Britain has established a real-world test highway for connected and autonomous vehicle technologies. JLR is one of the companies investing in the 66-km-long R&D route.
2016-02-02
Article
Imetrum’s precision, noncontact 3D measurement system, the Precision Displacement Tracker, slashes setup times and provides richer data sets without compromising measurement resolution or sampling speed.
2016-02-02
Article
Intertek’s Milton Keynes Transportation Technologies laboratory has developed a portable vehicle exhaust emissions testing system that enables manufacturers to report real-world driving emissions.
2016-02-02
Article
EngineLab’s EL129 control units for engine simulation and testing have a range of input and output options and can be adapted for flexible control system development.
Viewing 211 to 240 of 9372

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