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Viewing 1 to 30 of 21733
2017-06-05
Technical Paper
2017-01-1820
Martin Sopouch, Josip Hozmec, Alessandro Cadario
This paper presents a simulation environment and methodology for noise and vibration analyses of a driven rear axle in a bus application, with particular focus on medium to high frequency range (400 Hz to 3 kHz). The workflow demonstrates structure borne noise and sound radiation analyses. The fully flexible Multi–Body Dynamics (MBD) model - serving to cover the actual mechanical excitation mechanisms and the structural domain – includes geometrical contacts of hypoid gear in the central gear and planetary gear integrated at hubs, considering non-linear meshing stiffness. Contribution of aforementioned gear stages, as well as the propeller shaft universal joint at the pinion axle, on overall axle noise levels is investigated by means of sensitivity analysis. Based on the surface velocities computed at the vibrating axle-housing structure the Wave Based Technique (WBT) is employed to solve the airborne noise problem and predict the radiated sound.
2017-06-05
Technical Paper
2017-01-1809
Dhanesh Purekar
Engine noise is considered significant aspect of product quality for light and medium duty diesel engine market applications. Gear whine is one of those noise issues which is considered objectionable and impacts the customer perception. Gear whine could results due to defects in the gear manufacturing process and/or due to inaccurate design of the gear macro and micro-geometry. The focus of this technical paper is to discuss gear whine considerations from the production plant perspective. A gear whine case study is presented on the data collected on one of the Cummins diesel engines in the production environment. This paper also includes quick overview of measurement process, test cell environment, noise acceptance criteria considerations. This paper highlights the benefits of using production facility for developing next generation of product development from whine perspective.
2017-06-05
Technical Paper
2017-01-1839
Edward T. Lee
It is common for automotive manufacturers and off-highway machinery manufacturers to gain an insight of the system structural dynamics by evaluating the system inertance functions near the mount locations. The acoustic response at the operator’s ears is a function of the vibro-acoustic characteristics of the system structural dynamics interacting with the cavity, with the actual load applied at the mount locations. The overall vibro-acoustic characteristics can be influenced by the change in local stiffness. To analyze the response of a system, it is necessary to go beyond analyzing its transfer functions. The actual load needs to be understood and be applied towards the transfer function set. Finite element (FE) based analysis provides a good foundation for deterministic solutions. However finite element method suffers in accuracy as the frequency increases. Many NVH problems happen to be at the mid frequency range where solving the problem with the FE-only approach falls short.
2017-06-05
Technical Paper
2017-01-1823
Dennis J. Kinchen
Powertrain mounting systems design and development involves creating and optimizing a solution using specific mount rates and multiple operating conditions. These mount rates become the recommended “nominal” rates in the specifications. As is typical of natural materials, the properties have variation resulting in a tolerance around the nominal specification which leads to differences in noise and vibration performance. A system that is robust to this variation is desired. The design and development process requires evaluation of these mounts to ensure that the noise and vibration performance is consistently met. During the hardware development of the powertrain mounting system a library of mounts that include the range of production variation is studied however this is time consuming. In this paper, a methodology is described to reduce the hardware evaluation time and provide a recommended optimal solution that is robust in the presence of production mount property variation.
2017-06-05
Technical Paper
2017-01-1760
Weimin Thor, J. Stuart Bolton
Due the increasing concern with the acoustic environment within an automotive vehicle, there is an interest in measuring the acoustic properties of automotive door seals. These systems play an important role in blocking external noise sources, such as aerodynamic noise and tire noise, from entering the passenger compartment. Thus, it is important to be able to conveniently measure their acoustic performance. Previous methods of measuring the ability of seals to block sound required the use of either a reverberation chamber or a wind tunnel with a special purpose chamber attached to it. That is, these methods required the use of large and expensive facilities. A simpler and more economical desktop procedure is thus needed to allow easy and fast acoustic measurement of automotive door seals.
2017-06-05
Technical Paper
2017-01-1907
Yang Wang, Yong Xu, Xiao Tan
OPTIMIZATION OF THE POWERTRAIN MOUNTING SYSTEM VIA DOE METHOD Authors: Wang Yang*, Wang Hui*, Xu Yong* * NVH Section, Brilliance-Auto Engineering Research Institute, Shenyang, China, 110141 Key Words: NVH; DOE; Powertrain Mounting System; Analysis of Variance Research and/or Engineering Questions/Objective The vibration isolation performance of vehicle powertrain mounting system is mostly determined by the three-directional stiffnesses of each mount block. Because of the manufacturing tolerance and the coupling effect, the stiffnesses of mounts cannot be maintained stable. The purpose of this study was to find out the way to optimize the stiffnesses of mounts via the design of experiments (DOE). Methodology According to the DOE process, a full factorial design was implemented. The z-direction stiffnesses of three mount blocks in the mounting system were selected as the three analysis factors.
2017-06-05
Technical Paper
2017-01-1818
Ramya Teja, T. R. Milind, Rodney C. Glover, Sunil Sonawane
Helical gears are used more commonly than spur gears due to their higher load carrying capacity, efficiency and lower noise. Helical gear pairs consist of base and axial planes in the plane of action. Transmission Error (TE) is considered as a dominant source of gear whine noise so gears pairs are analyzed and designed for lower TE. In process of designing helical gears for lower TE, the shuttling moment can be a significant excitation source. A shuttling moment is caused by the shifting of the centroid of the tooth normal force back and forth across the lead. Shuttling force is produced by a combination of design parameters, misalignment and manufacturing errors. Limited details are available on this excitation and its effect on overall noise radiated from the gear box or transmission at is gear mesh frequency and harmonics. LDP provides shuttling force as a bearing force in the base plane direction at one edge of the face width only.
2017-06-05
Journal Article
2017-01-1767
Zhenghong Shi, Teik Lim
Nonlinear interaction between time-varying hypoid gear mesh and bearing support is investigated in this study. Mesh parameters are time-varying due to complex tooth profile of hypoid gear. Bearing stiffness is formulated based on real geometry and instantaneous orbital position of rolling elements. Linear model is firstly analyzed to study the modal frequency and mode shape variations under different stiffness ratio between gear mesh and bearing support. Then, nonlinear analysis is conducted to compare the differences between linear and nonlinear dynamic response based on specific nonlinear conditions of geared rotor system. It is found that the coupling between hypoid gear mesh and bearing support can be either strong or weak depending on the ratio between mesh stiffness along line-of-action (LOA) and bearing stiffness in radial direction. Parametric studies indicate that dynamic mesh force is sensitive to bearing clearance for certain stiffness ratio.
2017-06-05
Journal Article
2017-01-1776
Mohsen Kolivand, Glen Steyer, Clifford Krieger, Max-Ferdinand Stroh
Hypoid gears transmission error (TE) is a metric that is usually used to evaluate their NVH performance in component level. The test is usually done at nominal position as well as out of positions where the pinion and gear are moved along their own axis and also along offset direction to evaluate sensitivity of the measured TE to positional errors. Such practice is crucial in practical applications where the gear sets are inevitably exposed to off position conditions due to a) housing machining and building errors, b) deflections of housing, bearings, etc under load and c) thermal expansions or contractions of housing due to ambient temperature variations. From initial design to development stage, efforts should be made to design the gear sets to be robust enough to all combinations of misalignments emanated from all three mentioned categories.
2017-06-05
Journal Article
2017-01-1772
Yawen Wang, Xuan Li, Guan Qiao, Teik Lim
The prediction and control of gear vibration and noise has become very important in the design of a quiet, high-quality gearbox systems. The vibratory energy of the gear pair caused by transmission error excitation is transmitted structurally through shaft-bearing-housing assembly and radiates off from exterior housing surface. Most of the previous studies ignore the contribution of components flexibility to the transmission error. In this study, a system level model of axle system with hypoid gear pair is developed, aiming at investigating the effect of the elasticity of the shafts, bearings and housing. The load distribution results and gear transmission errors are calculated and compared between different assumptions on the boundary conditions. A series of parametric studies are also performed to analyze the effects of various shaft-bearing configurations and properties on the dynamic responses of the geared system.
2017-06-05
Journal Article
2017-01-1771
Mohamed El morsy, Gabriela Achtenova
Gear fault diagnosis is important in the vibration monitoring of any rotating machine. When a localized fault occurs in gears, the vibration signals always display non-stationary behavior. In early stage of gear failure, the gear mesh frequency (GMF) contains very little energy and is often overwhelmed by noise and higher-level macro-structural vibrations. An effective signal processing method would be necessary to remove such corrupting noise and interference. This paper presents the value of optimal wavelet function for early detection of faulty gear. The Envelope Detection (ED) and the Energy Operator are used for gear fault diagnosis as common techniques with and without the proposed optimal wavelet to verify the effectiveness of the optimal wavelet function. Kurtosis values are determined for the previous techniques as an indicator parameter for the ability of early gear fault detection. The comparative study is applied to real vibration signals.
2017-06-05
Journal Article
2017-01-1909
Joel Bruns, Jason Dreyer
The application of hydraulic body mounts between a pickup truck frame and cab to reduce freeway hop and smooth road shake has been documented in literature and realized in production vehicles. Previous studies have demonstrated the potential benefits of these devices, often through iterative prototype evaluation. Component dynamic characterization has also shown that these devices exhibit significant dependence on dynamic amplitude and preload; however, analysis of these devices has not fully addressed these dependences. This paper aims to understand the amplitude and preload dependence on the spectrally varying properties of a production hydraulic body mount. This double-pumping, three-spring mount construction has a shared compliant element between the two fluid-filled chambers. A reduced-order multi-physics model of the mount assembly is developed using parameters derived from bench testing of the different elastomeric components and the fluid system.
2017-06-05
Technical Paper
2017-01-1815
Pranab Saha, Satyajeet P. Deshpande
This paper discusses the importance of dissipative sound package system in the automotive industry and how it works. Although this is not a new technique at this stage, it is challenging to meet the subsystem target levels that were originally developed for parts based on barrier decoupler concept. This paper reviews the typical construction of a dissipative system and then emphasizes the importance of different layers of materials that are used in the construction, including what they can do and cannot do. The paper also discusses the importance of proper manufacturing of the part.
CURRENT
2017-04-27
Standard
J2743_201704
This SAE Recommended Practice is intended to describe a procedure for rating the size of single-stage reciprocating air compressors. It describes the conditions that can be used for testing and it defines a standardized rating expressed in SLPM (SCFM).
2017-04-27
WIP Standard
J2494/2
This SAE Standard covers general dimensional specifications for non-metallic body reusable push to connect tube fittings for use in the piping of air brake systems on automotive vehicles. This type of fitting is intended for use with nylon tubing per SAE J844. It is not intended to restrict or preclude other designs of a tube fitting for use with SAE J844. Performance requirements for SAE J844 are covered in SAE J1131. See SAE J2494-3 for the performance requirements of Reusable (push-to-connect) fittings intended for use in Automotive Air Brake Systems and U.S. Department of Transportation FMVSS 571.106.
2017-04-27
WIP Standard
J2494/1
This SAE Standard covers general and dimensional specifications for brass bodied reusable Push to Connect tube fittings for use in the piping of vehicular air brake systems. This type of fitting is intended for use with nylon tubing per SAE J844. See SAE J2494-3 for the Performance Requirements of Reusable (Push to Connect) Fittings Intended for Use in Automotive Air Brake Systems and U.S. Department of Transportation, National Highway Traffic Safety Administration (NHTSA) Federal Motor Vehicle Safety Standards (FMVSS) 571.
CURRENT
2017-04-27
Standard
AS1895/7E
SCOPE IS UNAVAILABLE.
2017-04-27
WIP Standard
J512
This SAE Standard covers complete general and dimensional specifications for the various types of tube fittings intended for general application in the automotive, appliance, and allied fields. See SAE J1131 for the performance requirements of reusable (push to connect) fittings intended for use in automotive air brake systems.
CURRENT
2017-04-26
Standard
AS7460C
This procurement specification covers aircraft-quality bolts and screws made of 6.0Al - 4.0V titanium alloy and of 160 ksi tensile strength at room temperature.
2017-04-24
WIP Standard
AMS6372N
This specification covers an aircraft-quality, low-alloy steel in the form of mechanical tubing. This tubing has been used typically for parts, 0.75 inch (19 mm) and under in section thickness at time of heat treatment, requiring a through-hardening steel capable of developing hardness as high as 40 HRC when properly hardened and tempered and for parts of greater thickness but requiring proportionately lower hardness, but usage is not limited to such applications.
CURRENT
2017-04-24
Standard
AS3411C
SCOPE IS UNAVAILABLE.
CURRENT
2017-04-24
Standard
AS18029B
SCOOPE IS UNAVAILABLE.
2017-04-21
WIP Standard
AS153J
Add integral silicone cuff max length and OD to flared parts standards
2017-04-21
WIP Standard
AS154H
Add integral silicone cuff max length and OD to flared parts standards
2017-04-21
WIP Standard
AS155H
Add integral silicone cuff max length and OD to flared parts standards
Viewing 1 to 30 of 21733

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