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Technical Paper
2014-09-28
Yannick Desplanques
The ratio of two forces acting respectively perpendicular and normal to a contact surface of two bodies, the so-called "coefficient of friction", is widely used in engineering and science depicting the friction resistance of materials sliding over one another under given conditions. In spite of this dimensionless quantity appears to be convenient for engineering and relatively easy to determine, the use of tabulated friction coefficients becomes somewhat an issue to predict friction behavior of mechanical systems. The system dependence of friction is sometimes ignored, leading to misapplication. Moreover, the fundamental origins of sliding resistance are not as clear and care should be taken when attributing to the friction coefficient a fundamental significance. This paper will review the results obtained on friction by Charles Augustin Coulomb and used for hundred of years [1]. Firstly enunciated in Leonardo da Vinci manuscripts [2], the proportionality of the friction force to the applied load and its independency of the apparent area of contact were noticed from experiences and proposed for generalization by Guillaume Amontons in 1699, known as the two-first friction laws [3].
Technical Paper
2014-09-28
Jung Hoon Woo, Jeongkyu Kim, Kwang Yun Kim, Daekyung Ko
Creep groan noise occurs in a stopped vehicle by the simultaneous application of torque to the wheel and the gradual release of brake pressure in-vehicle. It is the low frequency noise and giving the driver a very uncomfortable feeling. It is caused by the stick-sleep effect at the lining and disc interface. Recently, the field claim of low frequency creep groan has increased. And there is a lot of efforts to creep groan noise by means of modification of lining material. On this paper, Transfer path of creep goan noise was analyzed through ODS and TPA. Additionally the correlation between Source (Brake torque variation, Brake vibration) and Creep Groan Sound level wasdiscussed. Finally countermeasure to Creep Groan noise was suggested.
Technical Paper
2014-09-28
Nils Gräbner, Merten Tiedemann, Utz Von Wagner, Norbert Hoffmann
Experts from industry and academia agree that brake squeal is an entirely nonlinear phenomenon. Consequently, using linear finite-element (FE) models and assessing the tendency of a brake system to squeal on the stability of the trivial solution is not appropriate. However, the latter approach - in the brake community known as complex eigenvalue analysis (CEA) - is extensively used in industry. Until now, nonlinear simulation approaches considering existence and stability of periodic solutions are limited to minimal models. Among the variety of reasons for this the complexity of large-scale nonlinear models as well as the identification of nonlinear material and system parameters are crucial. This contribution discusses the relevance of nonlinearities in friction brake noise, vibration, harshness (NVH) and presents a novel simulation approach for brake squeal. On the basis of experimental results it is pointed out that the consideration of nonlinearities in simulation as well as new methods for numerical studies are necessary to cope with the system-inherent phenomena.
Technical Paper
2014-09-28
Taeho Jung, Jeongkyu Kim
This paper deals with grind noise in vehicles which is a low frequency vibration problem at 100~1kHz that appears in low brake pressures and extremely low speed where there is a transition from static to dynamic condition. Recently, the customer complaints have increased for grind and creep groan noise more than squeal noise. Low frequency brake noise is a combined effect of brake and suspension systems working with each other. The noise transmission path is also important. Experimental results are confirmed through ODS, Modal, TPA and 3D acoustic camera for noise transmission path. Finally, reduction methods of grind noise are presented.
Technical Paper
2014-09-28
Kun Diao, Lijun Zhang, Dejian Meng
As a complicated phenomenon of friction-induced noise, brake frictional squeal has remained a challenge to automotive industry. So far, the generation mechanism of brake squeal has not been made clear, and the effective control measures have not been established. But the previous researchers found that the brake frictional squeal showed the time-varying characteristic obviously, but did not pay enough attention on it. In this paper, to avoid too many difficulties, which are caused by complex structures and numerous impact factors of brake system, a pin-on-disc system was established to study the generation mechanism and key impact factors of frictional squeal to investigate the time-varying characteristic of brake frictional squeal. In this paper, a series of tests on pin-on-disc system was carried out to study the time-varying frictional squeal. Through the frictional squeal rig test, brake frictional squeals were produced repetitively. During the rig test the frictional squeal, the contact forces and the acceleration of the pin end were sampled under various speed and loading force conditions, and the wavelet analysis, time-frequency analysis and feed-in energy calculation methods were used to investigate the time-varying characteristic of frictional squeal.
Technical Paper
2014-09-28
Katsuhiro Uchiyama, Yuji Shishido
Last year, we presented that “spring - mass model” FEA simulation from Stick-slip phenomenon standpoint for improvement of "creep groan” which is one of representative groan of brake system for automobile and carried out friction material’s Mu vs Velocity (M-V) property has high influence. This time, we would like to present our study of advantageous direction for reduction of creep groan with pad shape parameter (Chamfer and slot) by “Advanced spring – mass model” FEA simulation which developed into actual pad’s shape mass model.
Technical Paper
2014-09-16
Janice Meraglia, Mitchell Miller
As part of a comprehensive counterfeit mitigation effort, the Defense Logistics Agency (DLA) has created a program of four initiatives including the requirement of SigNature DNA marking on microcircuits. The Agency’s efforts began prior to the National Defense Authorization Act of Fiscal Year 2012, Section 818. Also, in the April 26, 2013 memo from Under Secretary Frank Kendall, the Office of Secretary of Defense is clearly focused on “prevention and early warning,” as the “primary” defense against counterfeits. SigNature DNA marking is within the spirit and guidance set forth by both DLA and OSD. Section 818 compels government action and creates real liability for contractors. Among other provisions, Section 818 requires the government and contractors to establish “…policies and procedures to eliminate counterfeit electronic parts from the defense supply chain” and “…mechanisms to enable traceability of parts.” SigNature® DNA provides per part forensic traceability and can be implemented as part of a comprehensive inventory management system.
Technical Paper
2014-09-16
Karl Strauss
“Today’s electronic components rely on principles of physics and science with no manufacturing precedence and little data on long term stability and reliability.” [1] Yet many are counting on their reliable performance years if not decades into the future, sometimes after being literally abandoned in barns or stored neatly in tightly sealed bags. What makes sense? To toss everything away, or use it as is and hope for the best? Surely there must be a middle ground! This paper discusses a three-phase initiative ultimately leading to the issuance of guidelines on the use of devices that have been subjected to long term storage, including recommended and required re-examinations based on Physics of Failure rather than fear and conjecture that is so prevalent today
Article
2014-08-18
Material laws and orientation information are coupled in a single finite element analysis to predict the performance of the hybrid composite beam under a dynamic three point bending load.
Article
2014-08-18
LC411-USBH low-profile compression load cells from Omega enable 1000 readings per second and feature a USB output to connect directly to a computer.
Article
2014-08-13
Model 3340 G-Logger three-channel, portable data acquisition system from Silicon Designs, Inc. (SDI) offers powerful Fast Fourier Transform (FFT) analysis and display, as well as real-time acceleration and GPS data collection and viewing, all within the same compact package.
Standard
2014-08-13
Various SAE vehicle sound level measurement procedures require use of a sound level meter which meets the Type 1 or Type 2 requirements of ANSI S1.4-1983 (see 2.1.1.1), or an alternative system which can be proved to provide equivalent test data. The purpose of this SAE Recommended Practice is to provide a procedure for determining if a sound data acquisition system (SDAS) has electro-acoustical performance equivalent to such a meter. By assuring equivalent performance of the test instrumentation, the equivalence of test data is assured. Two general configurations of sound data acquisition systems will be encompassed (see Figure 1). The first configuration consists of instrument sections which perform as a sound level meter. The second configuration is a system which records data for later processing. The intent of this document is to establish guidelines which permit the test engineer to insure equivalence of sound data acquisition systems to a sound level meter. It requires that the test engineer have a working knowledge of the characteristics of the sound data being measured.
Article
2014-08-12
AC17 test reporting begins in 2015. Initially it "gifts" applicable CAFE A/C efficiency credits, but leads to mandatory use. Industry also looks to reduce A/C-induced EV range loss from solar loading using films, glass, pre-ventilation.
Article
2014-08-12
Johnson Controls has opened a new crash test facility at its automotive seating headquarters in Plymouth, MI. One of the highlights of the facility is a Seattle Safety ServoSled that allows the automotive supplier to offer what it claims is the most accurate, standardized safety testing of seats globally through collaboration with its other testing facilities located in Burscheid, Germany; Changchun and Shanghai, China; and Yokohama, Japan.
Article
2014-08-04
HBM Inc.’s new industrial measurement amplifier enables users to make precise, dynamic measurements of raw and filtered torque, frequency, pulse, speed, and angle of rotation.
Article
2014-08-04
The SAB 32 shield connection clip from Conta-Clip provides a quick, simple connection when cables require shielding from interference.
Article
2014-08-04
The R&S SMW200A high-end vector signal generator from Rohde & Schwarz supports frequencies up to 20 GHz.
Article
2014-08-04
Sonoscan’s AW322 200 automated system for ultrasonic inspection of MEMS wafers images and identifies internal gap-type defects down to 5µm in size.
Article
2014-08-04
The Model XLUS88 subminiature, bidirectional tension/compression load cell from tecsis LP operates from 150 g to 1000 lb.
Article
2014-07-30
The Electric Power Research Institute has announced a collaboration with 8 automakers and 15 utilities to develop and demonstrate an open grid integration platform for plug-in electric vehicles (PEVs).
Article
2014-07-29
To develop an electric powertrain with a minimum noise level and minimized whining it is necessary to have accurate CAE simulation and precise criteria to assess whining noise.
Article
2014-07-23
In development of an advanced test engine to demonstrate fuel-saving and emissions-reducing technologies, the EPA is using ANSYS FORTÉ CFD software, giving its engineers the ability to quickly and inexpensively make multiple design iterations.
Article
2014-07-16
Ram’s official move to adopt the SAE J2807 towing standard for validating all three (1500, 2500, and 3500) of its pickup weight classes raises the competitive bar for the industry's other pickup players. Meanwhile, Ford has engineered its latest F-450 with half the GCVW capability of a Class-8 tractor-trailer.
Article
2014-07-15
Opel recently broke ground on a €210 million expansion of its Rüsselsheim International Technical Development center (ITDC) that will be used to develop and test engines. The 36,000-m² (400,000-ft²) expansion will be completed in 2017.
Article
2014-07-15
Northrop Grumman Corp. broke ground on a new $20 million Maryland Space Assembly and Test (M-SAT) facility on its Baltimore campus adjacent to Baltimore Washington International Thurgood Marshall Airport.
Article
2014-07-15
VPT Inc. has added a comprehensive radiation laboratory and test services facility to its Chelmsford, MA, facility. The 5000-ft² VPT Rad facility, which will serve the radiation and related test needs of aerospace electronics manufacturers, provides specialized environments and equipment for evaluating electronics used in applications where ionizing radiation can degrade device performance.
Magazine
2014-07-10
Off-highway engines advance beyond Tier 4 With Tier 4 Final/Stage IV needs met, engine OEMs direct their focus and competitive energies toward optimizing competitive solutions. At the same time, they need to keep a weather eye out for future regulations, which many expect. Autonomous vehicle challenges span many fields Many of the challenges faced by military and commercial design teams are similar. Racket busters With a quiet cab at the top of many tractor buyers' wish lists, agricultural equipment manufacturers are pursuing every opportunity possible to shed decibels.
Article
2014-07-07
Recently, with increased vehicle safety requirements, vehicle manufacturers are installing cutting-edge testing equipment in their own crash test facilities.Chrysler Group LLC partnered with Messring Systembau GmbH to upgrade Chelsea Proving Grounds, the central testing facility in Chelsea, MI.
Standard
2014-07-01
This SAE Aerospace Information Report (AIR) provides Nuclear, Biological and Chemical (NBC) protection considerations for environmental control system (ECS) design. It is intended to familiarize the ECS designer with the subject in order to know what information will be required to do an ECS design where NBC protection is a requirement. This is not intended to be a thorough discussion of NBC protection. Such a document would be large and would be classified. Topics of NBC protection that are more pertinent to the ECS designer are discussed in more detail. Those of peripheral interest, but of which the ECS designer should be aware are briefly discussed. Only radiological aspects of nuclear blast are discussed. The term CBR (Chemical, Biological, and Radiological) has been used to contrast with NBC to indicate that only the radiological aspects of a nuclear blast are being discussed. This is actually a more accurate term to describe the subject of this paper, but NBC has become more widely used in the aircraft industry.
Article
2014-06-30
Camber Corp. signed an agreement with Texas A&M–Corpus Christi (TAMUCC) to be the lead systems and business integrator for the Lone Star Unmanned Aircraft Systems Center (LSUASC) Test Site. The LSUASC is one of six unmanned aircraft systems (UAS) test sites identified by the FAA.
Viewing 31 to 60 of 8653

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