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2015-11-19
Article
It is possible to look at Audi’s new-generation aluminum/carbon fiber-constructed V10 R8 supercar in two ways: its entire technology comprises 50% of the latest R8 LMS (Le Mans Series) GT3 racecar; alternatively, the racecar comprises 50% of the road car. Oliver Jarvis, Audi’s motorsport team driver, provides insights to both cars.
2015-11-17
Technical Paper
2015-32-0747
Hiroko Oshima, Hilmi Bin Hela Ladin, Akihito Ito, Nobutaka Tsujiuchi, Takayuki Koizumi
This paper describes a measurement points' placement technique for the sound source identification using inverse acoustic analysis. In order to reduce noise in NVH problem for various kinds of machines including small size engine, it is necessary to identify the sound source. The inverse acoustic analysis is a technique that is effective for the sound source identification.[1,2] The inverse acoustic analysis identifies a surface vibration of an object by measuring the radiated sound and solving the inverse problem. Nakano et al. researched about the location of sound pressure measurement points for accurate improvement.[3] They clarified that the sound pressure measurement points on the concentric circle gave more accurate surface vibration than the measurement points on the square lattice.
2015-11-17
Technical Paper
2015-32-0774
Hilmi Bin Hela Ladin, Nobutaka Tsujiuchi, Katsuhiko Kuroda, Akihito Ito
This paper describes the comparison method of input powers and contribution rates from vibration sources to a small power generator's enclosure represented by a thin-walled plane structure determined by Statistical Energy Analysis (SEA) and Transfer Path Analysis (TPA). In the pursuit of efficient ways to analyze the design dynamics of small machines such as a small power generator, it is important to identify information and dynamics of input power sources during machine operation. SEA and TPA are two of the most efficient methods in identifying the dynamics of a structure during machine operation. SEA is used for systems with many resonant modes, and predicted results are based on space averages. On the other hand, TPA is based on estimation of a frequency response function between an excitation point and a response point. In this study, we proposed a method to compare SEA evaluated by power injection method and TPA evaluated by matrix inversion method.
2015-11-17
Technical Paper
2015-32-0727
Akiyuki Yamasaki, Teruaki Yamamoto, Kazumasa Hisada, Hiroshi Nakahara, Takumi Kawasaki
This paper describes an engine mount system that achieves reduced vibration on an industrial type utility vehicle. First the vibration level and direction of the inline three cylinder engine installed in the vehicle was analyzed and based on these results a mount layout that leads to a reduced level of vibration felt by the passengers was developed. Next, this was applied on an actual vehicle and spring characteristics were designed for each mount. The actual spring constants were set such that when considering the engine to be a rigid body, the resonance frequency thereof occurs at an engine speed lower than idle and in addition were set to ensure component strength relative to driving forces and inertial forces that act while the utility vehicle is being driven. Lastly, achievement of significant vibration reduction was confirmed on an actual vehicle showing that this engine mount system is effective at reducing vibration.
2015-11-17
Journal Article
2015-32-0739
Hiroshi Kuribara, Hiroshi Horikawa, Takashi Teraguchi, Takanori Nagata, Daisuke Kitamura
A method applicable in the design stage to predict fatigue strength of a motorcycle exhaust system was developed. In this prediction method, a vibrating stress, thermal stresses, stresses resulting from the assembling of the exhaust system components and a deterioration of fatigue strength of materials originated from high temperature were simultaneously taken into account. For the prediction of the vibrating stress, flexible multibody dynamics was applied to get modeling accuracy for vibration characteristics of the entire motorcycle and the exciting force delivered from engine vibrations. The thermal conduction analysis and the thermal deformation analysis based on finite element method (FEM) were applied for the prediction of thermal stresses in the exhaust system components. The temperature distribution on the surfaces of the exhaust system components is required for calculations of the thermal stresses.
2015-11-11
Article
Traffic fatalities have declined significantly over the last several years, but the U.S. is on track to have its deadliest year since 2007, according to the National Safety Council. That’s shining the spotlight on crash testing, according to industry experts in a Technical Webinar Series from the Editors of SAE.
2015-11-11
Article
The new $30 million facility at the Warren Technical Center uses a belt-type moving ground plane to simulate full driving conditions on clay models up to an indicated 155 mph (250 km/h).
2015-11-10
Standard
J2805_201511
This SAE Standard is equivalent to ISO 362-1:2015 and specifies an engineering method for measuring the noise emitted by road vehicles of categories M and N under typical urban traffic conditions. It excludes vehicles of category L1, L2, L3, L4, and L5. The specifications are intended to reproduce the level of noise generated by the principal noise sources during normal driving in urban traffic. The method is designed to meet the requirements of simplicity as far as they are consistent with reproducibility of results under the operating conditions of the vehicle. The test method requires an acoustical environment that is obtained only in an extensive open space.
2015-11-10
Standard
J2889/1_201511
This SAE Standard is derived from SAE J2805 and specifies an engineering method for measuring the sound emitted by M and N category road vehicles at standstill and low speed operating conditions.. The specifications reproduce the level of sound which is generated by the principal vehicle sound sources consistent with stationary and low speed vehicle operating conditions relevant for pedestrian safety. The method is designed to meet the requirements of simplicity as far as they are consistent with reproducibility of results under the operating conditions of the vehicle. The test method requires an acoustic environment which is only obtained in an extensive open space or in special designed indoor facilities replicating the conditions of an extensive open space. Such conditions usually exist during: • Measurements of vehicles for regulatory certification. • Measurements at the manufacturing stage. • Measurements at official testing stations.
2015-11-09
Article
Design and build time of the UAV is said to be reduced 50%, and its is use of lightweight materials the enabler to reaching speeds over 150 mph.
2015-11-08
Article
AFRL is on the lookout for environmentally safer inorganic coatings solutions that will help protect and extend the life of aluminum landing gear.
2015-11-08
Article
The company continues to commit and breathe new life into its 40-year old fourth-generation fighter aircraft.
2015-11-08
Article
The PW1900G engine model for Embraer's E190-E2 recently flew on P&W's 747SP flying test bed at the company's Mirabel Flight Test Center in Quebec, with the engine family sited as a 'climate solution.'
2015-11-03
Magazine
Active in aero Several automakers-notably Mercedes-Benz and Audi - used the Frankfurt Motor Show stage to reveal sleek vehicles that aggressively employ active aerodynamic elements and other advances to reduce drag. Composites permeate inside and out Composite materials are gaining popularity for both unseen structural components and for exterior eye candy. Powertrain testing: coping with complexity With increasing use of electrical components to extend the performance of conventional combustion engines, powertrain development has never been more complicated. The good news is that test and development engineers are harnessing advanced simulation techniques and computer processing to develop the most efficient and fun powertrains ever. Can ads help in vehicle-to-vehicle rollout? Porsche unveils new downsized, boosted 3.0-L boxer six. Johnson Controls, Faurecia envision interiors for autonomous driving. Jaguar enters performance crossover SUV segment.
2015-11-02
Article
Additional in-house testing capabilities and the hiring of 180 engineers and technicians underscores an ambitious strategy to reach $15B in annual sales by 2020.
2015-10-28
Article
Skogforsk (the Forestry Research Institute of Sweden) has funded a KTH research initiative intended to help improve the suspension of forestry machines with the goal of achieving significant productivity improvements. KTH’s mission is to streamline the design process by validating the capability to simulate the operation of forestry machines under real-world operating conditions.
2015-10-26
Article
Just as engineers of consumer vehicles are being asked to shorten development cycles and improve performance, reliability, and safety, so are developers of off-highway vehicles, such as construction equipment and agricultural machinery.
2015-10-03
Article
Technologies considered necessary for unmanned aircraft systems (UAS) to safely avoid other aircraft while moving through airspace recently were put to the test using NASA's remotely piloted Ikhana aircraft.
2015-10-02
WIP Standard
J3111
The scope of this recommended practice is to establish definitions and recommended methods for the measurement of lateral run-out and disc thickness variation in the laboratory and vehicle for passenger cars and light duty trucks up to 4546 kg gross vehicle weight. This recommended practice will breakdown the instrumentation (sensors and sizes), test setup, and data processing.
2015-09-29
Technical Paper
2015-01-2854
Timothy Opperwall, Andrea Vacca
Abstract This work contributes to the overall goal of identifying and reducing noise sources and propagation in hydraulic systems. This is a general problem and a primary design concern for all fluid power applications. The need for new methods for identification of noise sources and transmission is evident in order to direct future modeling and experimental efforts aimed at reducing noise emissions of current fluid power machines. In this paper, this goal is accomplished through the formulation of noise functions used to identify contributions and transfer paths from different components of the system. An experimental method for noise transfer path analysis was developed and tested on a simple hydraulic system composed of a reference external gear pump, attached lines, and loading valve. Pressure oscillations in the working fluid are measured at the outlet of the pump. Surface vibrations are measured at multiple locations on the pump and connected system.
2015-09-29
Technical Paper
2015-01-2871
Mounika Katragadda, Kalyan Deepak Kolla, Venkata Suresh Yaparala
Abstract In the automotive industry many components face fatigue failure due to prolonged vibrations. This is commonly known as Vibration Induced Fatigue (VIF). There are two approaches to evaluate this; time & frequency domain. A straight forward and widely used method is the rainflow counting technique in the time domain. This counting algorithm is readily available and, apart from the time history, it needs only one variable input (the number of stress ranges). In case of high cycle fatigue, longer time histories are required for a statistically representative fatigue estimate, which makes the time domain approach consume large amounts of time and resources. This shifts our interest towards frequency domain methods. In the frequency domain, Dirlik's method is proven to be robust and gives closer results to the time domain.
2015-09-29
Technical Paper
2015-01-2781
Rohit Saha, Yonghong Liu, Mahesh Madurai Kumar, Bill Kendrick, Long-Kung Hwang, Liyun Lucas, Dinh Ngo
Abstract This paper demonstrates the use of a system level model that includes torsional models of a Cummins diesel engine and an Allison transmission to study and improve system NVH behavior. The study is a case where the two suppliers of key powertrain components, Cummins Inc. and Allison Transmission Inc., have collaborated to solve an observed NVH problem for a vehicle customer. A common commercial tool, Siemens' AMESim, was used to develop the drivetrain torsional system model. This paper describes a method of modelling and calibration of baseline engine and transmission models to identify the source of vibration. Natural frequencies, modal shapes, and forced response were calculated for each vehicle drive gear ratio to study the torsional vibration. Several parametric studies such as damping, inertia, and stiffness were carried out to understand their impact on torsional vibration of the system.
2015-09-29
Technical Paper
2015-01-2856
Hongbin Wang, Ojas Patil, QingHui Yuan, Aaron Hertzel Jagoda
EXTENDED ABSTRACT Fuel economy of both highway and off-highway vehicles is a major driver for new technology development. One of the technologies to meet this driver is a digital valve based hydraulic system. Digital Hydraulics technology employs high speed on/off valves to achieve the same functionality with no throttling loss. Furthermore, by forming various architecture by using digital valves, it provides the system level capability and flexibility for energy saving and productivity improvement. There are many challenges in fully realizing the full efficiency benefits of the system in an actual application. These challenges include packaging, durability, a change in the operator's perception of the vehicle as well as hydraulic system performances during operation. One significant issue is the noise, vibration and harshness (NVH) of the system. Due to the nature of the digital valve operation, there are severe transient dynamics in the fluid system.
2015-09-27
Technical Paper
2015-01-2684
Seongjoo Lee, ShinWook Kim, ShinWan Kim, Seong Rhee
Rear disc brake squeal test results confirm the disc wear - brake squeal correlation reported earlier on front disc brakes. A significant amount of Fe transferred from the disc to the NAO pad surface is detected and the distribution of the transferred Fe is very non-uniform on the pad surface. The pad surface formulation reaches that of Low-Steel Lomets. Disc pads from a noisier brake retain more transferred particles than from a less noisy brake. The pad surface retains more transferred Fe after noise test procedures than after performance test procedures. The transferred Fe particles are either barely visible or invisible. During brake noise test procedures, discs wear in weight as much as disc pads. No correlation is found between average in-stop Mu, maximum in-stop Mu or in-stop delta Mu and brake squeal.
2015-09-27
Technical Paper
2015-01-2686
Enrique Wegmann, Achim Dohle
Abstract The NVH behavior of brake systems remains a core problem for the brake industry. Many efforts have been made to achieve a better system understanding, but the prediction of noise occurrence based on measurable parameters remains unsatisfactory. By considering the brake pad as one key component within the brake system, until today different measurement methods describing its material properties have been developed. This work analyses the correlation of all important “state of the art” friction material/pad parameter measurement methods to the NVH behavior of a specific brake system on a statistical basis. The answer to the question “does the NVH parameter for friction materials exist” ? will be derived from these correlation results.
2015-09-27
Technical Paper
2015-01-2688
Hayuru Inoue, Kumi Hashimoto, Yoichi Kumemura
Abstract It is well known that improving NV performance and weight saving are reciprocity. Brake squeal free is one of the top priority issues during development of brake system. To date, complex eigenvalue analysis has been utilized for prediction of brake squeal. It solves the structural instability problems by modal coupling which is the phenomenon that natural frequencies of normal modes are quite consistent. The positive real parts of complex eigenvalues are identified as instable vibration which causes brake squeal. On the other hand, the needs for light-weight brake system are higher than before due to recent trends of economizing fuel consumption and high driving performance. In order to obtain coexistence of brake squeal free with weight saving, shape optimization technique has been proposed for complex eigenvalue analysis.
2015-09-27
Technical Paper
2015-01-2687
Aditya Kant Choudhary, Yogesh Mense, Saurabh Singh, Mahesh Shridhare
Abstract Brake noise is one of the common complaints and an irritant not just for the vehicle occupants but equally for the passers-by. Brake noise is actually vibration that is occurring at a frequency that is audible to the human ear. This occurrence of brake noise like brake squeal (>1 kHz) and groan (<1 kHz) is often very intense and can lead to vehicle complaints. During a brake noise event, vehicle basic structure and suspension system components are excited due to brake system vibration and result in a resonance that is perceived in the form of a noise. Proposed work discusses an experimental study that is carried out on a vehicle for addressing concern regarding disc brake squeal and groan noise. Based on the preliminary inputs, vehicle level study was carried out in order to simulate the problem and objectively capture its severity.
2015-09-27
Technical Paper
2015-01-2689
Katsuhiro Uchiyama, Yuji Shishido
Abstract Brake groan analysis and improvement is progressing based on experimental measurements. An advanced brake assembly FEA model was built which considers torsional stiffness of suspension for analyzing creep groan. Creep groan is a representative groan noise of brake system from stick-slip phenomenon standpoint. This year we will present our study for advantageous direction for reduction of creep groan which will focus on friction material µ vs. Velocity (µ-V) property, friction material physical properties and relative velocity between brake pads and rotor by advanced brake assembly FEA model.
2015-09-27
Technical Paper
2015-01-2702
Chihoon Jo, Jaeseung Cheon, Jongsung Kim, Yongsik Kwon
Abstract EMB (Electro-Mechanical Brake) which converts electrical motor power to brake clamping force at each wheel is a system that has been investigated and developed by various automotive part suppliers through the years. In particular, as the number of electrically powered vehicles, such as hybrid electric vehicles, electric vehicles and fuel cell electric vehicles, has expanded, the EMB has received increased interest due to its fast response that is much suited for effective cooperative control with regenerative braking. However, issues such as cost competitiveness, reliability and regulations need to be solved for commercialization [1-2]. A new concept, the hybrid Electro-Mechanical Brake (hEMB) is characterized by a dual piston structure linked by hydraulics inside of the caliper. It is possible to reduce the required motor power and increase the level of emergency back-up braking through the amplification effect of the dual piston mechanism [3].
2015-09-27
Technical Paper
2015-01-2690
Joo Sang Park
Abstract There are three kinds of noise mechanisms which are stick-slip, self-excited vibration and unstable dynamic behavior. This study is of a pad unstable behavior caused by pad spring contact stiffness and weak forces and improving a lower squeal noise due to self-excited vibration in brake system. This paper discusses a theoretical approach, numerical and experimental test to understand the squeal mechanism for unstable pad behavior and the analysis and measurement of mode coupling between brake components to decrease noise propensity. Three different approach are considered to understand noise mechanism. Fundamental approach is more important than experimental modal analysis, CEA (Complex Eigen value Analysis) because the minimal vibration analysis is principle approach which has been proved by many researchers. CEA and modal test is useful to study the relationship between lower squeal noise and self-excited vibration for more details.
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