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Viewing 61 to 90 of 15761
2015-06-15
Technical Paper
2015-01-2212
A. Elsawaf, H. Metered, T. Vampola, Z. Sika
Abstract Active vibration control is the most effective method used for suppressing vibrations from external sources. This paper presents the particle swarm optimization (PSO) algorithm to search about the optimum feedback controller gains for the active mount suspension, for the first time, to reduce the vibrations level of a structural system. It consists of vibrating mass and flexible beam subjected to an external disturbance. A mathematical model and the equations of motion of the structure system with an active mount suspension are simulated using Matlab/Simulink software. The active controller was designed to control the first three modes of the structure. The proposed PSO algorithm aims to minimize the acceleration of the suspended mass as the objective function with constraint of the actuator force. Vibrations level is examined theoretically in order to assess the effectiveness of the proposed controller.
2015-06-15
Journal Article
2015-01-2229
Benjamin Joodi, Scott Allen Noll, Jason Dreyer, Rajendra Singh
Abstract Elastomeric joints are utilized in many automotive applications, and exhibit frequency and excitation amplitude dependent properties. Current methods commonly identify only the cross-point joint property using displacement excitation at stepped single frequencies. This process is often time consuming and is limited to measuring a single dynamic stiffness term of the joint stiffness matrix. This study focuses on developing tractable laboratory inverse experiments to identify frequency dependent stiffness matrices up to 1000 Hz. Direct measurements are performed on a commercial elastomer test system and an inverse experiment consisting of an elastic beam (with a square cross section) attached to a cylindrical elastomeric joint. Sources of error in the inverse methodology are thoroughly examined and explained through simulation which include ill-conditioning of matrices and the sensitivity to modeling error.
2015-06-15
Journal Article
2015-01-2227
Scott Allen Noll, Benjamin Joodi, Jason Dreyer, Rajendra Singh
Abstract Elastomeric joints such as mounts and suspension bushings undergo broadband excitation and are often characterized through a cross-point dynamic stiffness measurement; yet, at frequencies above 100 Hz for many elastomeric components, the cross- and driving-point dynamic stiffness results significantly deviate. An illustrative example is developed where two different sized mounts, constructed of the same material and are shaped to achieve the same static stiffness behavior, exhibit drastically different dynamic behavior. Physical insight is provided through the development of a reduced order single-degree-of-freedom model where an internal resonance is explained. Next, a method to extract the parameters for the reduced order model from a detailed finite element bushing model is provided.
2015-06-15
Technical Paper
2015-01-2225
Peng Yu, Tong Zhang, Jing Li, Shiyang Chen, Rong Guo
Abstract Faced on transient vibration of EV, considering the characteristics of the electric drive system, active and passive integrated transient vibration control method of power train mounting system was proposed. Models of power train system and mounting system were established, modal characteristics were grasped by simulation and experiment. A feed-forward controller was constructed from the facet of active control, mounting system transient vibration and power train torsion vibration were reduced. Based on this, further optimization of mounting system was conducted from a passive control perspective. Results show that the active and passive integrated control method can effectively reduce the dynamic reaction force of mounting points, improve the vibration conditions of power train and vehicle body as well.
2015-06-15
Technical Paper
2015-01-2352
Chaitanya Krishna Balla, Sudhakara Naidu, Milind Narayan Ambardekar
Abstract Noise Vibration and Harshness (NVH) refinement is one of the important parameters in modern vehicle development. In city traffic conditions, idling is an engine operating condition where a driver focuses attention more to his/her vehicle. Tactile vibration & noise levels inside the cab play an important role in all vehicles, especially those powered by diesel engines where combustion pressures are higher. They lead to discomfort & fatigue of passengers of even a low cost vehicle. Now its idle NVH is influenced mainly by vibration-isolation provided by power-train (PT) mounting design, This paper describes steps taken to improve the idle vibrations at a driver seat of a small commercial vehicle (SCV) with a 2-cylinder diesel engine of 800 cc through redesign of PT-mounting along with fine tuning of idle speed of the engine. A resonance was avoided between the first firing order at idling and PT rigid-body mode in pitching.
2015-06-12
Standard
AS28937A
SCOPE IS UNAVAILABLE.
2015-06-12
Standard
AMS5934/H1000
This specification covers a corrosion-resistant steel product in the solution and precipitation heat treated (H1000) condition 12 inches (305 mm) and under in nominal diameter, thickness or for hexagons, least distance between parallel sides (See 8.2).
2015-06-12
Standard
AS1301F
This SAE Aerospace Standard (AS) provides the essential minimum design, installation and removal standard for AS1299, AS1985, AS1986, AS4099, AS5368, and AS5986 adapters and is applicable when specified on engineering drawings or in procurement documents.
2015-06-12
WIP Standard
MA3428A
No scope available.
2015-06-12
WIP Standard
MA3394A
No scope available.
2015-06-12
WIP Standard
MA3393A
No scope available.
2015-06-12
WIP Standard
AS172236D
No scope available.
2015-06-10
WIP Standard
AMSR83412/1A
The purpose of this specification sheet is to set up a standardized part numbering system for o-rings procured to MIL-R-83412(USAF), type 1.
2015-06-09
Standard
AMS4944L
This specification covers a titanium alloy in the form of seamless tubing.
2015-06-08
Standard
AMS6499A
This specification covers a premium aircraft-quality, low-alloy steel in the form of bars, forgings, mechanical tubing, and forging stock.
2015-06-08
Standard
AMS6915B
This specification covers a titanium alloy in the form of bars up through 6.000 inches (152.40 mm) inclusive, in nominal diameter or least distance between parallel sides, forgings of thickness up through 6.000 inches (152.40 mm), inclusive and stock for forging of any size.
2015-06-05
Standard
AMSR83485/1A
The purpose of this specification sheet is to set up a standardized part numbering system for o-rings procured to MIL-R-83485 (USAF).
2015-06-04
Standard
AMS4465A
This specification covers an aluminum alloy in the form of sheet, clad on one side.
2015-06-04
WIP Standard
AS4726A
This specification establishes the requirements for self-locking nuts, wrenching type (i.e., hexagon, double hexagon, and spline drive), made of a corrosion and heat resistant steel of the type identified under the Unified Numbering System as UNS S66286. Classification: a. 220 ksi minimum tensile strength at room temperature and b. 850 degrees F maximum test temperature of parts. Primarily for use in aerospace propulsion systems in temperatures up to approximately 850 degrees were nuts are used with bolts capable of developing 220 ksi axial tensile strength at room temperature, and having UNJ thread form.
2015-06-04
WIP Standard
AS85049D
This specification covers connector accessories for use with electrical connectors, refer to 6.9.
Viewing 61 to 90 of 15761

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