Results 91 to 100 of about 94,319 (292)
MATEC Web of Conferences, 2018 This paper analyzes the effect of noise on support vector machine (SVM) based fault diagnosis of IM (IM). For this, a number of mechanical (bearing fault, unbalanced rotor, bowed rotor and misaligned rotor) and electrical faults (broken rotor bar, stator
Gangsar Purushottam, Tiwari Rajiv
doaj +1 more source
Acoustic measurements of a full-scale coaxial hingeless rotor helicopter [PDF]
Acoustic data were obtained during a full-scale test of the XH-59A Advancing Blade Concept Technology Demonstrator in the 40- by 80-Foot Wind Tunnel. The XH-59A is a research helicopter with two coaxial rotors and hingeless blades. Performance, vibration,
Mosher, M., Peterson, R. L.
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An Improved Air Film Model for Studying the Tilt Characteristics of Aerostatic Thrust Bearings
International Journal of Mechanical System Dynamics, EarlyView.ABSTRACT In this study, an improved mass‐spring model that treats the lubricating air film as distributed springs is proposed to calculate the static and dynamic angular stiffness of aerostatic thrust bearings. The proposed model refines the traditional mass‐spring model by introducing the spatially varying mechanical properties of the air film and the
Hui Zhuang, Jianguo Ding, Yu Chang
wiley +1 more source
Analytical study of the effects of wind tunnel turbulence on turbofan rotor noise [PDF]
The influence of tunnel turbulence on turbofan rotor noise was carried out to evaluate the effectiveness of the NASA Ames 40 by 80 foot tunnel in simulating flight levels of fan noise.
Gliebe, P. R., Kerschen, E. J.
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Polymer Composites, EarlyView.Acquisition, filtering and modeling by genetic programming (tree pattern) of the acoustic signal for fiber‐filled composites. ABSTRACT This study experimentally investigated the discrete phase contributions of fibers and entrapped air on the attenuation spectrum of a fiber‐filled thermoplastic composite and derives a mathematical expression for sound ...
Austin D. Bedrosian +3 more
wiley +1 more source
Xibei Gongye Daxue XuebaoThe numerical calculation model for the aero-acoustic analysis of a tilt rotor was established by combining the free wake method and the FW-H (Ffowcs Williams-Hawkings) equation.
YUAN Mingchuan +4 more
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Axial Spacing Effects on Rotor-Rotor Interaction Noise and Vibration in a Contra-Rotating Fan
International Journal of Aerospace Engineering, 2019 Because of the potential technical advantages, the contra-rotation technology has become a renewed interest in aviation and other applications. Contra-rotation increases efficiency in comparison with the single-rotor design, but this advantage is not ...
Hengxuan Luan +4 more
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Wind tunnel investigations of model rotor noise at low tip speeds [PDF]
Experimental and related analytical results on model rotor rotational and broadband noise obtained in the anechoic wind tunnel and rotor facility are summarized.
Aravamudan, K. S. +2 more
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Embedding Fiber Segment Interferometry for Localization of Defects in Composite Structures
Polymer Composites, EarlyView.Graphical representation of composite structures with embedded fiber optic sensors for structural health monitoring, enabling strain measurement and damage localization under mechanical loading. ABSTRACT In the area of structural health monitoring (SHM), embedding strain sensors into smart composites is a key strategy for detecting failures arising ...
Shiva Mohammadkarimi +3 more
wiley +1 more source
Quarterly Journal of the Royal Meteorological Society, EarlyView.A theory for the interaction between a boundary layer and a low mountain is used to provide estimates of the turbulent orographic form drag, upward‐propagating mountain gravity‐wave drag, and trapped lee‐wave drag (case shown in the figure). After reviewing briefly how these processes are represented in weather and climate models, we propose a ...
Francois Lott +2 more
wiley +1 more source