6926475961

Key Words: Wheais, Railwey wheais, Noise generation

Th# mechanism of specrfic squaal fraquency was invastigated u ling an apparatus consisting of a Steel rod and a thin Steel diak. Squaais of higher modas occur in large rods. Squeal is ganaratad at specific contact posłtions on a rod. From the theoretical results, it was found that a squaal of tha frequen-cy naar tha contact frequency of the rod and ditk occurs.

display. Tha first moda is a real-tkne moda that dispiays only gross blade characteristics, such as maximum deflec-tions and standing waves. This modę is usad to aid tha operator in determining when to colfect detailad blade vibra-tion data. The second modę of operation isa post-Processing modę that will animate the actual blade yibrations using the detailad data collected on an aarlier data collection run. The operator cen wary the rata of peyback to view differing characteristics of blade yibrations.

84-1651

Study on the Mechanim of Noise Generation of R*iw«y Wheel and Ita Countermeaaure (5th Report, Flexural Yibratjon and Noiae of a Spoke Type Whed)

H. Matsuhisa. T. Hasegawa.and S. Sato Kyoto Univ., Sakyo-ku. Kyoto, Japan, Buli. JSME, 27 (224), pp 295-300 (Feb 1984) 14 figs, 3 tables, 7 refs

Kay Words: Wheais. Railway wheais, Noise generation, Flexural vibration

Tha noise of a train running over sharp curves is mainly ca u sad by flexural vibration of the wheels. Characteristics of the noise radiation of the spoke type wheel is experi-memally investigeted, and it is found that the noise gen-aratad by «>oke type wheai is consłderebly less than that of tha wab type wheel. In this anaiysis the wheei is assumad to baan annular Mindlin piąte which is elastically supported by springi which simulate tha spokes.

84-1653

Investigation of the Effect of Blade Sweep on Rotor Vibratory Loads

F.J. Tarzanin, Jr. and R.R. Vlaminck

Boeing Vertol Co.. Philadelphia. PA, Rept. No.

NASA-CR-166526, 134 pp (Oct 1983)

AD-A135 603

Key Words: Propeller blades, Helicoptars, Geometrie effects, Vibratory stresses

The effect of helicopter rotor blada planform swaap on rotor yibratory hub, blade, and control system loads has been analytically investigatad. The importance of swaap angla, sweep initiation radius, flap bending stiffness and torsion bending stiffness is discussad. The mechanism by which sweep influences the yibratory hub loads is inyestigated.

BLADES

(AIsoseeNos. 1564. 1861)

84-1652

Graphics Subsystem Retrofit Design for the Bladed-Diak Data Acquintion System

R.R. Carney

NASA Lewis Res. Ctr., Cleveland, OH, Rept. No. E-1760. NASA-TM-83510. 74 pp (Jan 1983) N84-12730

Kay Words: Blades, Pr opel lar blades, Vibratk>n recording, Data racorders, Graphic methods

A graphics subsystem retrofit design for tha turbojet biada yferation data acquisłtk>n system is prasantad. Tha graphics subtystem will oparata in two modas permłtting tha system operator to vlew blada yibrations on an oscilloscopa typa of

84-1654

Time Dorna in Anaiysis of a Rigid Two-Bladed Fully Gimbalied Helicopter Rotor with Circulatśon Control

P.S. Montana

David W. Taylor Naval Ship Res. and Dev. Ctr.. Bethesda, MD. Rept. No. DTNSRDC-83/081. AERO-1282, 88 pp (Dec 1983)

AD-A136 947

Key Words: Propeller blades, Helicoptars, Time domain method

An analytic investigetion was mada to dat er min* tha dynamie properties of a two-bladed rigid fully gimbalied helicopter rotor incorporating circulation control airfoils and tip jat propulsion. A time domain anaiysis was developad which provided the capabilłty of using nonlinear airfoil aerody-nsmica and arbitrary rotor physical characteristics. The effects of feather Principal axisof inertia location, horizontal gust disturbances, and feadback control on rotor stabilłty wara assessad.