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84-1828

Um| Modal Anałyus to IroproYc Confidence in Poute Element Aniłyu

M. Good and D. Macioce

Structural Measurement Systems, Inc., San Jose, CA. SA/. Sound Vib., JN3 (1). pp 18-22 (Jan 1984) 6 figs, 6 tables, 5 refs

Kay Word*: Modal analysis, Experimental modal analysis, Finit# alamant tachnkjue

A mathod i* demonstrated for improving the corralation of dynamie anaiyii* results from modal tasting and finita alamant analyai*. The mathod i* baaad on a parturbation of tha joint properties of tha structura within tha finłta element modal and maximizing a calcu lat ed corralation coefficient bat w aa n tha two *et« of aiganvaluat and eigenyectors.

to know tha individual transductances of tha accalaromatar and force transducer. If tha ratio of tha transductances i* known, it can ba utad to convert dimcntionlats fraqu*ncy response maasuramant* directly into enginaaring units without requiring intarmediate computations of accalaration and forca. Thi*articla deseribas ratio calibration,a genaratrva calibration proces* for measuring tha transductance ratio function for an accalarometer/forca transducer pair. It i* a simpla test that can ba performed during equipment setup for a structural dynamie* test.

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84-1829

Dual Correiated Random Excitatk>n Technkjue for Modal Terting

M. Sano, T. Kai, and K. Komatsu

National Aerospace Lab., Tokyo, Japan. Rept. No.

NAL/TR-762.13 pp (1983)

PB84-138072 (In Japanese)

Key Word*: E x par im anta I modal anaiyii*. Random axcitation

A dual correiated random cxcitation tachniqu* i* prasantad for eatimating tha modal parametar* of tymmccrlc ftructurei. In thia procedura, a pura random tignal i* u*ad to drive aach of two identical axcKation system* tocatad at symmetric posłtions of tha structura in order to raduca tha numtoer of dagraas of fraadom in a głvan maasuramant by sapa rat i ng symmatric and anti-symmatric vibration moda*.

84 1831

Determination of Tranamiaaion Lose, Acoustic Vełoc»ty, Surface Yelocity and Radia tion Efficiency by Uae of Two Microphone Techiuques

B.H. Forssen

Ph.D. Thesis. Purdue Univ., 226 pp (1983) DA8400354

Kay Word*: Panel*. Sound tran*mis*ion los*, Two microphone technique

This thasi* is concerned with tha davek>pmant of novel maasuramant approachas to estimata surface yelocity, radia-tion efficiency and transmission k>»* of panel structura*. Thesa approachas ara ba sad on the estimata* of tha auto and cross «>ectral densities of tha sound pressuras mas tu red by two ciosały spaced microphone*. Some of thesa approachas inyohre tha u te of tha recently davek>pad two microphone acoustic intensłty technique. which is reviawad extensively.

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84-1830

Ratio Calibration - the Right Choiee for Modal Auły*

D. Corelli

Quixote Measurement Dynamics, Inc., Cincinnati, OH. S/V. Sound Vib., 18.(1), pp 27-30 (Jan 1984) 7 figs

Key Word*: Exparimantal modal analytit

In order to gat callbratad mar tance frequency raaponaa maasuramant* for modal analysis test*, it i* not nacasaary

84-1832

Temperaturo Derivative8 of Elaatic Stiffneaaes De-rived from the Frequ en cy-Tempera turę Behavior of Quartz PI a te s

P.C.Y. Lee and Y.K. Yong

Dept. of Civil Engrg., Princeton Univ.. NJ, Proc. of Annual Symp. on Frequency Control (37th), June 1-3, 1983, Marriott Hotel, Philadełphia, PA. pp 200-207 (AD-A136 673)

AD-P002 477

Kay Word*: Temperatura affaets. Platas, Quartr ery steli

Linear field aquations for smali vtoratk>nt tu par posad on thermally inducad deformations by staady and uniform temperatura c hang et are derived from tha nonlinear field equattons of thermoalasticity in Lagrangian formulation. From the Solutions of thesa equations for tha thicknets-

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