Title

Modeling Techniques for Sonic Fatigue Prediction

Date

1966

Index Abstract

Coming Soon

Photo Quality

Complete

Report Number

AFFDL TR 65-171

Corporate Author

North American Aviation, Inc.

Laboratory

Air Force Flight Dynamics Laboratory

Extent

140

NTRL Accession Number

AD648078

Identifier

AD0648078

AD0648078

Access Rights

Distribution of this document is unlimited

Distribution Classification

1

Contract

AF 33(615)-1743

DoD Project

1471

DoD Task

147101

DTIC Record Exists

Yes

Distribution Change Authority Correspondence

None

Abstract

The principles of static and dynamic similitude were applied to typical complex structural components for the purpose of examining the application of modeling techniques to sonic fatigue predictions. Modeled specimens of curved panels, honeycomb sandwich flat panels, and honeycomb sandwich cantilever beams have been tested. The tests were conducted on full scale 5/8, and 3/8 size models. The tests and analyses demonstrated that scale reductions of linear panel dimensions, and other size factors necessary in the fabrication of models, may be separately considered in maintaining the established similitude relationships. Both random spectra and discrete frequency acoustic excitation are considered. Stress correlation is the critical parameter in modeling for acoustic fatigue. True models with exact geometric scaling in all elements are not necessary. Adequate modeling is obtained by maintaining the same aspect ratio and modes for the specimen and model. The frequency and stress then vary at predetermined magnitudes with a functional relationship to damping, amplitude, and cross-section (thickness) geometric parameters. Non-linear effects are dependent on excitation levels. In general, a prerequisite to sonic fatigue tests is a knowledge of the non-linearity induced by damping and amplitude for each specimen. The experimental data confirms the application of basic procedures formulated by Miles, Palmgren, and Miner which minimize the requirement for random excitation in the use of modeling techniques for sonic fatigue predictions.

Report Availability

Full text available

Date Issued

1966-06

Provenance

Lockheed Martin Missiles & Fire Control

Type

report

Subject

Structural Components

Experimental Data

Predictions

Panels

Cantilever Beams

Curved Profiles

Honeycomb Cores

Test Methods

Model Tests

Sonic Fatigue

Format

1 online resource

Creator

Wang, P.