National Technical Reports Library

The National Technical Information Service acquires, indexes, abstracts, and archives the largest collection of U.S. government-sponsored technical reports in existence. The NTRL offers online, free and open access to these authenticated government technical reports. Technical reports and documents in its repository may be available online for free either from the issuing federal agency, the U.S. Government Publishing Office’s Federal Digital System website, or through search engines.

Details

Modeling Techniques for Sonic Fatigue Prediction.

AD648078

Publication Date	1966
Personal Author	Wang, P.
Page Count	143
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. (Author)
Keywords	Sonic fatigue Structural parts Model tests Test methods Panels(Structural) Curved profiles Honeycomb cores Sandwich panels Cantilever beams Predictions Stresses Experimental data
NTIS Subject Category	46E - Structural Mechanics
Corporate Authors	North American Aviation Inc Los Angeles Calif Los Angeles Div
Document Type	Technical Report
Title Note	Final rept. May 64-Oct 65.
NTIS Issue Number	196709
Contract Number	AF 33(615)-1743

Modeling Techniques for Sonic Fatigue Prediction.

Modeling Techniques for Sonic Fatigue Prediction.
AD648078

Publication Date	1966
Personal Author	Wang, P.
Page Count	143
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. (Author)
Keywords	Sonic fatigue Structural parts Model tests Test methods Panels(Structural) Curved profiles Honeycomb cores Sandwich panels Cantilever beams Predictions Stresses Experimental data
NTIS Subject Category	46E - Structural Mechanics
Corporate Authors	North American Aviation Inc Los Angeles Calif Los Angeles Div
Document Type	Technical Report
Title Note	Final rept. May 64-Oct 65.
NTIS Issue Number	196709
Contract Number	AF 33(615)-1743