Accession Number : AD0715273

Title :   Choice of Materials on the Basis of Random Vibration and Structural Fatigue,

Corporate Author : NEW MEXICO UNIV ALBUQUERQUE DEPT OF MECHANICAL ENGINEERING

Personal Author(s) : Yeh,H. Y. ; Ju,F. D. ; Yao,J. T. P.

Report Date : MAY 1970

Pagination or Media Count : 17

Abstract : A method is presented for the evaluation of alternative materials to be used in structures subjected to random low cycle excitation. The fracture criterion is based upon the revised Palmgren-Miner cumulative damage hypothesis in terms of plastic deformation. It is then used with a given statistics of random low cycle loading in the formulation to compute the expected value and variance of the life. As a numerical example, two aluminum alloys, one with high strength but low ductibility (2024-T4; yield strength 52 ksi and 'true strain' at fracture 0.35) and another with low strength but high ductibility (6061-T6 yield strength 25 ksi and 'true strain' at fracture 0.45) are considered as alternative materials for use in an idealized beam subjected to random excitation. In this particular case, 2020-T4 even with its higher strength gives smaller expected value of structurel life to fracture. (Author)

Descriptors :   (*ALUMINUM ALLOYS, *FATIGUE(MECHANICS)), (*BEAMS(STRUCTURAL), LOADS(FORCES)), FAILURE(MECHANICS), VIBRATION, WHITE NOISE, LIFE EXPECTANCY, MATHEMATICAL MODELS

Subject Categories : Metallurgy and Metallography
      Mechanics
      Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE