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Practical implementation of the double linear damage rule and damage curve approach for treating cumulative fatigue damageSimple procedures are given for treating cumulative fatigue damage under complex loading history using either the damage curve concept or the double linear damage rule. A single equation is given for use with the damage curve approach; each loading event providing a fraction of damage until failure is presumed to occur when the damage sum becomes unity. For the double linear damage rule, analytical expressions are given for determining the two phases of life. The procedure comprises two steps, each similar to the conventional application of the commonly used linear damage rule. Once the sum of cycle ratios based on Phase I lives reaches unity, Phase I is presumed complete, and further loadings are summed as cycle ratios based on Phase II lives. When the Phase II sum attains unity, failure is presumed to occur. It is noted that no physical properties or material constants other than those normally used in a conventional linear damage rule analysis are required for application of either of the two cumulative damage methods described. Illustrations and comparisons are discussed for both methods.
Document ID
19810049119
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Manson, S. S.
(Case Western Reserve University Cleveland, Ohio, United States)
Halford, G. R.
(NASA Lewis Research Center Cleveland, Ohio, United States)
Date Acquired
August 11, 2013
Publication Date
April 1, 1981
Publication Information
Publication: International Journal of Fracture
Volume: 17
Subject Category
Structural Mechanics
Accession Number
81A33523
Distribution Limits
Public
Copyright
Other

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