Aluminum 7075-T6 fatigue data generation and probabilistic life prediction formulation
Loading...
Authors
Kemna, John G.
Subjects
Aluminum 7075-T6
Fatigue-life prediction
Fatigue data base
Probability
Reliability
Damage accumulation
Maximum likelihood analysis
Fatigue-life prediction
Fatigue data base
Probability
Reliability
Damage accumulation
Maximum likelihood analysis
Advisors
Wu, Edward M.
Date of Issue
1998-09-01
Date
September 1998
Publisher
Monterey, California. Naval Postgraduate School
Language
en_US
Abstract
The life extension of aging fleet aircraft requires an assessment of the safe-life remaining after refurbishment. Risk can be estimated by conventional deterministic fatigue analysis coupled with a subjective factor of safety. Alternatively, risk can be quantitatively and objectively predicted by probabilistic analysis. In this investigation, a general probabilistic life formulation is specialized for constant amplitude, fully reversed fatigue loading utilizing conventional breakdown laws applied to the general probability damage function. Experimental data was collected both as a bench mark data base, as well as an example of the implementation of probabilistic fatigue life prediction. Fully reversed, sinusoidal fatigue testing under load control was carried Out at load levels giving high cycle fatigue lives from 1 x 104 to 5 x 106 cycles. The number of replications at each stress level is greater than currently available in the literature, thereby increasing the confidence of predictions in the long-life domain, as well as extending the statistical basis for probabilistic inference. The load level data sets are interpreted by the probabilistic damage function for life location as well as life shape parameters using maximum likelihood analysis. Homologous life ranking and the minimum entropy hypothesis are investigated as well.
Type
Thesis
Description
Series/Report No
Department
Department of Aeronautics and Astronautics
Organization
Naval Postgraduate School
Identifiers
NPS Report Number
Sponsors
Funding
Format
x, 107 p.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.