Persistent Link:
http://hdl.handle.net/10150/184822
Title:
Damage accumulation in random loads.
Author:
Perng, Horng-Linn.
Issue Date:
1989
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
An equivalent constant amplitude fatigue loading (Miner's stress) is developed for stationary random amplitude loadings. The effects of rainflow cycle counting and fatigue crack closure are included. A method for determining the opening stress in a random loading is also proposed. This research takes a fatigue damage factor approach. The damage factor is defined as the ratio of the wide band rainflow fatigue damage to the equivalent narrow band fatigue damage. The mathematical form of the damage factor equations is derived from theoretical derivations using the analytically tractable local range cycle counting method. Simulations of stationary Gaussian random processes are used to empirically derive the values of certain parameters dependent on the spectral shape for the rainflow cycle counting equations. There are five tasks in this research. (1) A simulation program for generating a Gaussian process has been written and is used to generate random loading histories for this study. (2) A previously proposed rainflow damage factor has been verified and refined with these simulations, without considering crack closure. (3) Using a sinusoidal approximation, the joint probability density functions between peaks, valleys and rises counted by the local range method are derived. (4) The resulting joint probability distributions are used to determine the theoretical damage with crack closure; simulations are again used to calibrate the parameters for rainflow stress cycles. (5) A procedure for finding an equivalent constant fatigue crack opening stress for stationary random loadings is described. An example application of the procedures and equations is given.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Materials -- Fatigue.; Fracture mechanics.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Aerospace and Mechanical Engineering; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Ortiz, Keith

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleDamage accumulation in random loads.en_US
dc.creatorPerng, Horng-Linn.en_US
dc.contributor.authorPerng, Horng-Linn.en_US
dc.date.issued1989en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractAn equivalent constant amplitude fatigue loading (Miner's stress) is developed for stationary random amplitude loadings. The effects of rainflow cycle counting and fatigue crack closure are included. A method for determining the opening stress in a random loading is also proposed. This research takes a fatigue damage factor approach. The damage factor is defined as the ratio of the wide band rainflow fatigue damage to the equivalent narrow band fatigue damage. The mathematical form of the damage factor equations is derived from theoretical derivations using the analytically tractable local range cycle counting method. Simulations of stationary Gaussian random processes are used to empirically derive the values of certain parameters dependent on the spectral shape for the rainflow cycle counting equations. There are five tasks in this research. (1) A simulation program for generating a Gaussian process has been written and is used to generate random loading histories for this study. (2) A previously proposed rainflow damage factor has been verified and refined with these simulations, without considering crack closure. (3) Using a sinusoidal approximation, the joint probability density functions between peaks, valleys and rises counted by the local range method are derived. (4) The resulting joint probability distributions are used to determine the theoretical damage with crack closure; simulations are again used to calibrate the parameters for rainflow stress cycles. (5) A procedure for finding an equivalent constant fatigue crack opening stress for stationary random loadings is described. An example application of the procedures and equations is given.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectMaterials -- Fatigue.en_US
dc.subjectFracture mechanics.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineAerospace and Mechanical Engineeringen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorOrtiz, Keithen_US
dc.contributor.committeememberWirsching, Paul H.en_US
dc.contributor.committeememberKececioglu, Dimitrien_US
dc.identifier.proquest9004973en_US
dc.identifier.oclc703274099en_US
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