FATIGUE CRACK PROPAGATION under VARIABLE-AMPLITUDE LOAD: Part i - A Deterministic State-Space Model

Ravindra Patankar, Asok Ray

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The two-part paper addresses modeling of fatigue crack damage in metallic structures for on-line diagnostics and health monitoring of operating machinery. This paper which is the first part presents a dynamical model of fatigue crack propagation in the deterministic state-space setting based on the crack closure concept under cyclic stress excitation of variable-amplitude loading where the model state variables are crack length and crack opening stress. The second part which is a companion paper extends the deterministic model to formulate a stochastic state-space model of fatigue crack propagation under both constant-amplitude and variableamplitude load. The state-space model is capable of capturing the effects of stress overload and underload on crack retardation and sequence effects, and the model predictions are in fair agreement with experimental data on the 7075-T6 aluminum alloy. Furthermore, the state-space model recursively computes the crack opening stress via a simple functional relationship and does not require a stacked array of peaks and valleys of stress history for its execution. Therefore, savings in both computation time and memory requirement are significant. As such, the state space model of fatigue crack propagation allows real-time execution of decision algorithms for diagnostics, risk analysis, and life prediction on inexpensive platforms such as a Pentium processor.

Original languageEnglish (US)
Title of host publicationDynamic Systems and Control
PublisherAmerican Society of Mechanical Engineers (ASME)
Pages15-22
Number of pages8
ISBN (Electronic)9780791815861
DOIs
StatePublished - 1998
EventASME 1998 International Mechanical Engineering Congress and Exposition, IMECE 1998 - Anaheim, United States
Duration: Nov 15 1998Nov 20 1998

Publication series

NameASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE)
Volume1998-I

Conference

ConferenceASME 1998 International Mechanical Engineering Congress and Exposition, IMECE 1998
Country/TerritoryUnited States
CityAnaheim
Period11/15/9811/20/98

All Science Journal Classification (ASJC) codes

  • Mechanical Engineering

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