Damage precursor detection using nonlinear dynamic parameters and micromechanics

Ed Habtour, Daniel P. Cole, Abhijit Dasgupta, Mark Robeson

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

Abstract

A nonlinear vibration methodology coupled with micromechanics is developed for detecting and estimating fatigue damage precursor s in metallic alloy structures , where damage precursor is defined as detectable change in the materials proper ties prior to crack initiation. The proposed methodology is based on measuring the structural nonlinear response due to nonlinear base excitation . The damage precursor feature can be extracted by quantifying the reduction in the nonlinear stiffness parameter due to localized increase in the material compliance due to micro structural changes at high stress concentration sites. A case study is presented where a simple structure is subjected to various base excitations. A t high response amplitudes, the structure is observed to experience three competing nonlinear response mechanisms: 1) kinematic stiffening due to high response amplitude at the fundamental mode, 2) softening due to inertial forces, and 3) softening due to localized change in the micromechanical properties of the material . Micromechanics characterization techniques are utilized to confirm the presence of fatigue damage precursors. Micromechanics technique s are employed to assess the changes in material ' s properties due to damage build up. This paper demonstrates that the sensitivity of the SHM metrics can be significantly improved if one looks at nonlinear dynamic response.

Original languageEnglish
Title of host publicationStructural Health Monitoring 2015
Subtitle of host publicationSystem Reliability for Verification and Implementation - Proceedings of the 10th International Workshop on Structural Health Monitoring, IWSHM 2015
EditorsFu-Kuo Chang, Fotis Kopsaftopoulos
PublisherDEStech Publications, Inc
Pages1267-1274
Number of pages8
Volume2
ISBN (Electronic)9781605951119
DOIs
Publication statusPublished - 1 Jan 2015
Externally publishedYes
Event10th International Workshop on Structural Health Monitoring, IWSHM 2015: System Reliability for Verification and Implementation - Stanford University , Stanford, United States
Duration: 1 Sep 20153 Sep 2015
Conference number: 10
http://web.stanford.edu/group/sacl/workshop/IWSHM2015/home.html

Conference

Conference10th International Workshop on Structural Health Monitoring, IWSHM 2015
Abbreviated titleIWSHM
CountryUnited States
CityStanford
Period1/09/153/09/15
Internet address

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