A Multi-dimensional Experimental Method for Investigating Fatigue Crack Growth with Overloads

JING-YU ZHANG, WEI-FANG ZHANG, HONG-XUN WANG, WEI DAI

Abstract


The comprehensive multi-dimensional experimental method is proposed to concurrently investigate the crack growth rate, microstructure effect, crack closure and crack tip plastic zone in one fatigue crack growth experiment. In the proposed methodologies, the fatigue crack growth experiment is performed to loading the specimen under constant amplitude loading, and the crack opening displacement (COD) gauge is used to measure the crack length. A self-developed micro-optical system is used to verify crack length at the same time and study the effect of microstructure on crack growth. Then the correlation between crack growth rate and stress intensity factor (SIF) range is studied to investigate the crack growth mechanism. The images near crack tip are taken to investigate the crack closure and crack tip plastic zone by using digital image correlation (DIC) measurement.

Keywords


Fatigue crack growth, Overload, Crack tip plastic zone, Digital image correlation.Text


DOI
10.12783/dteees/epme2018/24641

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