Title

EVALUATION OF THE DRIVING FORCE IN FATIGUE CRACK GROWTH, IN PLANE STRAIN AND PLANE STRESS STATE TESTS, UNDER CONSTANT ΔK

Authorship

González, Julián Andrés Ortiz; Castro, Jaime Tupiassú Pinho de

González, Julián Andrés Ortiz

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Castro, Jaime Tupiassú Pinho de

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DOI

10.5151/1516-392X-26443

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Abstract

This work presents a series of experiments of Fatigue Crack Growth (FCG), which are intended to provide evidence about the main parameter controlling this phenomenon, whereas still no agreement about this, since the Paris´ theory is based on the principle that FCG is controlled by the ΔK and the Elber´s theory says that the driving force is ΔKeff. For the development of the experiments, some DC(T) specimens were machined with two different thicknesses: 2 and 30 mm to perform FCG tests in plane stress and plane strain state, respectively. Besides this, all FCG tests were carried out with a constant ΔK e Kmax, measuring the strain with a Strain-Gage bonded on the back face of the specimen and seven Strain-Gages located on the crack growth path. The data needed to measure the crack opening load, and the ΔKeff, were collected through a program developed in Labview. Finally, the data post-processing was carried out based on the ASTM standards and several articles of recognized authors in this field, in order to compare the two positions with the experimental data, and this way conclude which is the most consistent theory with the observed behavior.

Keywords

Fatigue crack growth, Crack closure, Crack opening load

Crack opening load