Estimation of the stress intensity factors of cracks and notches in anisotropic multi-material and inclusion material

  • 邱 乾艷

Student thesis: Doctoral Thesis

Abstract

Cracks and notches often occur in engineered objects and failures can then initiate from these critical regions due to the resulting discontinuities in geometry and material properties This can occur with large items such a the beam-column joints of steel structures welding members and in aerospace vessel and automobile components as well as smaller items such as those found in electronic packaging semiconductor packaging and solar panels While there are many studies that examine problems related to homogenous cracks and notches relatively few consider the stress intensity factors (SIFs) of cracks and notches in anisotropic multi-material and inclusion problems This study thus estimated the notch-tip and crack-tip coordinates as well as the SIFs using image-correlation experiments with the least-squares method In this approach the complex displacement functions are deduced into a least-squares form and then displacement fields from the image-correlation experiments are substituted into the least-squares equation to obtain the SIFs The results of the experiments are compared using H-integral and finite element analyses and this reveals that the SIFs obtained using the proposed method are acceptably accurate The major advantage of this approach is that it is easy simple and systematic and the experimental data required for it do not need to include that near the notch tip or specimen boundaries In addition it is not necessary to smooth the experimental data since the least-squares method can average the deviations in this The proposed method thus provides a very simple and convenient tool for researchers to obtain the SIFs of notch and crack problems
Date of Award2014 Aug 15
Original languageEnglish
SupervisorShen-Haw Ju (Supervisor)

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