Development of a computer program for the analysis of fatigue crack growth

Dalgıç, Ali Murtaza
In this study, a computer program is developed for fatigue crack propagation analysis of metal alloys and random fiber composites. The developed program takes the fatigue crack propagation experiment data in the form of crack length vs. number of cycles from the user. The user also, selects the crack geometry and defines loading conditions of the test specimen. Developed program analyze the experimental data and evaluates crack growth rate and stress intensity range. For the calculated or ready crack growth rate data, computer program evaluates the fatigue crack growth rate dependence of stress intensity range. For this purpose computer program uses Paris Model for metal alloys and Modified Paris Model for random fiber composites. In logarithmic scale best line curve fit is done to the crack growth rate data and power law constants are calculated for the Paris and Modified Paris Models. Evaluated power law constants are used for the life estimation with Paris and Modified Paris Models. All entered and evaluated data are shown in graphical and tabular form. These values are stored for further applications.


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In this study, the fatigue behaviour of aluminium matrix-silicon carbide (SiC) particulate reinforced composite specimens was investigated in comparison to the matrix aluminium alloy containing 12 wt% Si. Three different weight percentages of SiC particulates: 5, 10, and 15 in the size range of 40-60 gm were injected into the melt. Mg was also added to improve the wettability of Al-alloy matrix over SiC particulates resulting in better interfacial bonding. Test specimens were machined from squeeze casting b...
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In the scope of this study, a new test procedure is developed to investigate the thermal fatigue performance of asphalt concrete materials. To achieve this, test samples are compacted using different mixtures to be designed according to the Superpave mix design method. In the testing program, compacted samples are cut to produce beam specimens for thermal coefficient tests and semicircular specimens for thermal fatigue tests. Analysis of variance (ANOVA) and Multivariate analyses are both used to evaluate t...
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A systematic study of the titanium doped aluminum clusters with various spin multiplicities have been performed by using Density Functional Theory calculations at the B3LYP/6-311++G(d,p) level. The HOMO-LUMO energy gap, ionization potential (IP), electron affinity (EA), Adiabatic Electron Affinity (AEA), Vertical Electron Affinity (VDE) and vertical detachment energy (VDE) are also computed for the most stable isomer of each cluster.
Development of a regression model for the fatigue life assessment of open-hole specimens with double through the thickness cracks
Heidari Shabestari, Seyed Sohrab; Kayran, Altan; Department of Aerospace Engineering (2019)
This thesis mainly deals with the investigation of the fatigue crack growth characteristics of open rivet holes in aluminum 2024-T3 material. In this respect, most commonly observed type of cracks emanating from rivet holes, namely, double through the thickness edge cracks with centered configurations has been considered. Stress intensity factors and the fatigue lifes are calculated analytically and also with the Extended Finite Element Method (XFEM).Analytical calculations have been carried out using the c...
Citation Formats
A. M. Dalgıç, “Development of a computer program for the analysis of fatigue crack growth,” Middle East Technical University, 2002.