The numerical simulation of fatigue behavior of the Aluminum 7075-T6 cantilever beam with an angular crack has been investigated. Cracks are located separately in three different positions of the investigated beam. To predict the fatigue behavior of the cantilever beam the crack propagation was manually simulated. Compression load is applied in different stress ratios between zero and one; then, the obtained numerical results of this research are compared with the experimental results. It is observed that increasing the stress ratio increases the percentage of the fatigue life of the sample significantly. Ascending growth of fatigue life is slow and more severe by increasing of the stress ratio for the first and the third position, respectively. By increasing the stress ratio, the rate of deviation of the crack decreases and it converges to 0° in parallel to the width of the beam. This result is also observed with an increase in the distance from the support of beam. Furthermore, it is also revealed that by the increase in the initial length of the crack, the fatigue life initially reduces with smaller ratios. However, along the larger cracks, the decreasing ratio of fatigue life increases significantly.

This piece of work aims at the modeling and using the finite element method approach (FEM) to analyze the fatigue behavior of bolted beam to column end-plate connection in the structural steel framework subjected to static loading. A detailed three dimensional (3D) simulation model of the bolted beam to column end-plate connection is constructed in PRO-E wildfire and it is analyzed in the ANSYS workbench to obtain its behavior. The bolted end-plate connection is chosen as an important type of beam to column joint. The end-plate connection is chosen for its complexity in the analysis and behavior due to the number of connection components and their inheritable behavior. The solid elements, bonded contact and the bolt pretension are included to obtain the behavior of the structure. The FEA results of the structure with or without bolt pretension are compared with the available literature. At last the fatigue behavior of connections under over tensioning is presented in this work.