This paper explores the fracture process based on finite element simulation. Both probabilistic and deterministic methods are employed to model crack initiation, and several commonly used criteria are utilized to predict crack growth. It is concluded that the criteria of maximum tensile stress, maximum normal stress, and maximum Mises stress, as well as the Coulomb-Mohr criterion are able to pr...

This paper presents a low cycle fatigue life curve by simulating a crack in a cover plate welded moment connection. Initiation of ductile fracture in steel is controlled by growth and coalescence of micro-voids. This research used a numerical method using finite element modeling and simulation of ductile crack initiation by a micromechanical model. Therefore, a finite element model of a cover p...

The very high cycle fatigue behavior (10-10 cycles) of Ti-6246 has been investigated using ultrasonic fatigue techniques. In this regime of fatigue (0.4-0.6σYS), only certain microstructural regions are susceptible to fatigue damage accumulation, and lifetimes are related to the distribution of fatigue critical microstructural neighborhoods. Three distinct categories of crystallographic crack i...

In order to investigate the methods to heal fatigue cracks in metals, tubular specimens of 1045 steel with axial and radial fatigue cracks were treated under the eddy current. The optical microscope was employed to examine the change of fatigue cracks of specimens before and after the eddy current treatment. The results show that the fatigue cracks along the axial direction of the specimen coul...

In this paper we study the crack initiation in a hyper-elastic body governed by a Gri th's type energy. We prove that, during a load process through a time dependent boundary datum of the type t→ tg(x) and in absence of strong singularities (this is the case of homogeneous isotropic materials) the crack initiation is brutal, i.e., a big crack appears after a positive time ti > 0. On the contrar...

In this paper we study the crack initiation in a hyper-elastic body governed by a Griffith’s type energy. We prove that, during a load process through a time dependent boundary datum of the type t → tg(x) and in absence of strong singularities (this is the case of homogeneous isotropic materials) the crack initiation is brutal, i.e., a big crack appears after a positive time ti > 0. On the cont...

Crack tip deformations and fracture parameters in functionally graded glass-filled epoxy beams are experimentally evaluated under static and dynamic loading conditions. Beams with unidirectional, monotonic elastic gradients and cracks along the gradient are examined. SEN samples with increasing or decreasing Young’s modulus ahead of the crack tip are studied in symmetric four-point bending and ...

Shot peening beneficial effects on fatigue life of mechanical components are well known. However, there are some reports in the literature that indicate inappropriate shot peening parameters tend to reduce the fatigue life. It is therefore, the purpose of this study to find a logical quantitative justification for these observations. Using finite element method, a dynamic elastic-plastic simula...

An elastic finite element analysis was conducted to evaluate the stress distribution in the initiation zone of the adhesive rupture during the 3-point bending test. This test is used to measure the adherence between a polyepoxy adhesive and aluminum alloy with different surface treatments. The purpose is to compare, in the high stress concentration areas, the stress fields calculated using fini...

Analysis has been performed on fracture initiation near a crack in a brittle material with strength described by Weibull statistics. This nonlocal fracture model allows for a direct correlation between near crack-tip stresses and failure. Predictions are made for both the toughness and average fracture initiation angle of a crack under mixed-mode loading. This is pertinent for composites and is...