The modulus and internal friction of Armco iron rere continuously measured during cathodic charging rith hydtogen to investigate crack initiation and grorth. The observed modulus decrease ras attributed to crack initiation and grorth. The internal friction increase doring cathodic charging ras atfributed to plastic deformation accompanying the crack formation. Both the modulos and internal fric...

The filling of strand corrosion products during concrete crack propagation is investigated experimentally in the present paper. The effects of stirrups on the filling of corrosion products and concrete cracking are clarified. A prediction model of crack width is developed incorporating the filling proportion of corrosion products and the twisting shape of the strand. Experimental data on cracki...

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...

The effect of V-notches or reentrant corners on fracture propagation has been analyzed for brittle materials, but not for quasibrittle materials such as concrete, marked by a large material characteristic length producing a strong size effect transitional between plasticity and linear elastic fracture mechanics. A simple size effect law for the nominal strength of quasibrittle structures with s...

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 ...