The relationships between the fatigue crack growth rate ( d a / d N ) and stress intensity factor range ( Δ K ) are not always linear even in the Paris region. The stress ratio effects on fatigue crack growth rate are diverse in different materials. However, most existing fatigue crack growth models cannot handle these nonlinearities appropriately. The machine learning method provides a flexibl...

Ultrasonic in situ monitoring of metal alloys has been successfully demonstrated for determining the presence and size of fatigue damage within a stracture. Ultrasonic techniques, however, only provide an estimate of the state of the stracture at that time and do not predict the remaining fatigue life. On the other hand, a statistical crack propagation approach, which models the expected remain...

An efficient and highly accurate, Symmetric Galerkin Boundary Element Method Finite Element Method based alternating method, for the analysis of three-dimensional non-planar cracks, and their growth, in structural components of complicated geometries, is proposed. The crack is modeled by the symmetric Galerkin boundary element method, as a distribution of displacement discontinuities, as if in ...

Numerical simulation of cracked structures is an important aspect in structural safety assessment. In recent years, there has been an increasing rate of development of numerical codes for modeling fracture procedure. The subject of this investigation is implementing automated fracture models in the DYNA3D nonlinear explicit finite element code to simulate pseudo 3-D crack growth procedure. The ...

Step-loading fatigue tests have been conducted on two � -TiAl alloys with differing microstructures following quasi-static indentations intended to simulate assembly-related impact damage to lowpressure turbine blades. Fatigue tests were conducted at 600 �C using computer-controlled servohydrau­ lic loading at a frequency of 20 Hz. Reasonably good agreement was achieved between the fatigue data...

Self-healing concrete (SHC) has received a tremendous attention due to its advanced ability of automatic crack detection and crack repairing compared to the standard concrete. Two main approaches which considered as to-date self-healing mechanisms are autogenous and autonomous healing. In the past several years, the effort of the research has been focused on experimental works instead of numeri...

In this paper, the mechanical behavior of three-phase inhomogeneous materials is modeled using the meso-scale model with lattice beams for static and dynamic analyses. The Timoshenko beam theory is applied instead of the classical Euler-Bernoulli beam theory and the mechanical properties of lattice beam connection are derived based on the continuum medium using the non-local continuum theory. T...

the cracked brazilian disc (cbd) specimen is widely used in order to determine mode-i/ii and mixed-mode fracture toughness of a rock medium. in this study, the stress intensity factor (sif) on the crack-tip in this specimen is calculated for various geometrical crack conditions using the extended-finite element method (x-fem). this method is based upon the finite element method (fem). in this m...

This paper presents a modeling approach for studying hydro-mechanical coupled processes, including fracture development, within geological formations. This is accomplished through the novel linking of two codes: TOUGH2, which is a widely used simulator of subsurface multiphase flow based on the finite volume method; and an implementation of the Rigid-BodySpring Network (RBSN) method, which prov...