In this paper, we propose a method for calculating stress intensity factors of plane fracture problems with cracks by coupling the ®nite element method (FEM) and the direct method of lines. We introduce polygonal arti®cial boundaries and divide the physical domain into two parts: a large domain without any crack tips and small polygonal domains surrounding the crack tips. We solve the problem d...

In service, cracks or microcracks are usually present in concrete as a result of several mechanisms, for example the drying shrinkage, thermal gradients, freezing-thawing cycles, alkali-aggregate reaction and external loading. It has been realized that cracking can significantly accelerate the ingress of chlorides into concrete since it provides preferential flow channels and allow more chlorid...

Model-based gear dynamic analysis and simulation has been a promising way for developing effective gearbox vibration monitoring approaches. In this paper, based on the dynamic model of a one-stage gearbox with spur gears and one tooth crack, statistical indicators and the discrete wavelet transform (DWT) technique are investigated to identify effective and sensitive health indicators for reflec...

Centrifugal booster fans are important equipment used to recover blast furnace gas (BFG) for generating electricity, but blade crack faults (BCFs) in centrifugal booster fans can lead to unscheduled breakdowns and potentially serious accidents, so in this work quantitative fault identification and an abnormal alarm strategy based on acquired historical sensor-dependent vibration data is propose...

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...