With the characteristics of ANN’s strong capability on nonlinear approximation, a new method by combining an artificial neural network with back-propagation learning algorithm and modal analysis via finite element model of cracked rotor system is proposed for fast identification of crack fault with high accuracy in rotating machinery. First, based on fracture mechanics and the energy principle ...

This paper presents the simple method to determine the complex stress intensity factor of interface crack problem by the finite element method. The proportional method is extended to the interface crack problem. In the present method, the stress values at the crack tip calculated by FEM are used and the stress intensity factors of interface crack are evaluated from the ratio of stress values be...

The chipping process in a brittle material subjected to a uniformly applied edge load has been investigated. The present analysis extends earlier work by recognizing that as the chip is formed it may bend and change the loading at the crack tip. This geometry change introduces a nonlinear effect and has significant influence on the phenomenon. The nonlinear effect was demonstrated by incorporat...

The nite element method is now well established as a robust and reliable numerical technique in many areas of solid mechanics. There are however problems where the use of the nite element method is cumbersome like the modeling of moving discon-tinuities due to the need to update the mesh to match the geometry of the discontinuity. Even for stationary cracks, in three-dimensional solids, contsru...

Crack detection is one of the important tasks for industrial materials and products from the standpoint of safety. The assessment of the crack geometry would be a crucial parameter for quality control of products. The crack width and length could be rather easily identified by inspecting the actual surface picture. However, the depth of small crack would be difficult to estimate non-destructive...

Recent work (Rice, 1985a) has presented the calculations of the first order variation in an elastic displacement field associated with arbitrary incremental planar advance of the location of the front of a half-plane crack in a loaded elastic full space. That work also indicated the relation of such calculations to a three-dimensional weight function theory for crack analysis and derived an exp...

The presented work introduces a numerical parametric study on the crack propagation direction under mixed-mode conditions (mode I + II). It is conducted for the geometry of an eccentric asymmetric fourpoint bending of a single edge notched beam specimen; various levels of mode-mixity are ensured by modifications in the crack length and crack eccentricity. The direction of crack propagation is e...

OBJECTIVE To understand crack cocaine craving among users and describe craving behaviors and coping strategies. METHODOLOGICAL PROCEDURES Qualitative study with a non-random criterion sample consisting of 40 current and former crack cocaine users conducted in São Paulo, southeast Brazil, in 2007 and 2008. Respondents were selected using snowball sampling technique. In-depth semi-structured in...

An evolutionary approach for fatigue crack detection in cantilever type of machine structure is investigated in this paper. Fault like fatigue crack detection has received a great attention in recent years. A surface transverse open edge crack is considered for this study. Actual fatigue crack may behave like a non-linear due to opening and closing under vibration. But due to small level of vib...

The creep crack problems in damaged materials under mixed mode loading (Mode I and Mode II loading) in the framework of creep-damage coupled formulation are considered. The class of the self-similar solutions to the plane creep crack problems in a damaged medium under mixed-mode loading is given. With the similarity variable and the self-similar representation of the solution for a power-law cr...