Abstract
The aim of this paper is to calculate how the surface crack front and the dimensionless compliance evolve in cracked cylindrical bars subjected to cyclic tension or bending with different initial crack geometries (crack depths and aspect ratios). To this end, a computer application (in the Java programming language) that calculates the crack front’s geometric evolution and the dimensionless compliance was made by discretizing the crack front (characterized with elliptical shape) and assuming that every point advances perpendicularly to the crack front according to the Paris law, and using a three-parameter stress intensity factor (SIF). The results show that in fatigue crack propagation, relative crack depth influences more on dimensionless compliance than the aspect ratio, because the crack front tends to converge when the crack propagates from different initial geometries, showing greater values for tension than for bending. Furthermore, during fatigue crack growth, materials with higher values of the exponent of the Paris law produce slightly greater dimensionless compliance and a better convergence between the results for straight-fronted and circular initial cracks.
Highlights
The problem of fatigue crack propagation in round bars is of great interest in fracture mechanics, applied to linear structural elements
The results show that in fatigue crack propagation, relative crack depth influences more on dimensionless compliance than the aspect ratio, because the crack front tends to converge when the crack propagates from different initial geometries, showing greater values for tension than for bending
If the crack is characterized by an elliptical shape, there are two factors exerting influence: the relative crack depth, which causes an increase of its value, and the aspect ratio, which causes a decrease of its value [3, 11]
Summary
The problem of fatigue crack propagation in round bars is of great interest in fracture mechanics, applied to linear structural elements. The most used are those based on the Paris-Erdogan law [2,3,4,5,6], requiring the knowledge of the dimensionless stress intensity factor (SIF), Y, along the crack front in the round cracked bar. It has been deducted by several authors following different procedures: compliance methods, finite element analysis, boundary integral equation methods, experimental techniques, etc. There is a relation between the change in compliance during fatigue crack growth and the crack geometry evolution, depending on the specimen material, the initial crack geometry and the type of applied load [10, 12]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
