Everyone loves an elegant engineering solution. It is particularly true when the alternatives are terrifying. In the paper:
”Brittle crack propagation/arrest behaviour in steel plate – Part I: Model formulation” by Kazuki Shibanuma, Fuminori Yanagimoto, Tetsuya Namegawa, Katsuyuki Suzuki, Shuji Aihara in Engineering Fracture Mechanics, 162 (2016) 324-340.
A nice demonstration of toughening by introducing multiple secondary cracking of planes parallel with the primary crack is found in the paper:
In this review of particularly readworthy papers in EFM, I have selected a paper about the tearing of large ductile plates, namely:
Cracks typically follow paths that locally give a mode I crack tip load. At mixed modes crack are extended via a kink in a direction that locally restores mode I. In isotropic materials this is known to more or less, true for static and dynamic loads. Exceptions are cracks that are subjected to high compressive load, e.g., at contact between train wheels and rails or at cracks caused by seismic movements. Other exceptions are cracks growing in anisotropic materials, at grain boundaries or other weak, or by deformation weakened, interfaces.
The recently published
In the latest volume of Engineering Fracture Mechanics there is an interesting paper about the calculation of crack growth paths by use of a phase field model. The considered material is inhomogeneous and that causes the crack to follow a winding path through the material. The material structure is from a CT scanned micro-structure of a cement-based porous material. The paper is:
According to the Swedish Plant Inspectorate the major part of all reported fracture related failures in Sweden are due to stress corrosion. I guess it is more or less a reality everywhere. The association with accidents is probably because it comes without warning and usually at surprisingly low loads. Just a mm sized spot of decomposing grease is enough to create a locally extremely acid environment. In an otherwise friendly environment this often not even considered as a possibility by the designer.
The paper for this discussion is:
Dear Reader,
I recently took over as the ESIS blog editor. Being the second in this baton relay, I will do my best to live up to the good reader expectations that have been established by my precursor, who is also one of the instigators of the blog, Wolfgang Brocks.
P.M. James: Re-derivation of plasticity interaction for combined loading under significant levels of elastic follow-up. Engineering Fracture Mechanics, Vol. 126, 2014, pp. 12–26.
K. Özenç, M. Kaliske, G. Lin, G. Bhashyam: Evaluation of energy contributions in elasto-plastic fracture: A review of the configurational force approach, Engineering Fracture Mechanics, 2014, Vol. 115, pp. 137-153.
T. Yasuoka, Y. Mizutani, A. Todoroki: Applicable limit of the stress intensity factor for steep yield strength distribution, Engineering Fracture Mechanics, 2013, Vol. 110, pp. 1-11.
