Laser processing of cutting tool materials particularly cemented carbides can induce many surface defects including porosity, balling, and micro-cracks. When present in the microstructure tools, micro-cracks lead to chipping early failure. The detection identification cracks be used predict performance post laser processing. To develop a method for crack scanning electron microscopy (SEM) image...

The paper deals with the identifiability of non-smooth defects by boundary measurements, and the stability of their detection. We introduce and analyse a new pointwise regularity concept at the boundary of an open set which turns out to play a crucial role in the identifiabilty of defects by two boundary measurements. As a consequence, we prove the unique identifiability for a large class of cl...

A novel methodology to identify a fatigue crack propagation law is proposed. It is based on an optimization scheme that directly interrogates the images from the sought law rather than using a sequence of fitting schemes. Two procedures are presented and tested first on artificial data with a known law, and second on an actual image series obtained from a fatigue test performed on a thin titani...

We discuss apparent characteristic features of Rayleigh scattering of elastic waves from cracks. Interpreting these features, we propose a procedure that in some experimental situations may be useful to distinguish generally-shaped cracks from volume defects. For elliptically-shaped cracks, we propose additional procedures that in principle allow the unique specification of crack size, shape an...

* Corresponding author; Email: [email protected] ABSTRACT Crack tunneling is a crack growth feature often seen in stable tearing crack growth tests on specimens made of ductile materials and containing through-thickness cracks with initially straight crack fronts. As a specimen is loaded monotonically, the mid-section of the crack front will advance first, which will be followed by crack growth ...

Acoustic emission (AE) testing was deployed on details of two large steel Interstate Highway bridges: one cantilever through-truss and one trapezoidal box girder bridge. Quantitative measurements of activity levels at known and suspected crack locations were made by monitoring AE under normal service loads (e.g., live traffic and wind). AE indications were used to direct application of radiogra...

We present a mechanistically faithful and mathematically sound approach to the numerical simulation of secondary thermal cracks propagation in EGS based on the variational approach to fracture [1-4]. While remaining compatible with classical theories, this approach provides a unified framework to crack nucleation, full path identification, including interaction between multiple cracks, branchin...