Contact Mechanics of a Thin Layer Pressed Onto a Substrate by a Line Load

A fundamental plane frictional receding contact of a thin layer pressed onto a substrate is solved with the insertion of distributions of dislocations. The new formulation overcomes the restriction of standard contact analysis with the distributed dislocation technique, which requires the distributions to be square root bounded to zero or square root singular at the ends of the area of insertion. This new formulation opens up a range of plane frictional receding contacts to theoretical study. Solutions are obtained for the basic plane receding contact problem of a homogeneous linear elastic semi-infinite layer pressed by a line load onto a half-plane of the same material with a Coulomb friction interface. The frictional dependence of receding contact behavior is identified and discussed.

Evaluation of the Fatigue Strength of Notched Geometries Using a Microstructural Model and Generative Algorithms

In this work, the assessment of a short crack emanating from arbitrarily shaped notches under Mode I loading is done. A parametric algorithmic tool is used to create a wide range of different two dimensional notch shapes for the evaluation of notch fatigue strength by means of the Distributed Dislocation Technique. Comparisons between V-notches, U-notches and semi-elliptical notches establishing similar geometrical parametric relations are shown, so that the simplicity and versatility of the designed tool is demonstrated. This useful properties and advantages make this tool applicable to industrial problems such as the modelling and assessment of the effect of corrosion pits on fatigue strength.

Crack shielding in non-planar and frictional discontinuities under mixed-mode loading

In this paper, a two-dimensional model to describe the non-planar features of crack morphologies is presented. The model accounts for frictional tractions along the crack surfaces by considering an elastic-plastic-like constitutive interface law. Dilatancy effect due to crack roughness is described by the model, leading to a Mode I/II coupling between displacements and tractions along the crack surfaces. The non-linear solution of the rough and frictional crack under general remote scenarios is obtained using the Distributed Dislocation Technique (DDT). By considering a linear piecewise periodic profile of the interface crack, the influence of roughness and friction of interface cracks is examined in relation to both the resulting near-tip stress field and the fracture resistance under monotonic mixed-mode loading. The present model is able to quantify the increase of the fracture resistance due to roughnessand friction-induced crack tip shielding and to correlate it with a dimensionless crack size parameter.