A study is made of median crack evolution in brittle coatings subjected to sharp contacts. A model bilayer system consisting of a glass plate bonded to a polycarbonate base, with a Vickers pyramid as indenter, is used to demonstrate the evolution in situ. The cracks undergo a phase of stable downward growth with increasing load. Beyond the coating mid-plane, flexural stresses (coupled with the ...

Scaling laws arc the most fundamental aspect of every physical theory. Recently. the problem of scaling law and size effect in the theories of structural failure has received considerahle attention, particularly with regard to distrihuted damage and nonlinear fracture behavior. The paper presents a rigorous mathematical analysis of scaling in various types of failure theories in structural mech...

Unreinforced concrete pipes basically can fail in two modes: beam failure and ring failure. According to the existing test data, the nom· inal stress at beam failure is much less than that at ring failure. Fur· thermore, the nominal stress for either failure mode decreases as the pipe diameter or thickness increases. These size effects can be de· scribed in a unified manner by means of the rece...

The aim of the present paper is a systematic elab1 oration of a three dimensional finite element analysis tool for 2 discontinuous fracture in brittle solids. Brittle or quasi-brittle 3 fracture usually occurs when a material reaches the limit of its 4 strength and no plastic deformation has been observed prior 5 to failure. In the present approach, this kind of failure is char6 acterized by th...

Superplastic materials show a very high ductility. This is due to both peculiar process conditions and material intrinsic characteristics. However, a number of superplastic materials are subjected to cavitation during superplastic deformation. Evidently, extensive cavitation imposes significant limitations on their commercial application. The deformation and failure of superplastic sheet metals...

The propensity of the transition of fracture type in either brittle or ductile cracked solid under mixed-mode I and III loading conditions is investigated. A fracture criterion based on the competition of the maximum normal stress and maximum shear stress is utilized. The prediction of the fracture type is determined by comparing smax=rmax at a critical distance from the crack tip to the materi...

Deep earthquakes have been a paradox since their discovery in the 1920s. The combined increase of pressure and temperature with depth precludes brittle failure or frictional sliding beyond a few tens of kilometers, yet earthquakes occur continually in subduction zones to approximately 700 km. The expected healing effects of pressure and temperature and growing amounts of seismic and experimenta...