To better understand the relationship between the nucleation and growth of defects and the local stresses and phase changes that cause them, we need both imaging and stress mapping. Here, we explore how this can be achieved by bringing together synchrotron X-ray diffraction and tomographic imaging. Conventionally, these are undertaken on separate synchrotron beamlines; however, instruments capa...

Fatigue crack growth is examined in P/M 2124 aluminum alloys reinforced with SiC particles (SiCp) and whiskers (SiCw) over a wide spectrum of growth rates from 10 to 10 m per cycle. Effects of aging treatment, orientation of crack growth direction with respect to the rolling direction, mean stress (or stress ratio), and reinforcement volume percent on the fatigue crack growth threshold are inve...

As a first step towards a new crack healing methodology for cyclic loading, this paper examines two promising crack-tip shielding mechanisms during fatigue of a microcapsule toughened epoxy. Artificial crack closure is achieved by injecting precatalyzed monomer into the crack plane to form a polymer wedge at the crack tip. The effect of wedge geometry is also considered, as dictated by crack lo...

Fatigue crack growth is a complex process that involves interactions between many elements ranging across several length scales. This work provides an in-depth, experimental study of fatigue crack growth and the relationships between four of these elements: strain field, microstructure, crack path, and crack growth rate. Multiple data sets were acquired for fatigue crack growth in a nickel-base...

Button cutters are commonly used in hard rock drilling because the inserted carbide buttons provide exceptional wear resistance, impact and high strength challenging geological formations. One of most pressing issues designing a button cutter is to study breaking mechanisms buttons. In this study, three-dimensional discrete element method (DEM) was employed investigate mechanism cutting perform...

The failure of plasma-sprayed thermal barrier coatings (TBCs) during service is usually related to the cracking behavior. In this study, TBCs were prepared with two kinds agglomerated sintered yttria-stabilized zirconia (YSZ) powders different particle sizes. evolution mechanical properties and crack propagation behavior whole life stage studied by a shock test. effect powder size on was analyz...

Aqueous drops on silicone oil infused lubricating surfaces are cloaked with a thin layer of oil to minimize their surface energy. These oil cloaked aqueous drops exhibit pseudo-stable coalescence or spontaneous coalescence depending upon the lubricating oil thickness which controls the interaction point of the drops. For thick oil films, drops interact with each other through the surrounding oi...

In this paper an analytical crack propagation scenario is proposed which assumes that a crack propagates in the tooth root in both the crack depth direction and the tooth width direction, and which is more reasonable and realistic for non-uniform load distribution cases than the other presented scenarios. An analytical approach is used for quantifying the loss of time-varying gear mesh stiffnes...

Crack tip shielding phenomena, whereby the "effective crack-driving force" actually experienced at the crack tip is locally reduced, are examined with reference to fatigue crack propagation behavior in metals, composites and ceramics. Sources of shielding are briefly described in terms of mechanisms relying on the production of elastically constrained zones which envelop the crack (zone shieldi...

A new dynamical approach that combines covariant parton transport theory with hadronization channels via parton coalescence and fragmentation is applied to Au+Au at RHIC. Basic consequences of the simple coalescence formulas, such as elliptic flow scaling and enhanced p/π ratio, turn out to be rather sensitive to the spacetime aspects of coalescence dynamics. PACS numbers: 12.38.Mh; 24.85.+p; 2...