a method based on electrical capacitance tomography (ect) and an improved least squares support vector machine (ls-svm) is proposed for void fraction measurement of oil-gas two-phase flow. in the modeling stage, to solve the two problems in ls-svm, pruning skills are employed to make ls-svm sparse and robust; then the real-coded genetic algorithm is introduced to solve the difficult problem of ...

Recent experiments have shown that fracture surfaces of bulk metallic glasses (BMGs) usually exhibit an intriguing nanoscale corrugation like fractographic feature mediated by nanoscale void formation. We attribute the onset of this nanoscale corrugation to TTZs (tension transformation zones) mediated cavitation. In our recent study, the spall experiments of Zr-based BMG using a single-stage li...

The process of fracture in ductile metals involves the nucleation, growth, and linking of voids. This process takes place both at the low rates involved in typical engineering applications and at the high rates associated with dynamic fracture processes such as spallation. Here we study the growth of a void in a single crystal at high rates using molecular dynamics (MD) based on Finnis-Sinclair...

Experimental damage mechanics of flip chip solder joints under current stressing is studied using 20 test vehicle flip chip modules. Three different failure modes are observed. The dominant damage mechanism is caused by the combined effect of electromigration and thermomigration, where void nucleation and growth lead to the ultimate failure of the module. It is observed that thermomigration dri...

Aneurysm growth is accompanied by formation of intraluminal thrombus. The onset of thrombus rupture via unstable void growth is studied in the present note. The experimentally calibrated constitutive model of thrombus developed by Wang et al. (2001) is enhanced with a failure description and used for analysis of cavitation. It is found that unstable cavity growth can start at hydrostatic tensio...

The intergranular crack propagation of the lamellar structure β titanium alloys is investigated by using a modified Gurson-type damage model. The representative microstructure of the lamellar alloy, which consists of the soft α phase layer surrounding the hard grain interiors, is generated based on an advanced Voronoi algorithm. Both the normal fracture due to void growth and the shear fracture...