In conventional WLCSP process, after defining the under bump metal (UBM) layer, a solder ball is dropped in the UBM opening. A subsequent thermal reflow cycle melts the solder ball and cools it in a well defined shape on top of the UBM layer. One draw back of this technology is the fracture or cracking of passivation film that may occur during the solder ball reflow process. The cracks in the p...

Cracking of laser hybrid welding of eccentric fillet joints has been studied for stainless steel. Laser hybrid welding enables narrow deep welds with freedom for shaping the upper weld geometry. The significance of geometrical aspects like weld toe radius, weld surface topography and lack of fusion on fatigue cracking is discussed. Constant amplitude four point bending tests, S/N-curve, topogra...

The paper presents a new analytical model to study the evolution of radial cracking around a corroding steel reinforcement bar embedded in concrete. The concrete cover for the corroding rebar is modelled as a thick-walled cylinder subject to axisymmetrical displacement constraint at the internal boundary generated by expansive corrosion products. A bilinear softening curve reflecting realistic ...

Tensile stress develops in concrete when shrinkage deformations and restraints (internal or external) exist. Utilization of appropriate creep or relaxation functions is crucial for assessing stress and the associated cracking potential in concrete, especially at early ages when chemical and physical properties change rapidly. The existing models, developed either from compressive creep tests or...

Machine learning models are built to predict the strain values for which edge cracking occurs in hole expansion tests. The samples from this test play role of sheet metal components be manufactured, often associated with a uniaxial tension stress state at critical edges components. For construction models, dataset was obtained experimentally rolled ferritic carbon steel sheets different qualiti...

two potassium oxalate doped tio2 samples, designated as k1-tio2 and k2-tio2, were synthesized by the base-catalyzed sol-gel process. these samples were impregnated into rubber sheets. two commercial tio2 samples, anatase and degussa p25, were used as reference materials with which the synthesized samples were to be compared. anatase and p25 were also impregnated into rubber sheets and designate...

in this paper, the effect of cyclic loading on punching strength of flat slabs strengthened with carbon fiber reinforced polymer (cfrp) sheets is studied. experimental results of ten slab specimens under monotonic and cyclic loading are analyzed. eight specimens were strengthened with cfrp sheets on the tensile face of the slabs and the two other specimens were kept un-strengthened as control s...

We conducted an exploratory investigation in an area where nut-cracking by wild capuchin monkeys is common knowledge among local residents. In addition to observing male and female capuchin monkeys using stones to pound open nuts on stone "anvils," we surveyed the surrounding area and found physical evidence that monkeys cracked nuts on rock outcrops, boulders, and logs (collectively termed anv...