Thermo-mechanical reliability of the solder bumped flip chip packages having underfill encapsulant was evaluated with thermal shock testing. In the initial reaction, the reaction product between the solder and Cu mini bump of chip side was Cu6Sn5 IMC layer, while the two phases which were (Cu,Ni)6Sn5 and (Ni,Cu)3Sn4 were formed between the solder and electroless Ni-P layer of the package side. ...

An experimental investigation into the fracture properties of 160-lm-thick edge-cracked specimens of austenitic nickel–titanium (nitinol) under uniaxial tension is presented. Using the in situ optical technique of digital image correlation (DIC), strain fields directly relating to phase boundary nucleation and propagation of fracture samples were observed for the first time. The shape and size ...

In this paper, 2D boundary element stress analysis is carried out to obtain the T-stress for multiple internal edge cracks in thick-walled cylinders for a wide range of cylinder radius ratios and relative crack depth. The T-stress, together with the stress intensity factor K, provides amore reliable two-parameter prediction of fracture in linear elastic fracture mecha...

We study the mechanics of pull-off of a barnacle adhering to a thin elastic layer which is bonded to a rigid substrate. We address the case of barnacles having acorn shell geometry and hard, calcarious base plates. Pull-off is initiated by the propagation of an interface edge crack between the base plate and the layer. We compute the energy release rate of this crack as it grows along the inter...

An integral transform technique is used to solve the elastodynamic problem of a crack of fixed length propagating at a constant speed at the interface of two bonded dissimilar orthotropic layers of equal thickness. Two cases of practical importance are investigated. Firstly, the lateral boundaries of the layers are clamped and displaced in equal and opposite directions to produce antiplane shea...

The visual examination of downstream faces of hydro dams is an important component in their monitoring. Few computer vision algorithms exist for this task. Some of them aim to detect and evaluate concrete cracks using edge detection. Other problems can also affect hydro-dams, as roughness, scratches, and can lead in time to surface deterioration. These are not currently reliably addressed by im...

This paper considers the explicit solutions of free-edge stresses near circumferential cracks in surface coatings of circular torsion bars and their application in determining the progressive cracking density in the coating layers. The problem was formulated within the framework of linear elastic fracture mechanics (LEFM). The free-edge stresses near crack tip and the shear stresses in the cros...

Because of the awkward and somewhat irregular shape of the weidment, conventional methods [I] could not be adapted to the nondestructive measurement of GT A W edge weid penetration on clamshell-style catalytic converters and a special inspection system based on the eiectric current deflection method was developed. DC or low-frequency AC electric resistance measurements, also known as the Potent...

In this article, the size effect on the dynamic behavior of a simply supported multi-cracked microbeam is studied based on the Modified Couple Stress Theory (MCST).  At first, based on MCST, the equivalent torsional stiffness spring for every open edge crack at its location is calculated; in this regard, the Stress Intensity Factor (SIF) is al...

ÐThe high-temperature fatigue-crack propagation and fracture resistance of a model g-TiAl intermetallic composite reinforced with 20 vol.% ductile b-TiNb particles is examined at elevated temperatures of 650 and 8008C and compared with behavior at room temperature. TiNb reinforcements are found to enhance the fracture toughness of g-TiAl, even at high temperatures, from about 12 to 040 MPa m, a...