The electrical discharge machining (EDM) process is mostly used in conditions that complex and intricate shapes need to be machined on very hard metals. However, the leaves behind some undesirable properties such as high surface roughness, rough topography, residual tensile stresses, micro-cracks, heat-affected zone (HAZ), recast layer. This paper investigates effects of different output parame...

The reason behind the majority of difficulties encountered in the integration of nanoscale objects with microelectromechanical systems can almost always be traced back to the lack of batch-compatible fabrication techniques at the nanoscale. On the one hand, self-assembly products do not allow a high level of control on their orientation and numbers, and hence, their attachment to a micro device...

Investigation of the tensile and fatigue properties of cast magnesium alloys, created by the heated mold continuous casting process (HMC), was conducted. The mechanical properties of the Mg-HMC alloys were overall higher than those for the Mg alloys, made by the conventional gravity casting process (GC), and especially excellent mechanical properties were obtained for the Mg97Y2Zn1-HMC alloy. T...

X-Ray Refraction Topography techniques are based on Ultra Small Angle Scattering by micro structural elements causing phase related effects like refraction and total reflection at a few minutes of arc as the refractive index of X-rays is nearly unity. The refraction contrast is several times higher than “true absorption” and results in images of cracks, pores and fibre debonding separations bel...

In this study,SGBEM Voronoi Cells (SVCs), with each cell representing a grain of the material at the micro-level, are developed for direct micromechanical numerical modeling of heterogeneous composites. Each SVC can consist of either a (each with a different) homogenous isotropic matrix, and can include micro-inhomogeneities such as inclusions, voids of a different material, and cracks. These i...

This paper addresses a method of non-intrusive local inspection of surface and sub-surface conditions, interfaces, laminations and seals in both space vehicle and ground operations with an integrated suite of imaging sensors during pre-launch operations. It employs an advanced Raman spectrophotometer with additional spectrophe tometers and lidar mounted on a flying robot to constantly monitor t...

Abstract In-situ three-point bending tests and finite element modeling based on the cohesive zone model were developed to study stress evolution cracking behavior of Cr coated Zr-4 alloy for accident tolerant fuel claddings. The initiation propagation micro-cracks captured by in-situ observation predicted numerical simulation. results showed that vertical cracks first initiated from coating sur...

A selection of surface crack problems is presented to provide insights into Stage I and early Stage II fatigue crack growth. Edge cracks at 45o and 90o to the surface are considered for cracks growing in single crystals. Both single crystal slip and conventional plasticity are employed as constitutive models. Edge cracks at 45o to the surface are considered that either (i) kink in the direction...

ID No: 136 Abstract: Cracks are inevitable for concrete infrastructures during their service life. The presence of cracks reduces the mechanical properties and bring potential safety hazard to infrastructure. In this study, the influence of self-healing on the ECC’s (Engineered cementitious composite) tensile properties was investigated. ECC is a new kind of HPFRCC, featuring high strain capaci...

* Corresponding author; Email: [email protected] ABSTRACT An important task in mixed-mode fracture analysis and prediction is the simulation of crack growth under mixed-mode conditions. To complete such a task, one must have (a) a computer code capable of handling the kinematics of general crack growth and determining the stress and deformation states during crack growth, and (b) a fracture crit...