Solutions are presented for the elastic plane-strain problem of a crack in a coating on a compliant substrate of finite thickness. Analysis of the problem shows that substrate thickness has a significant effect on the steady-state energy release rate for channel cracks. This is so over a wide range of elastic mismatch between film and substrate, but is especially important if the substrate is m...

Corrosion-fatigue, a cracking mechanism in fossil-fueled generating plants, predominately occurs in the water walls and economizers of sub-critical plants. Cracking attributed to corrosion-fatigue has occurred in water wall tubing of both membrane and tangential designs. The occurrence (particularly in membrane water wall tubing) presents a challenge for nondestructive evaluation (NDE) because ...

The cracking resistance of Alloy 600, Alloy 690 and their welds, EN82H and EN52, was characterized by conducting JICtests in air and hydrogenated water. All test materials displayed excellent toughness in air and high temperature water, but Alloy 690 and the two welds were severeiy embrittled in low temperature water. In 54°C water with 150 cc Hz/kg H20, JICvalues were typically 70~o to !35Y0 ]...

Susceptibility of three lean-alloyed ferritic-austenitic stainless steels to hydrogen-induced delayed cracking was examined, concentrating on internal hydrogen contained in the materials after production operations. The aim was to study the role of strain-induced austenite to martensite transformation in the delayed cracking susceptibility. According to the conducted deep drawing tests and cons...

Ceramic matrix composites (CMCs) are currently being considered for applications in the hot-section components of aviation gas turbines owing to their favorable characteristics. Herein, a micromechanical modeling is presented orthogonal 3 D woven CMCs under in-plane loading. The three-dimensional effective compliance composite was derived using laminate theory and continuum damage mechanics. va...

While Portland cement concrete (PCC) overlay has been increasingly used as a rehabilitation technique for deteriorated PCC pavements in the last decade, reflective cracking places a major limit on its durability performance. The use of ultra ductile concrete named Engineered Cementitious Composite (ECC) should arrest such failure mode and greatly enhance the long term performance of the overlai...

The mechanical failure of three-dimensional (3D) 4-step braided SiCf/SiC composites, processed by precursor infiltration pyrolysis, has been studied under flexural loading to investigate the condition at failure. investigation integrated advantages continuous data acquisition optical imaging and 3D reconstruction internal structure in X-CT imaging, for situ microstructure-related mechanisms. Op...

Polypropylene (PP) makes up a large share of our plastic waste. We investigated the conversion PP over industrial Fluid Catalytic Cracking catalyst (FCC-cat) used to produce gasoline from crude oil fractions. studied transport limitations arising larger size polymers compared oil-based feedstock by testing components this separately. Infrared spectroscopy and confocal fluorescence microscopy re...

A non-destructive testing method on Glass Fibre Reinforced Polymer (GFRP) after high velocity impact event using single stage gas gun (SSGG) is presented. Specimens of Ctype and E-type fibreglass reinforcement, which were fabricated with 6mm, 8mm, 10mm and 12mm thicknesses and size 100 mm x 100 mm, were subjected to a high velocity impact with three types of bullets: conical, hemispherical and ...

Accurate, non-contact pH sensing is of particular importance in the biological and clinical sciences. Fluorescence lifetime based pH sensing is potentially more useful than intensity based methods because of the reduced sensitivity to excitation source intensity variations, scattering effects, and photobleaching. In this work, we investigate the variation of fluorescence lifetime with pH for re...