Mixed mode I/II stress intensity factors of an edge slant-cracked plate under tensile loading were assessed. A two-dimensional finite element analysis was employed using ABAQUS. Various crack lengths and angles were analyzed. The effect of the crack location at the plate edge was also examined. Crack initiation angles were calculated. In general, modes I and II stress intensity factor increase with increasing crack length. However, the rate of increase in mode I SIF decreases with increasing the main crack angle. The results showed that stress intensity factors decreased ad the crack mouth approaches the edge mid line. The crack location becomes more significant as the crack length increases. The angle of first cracking depends on crack length, location, and angle.
Glacial acetic acid as a protic acid was employed as a catalyst in a solvent free condition for facile preparation of di(indolyl)methanes (DIMs) via one-pot condensation of indole with aryl or heteroaryl aldehydes. Various aryl and heteroaryl aldehydes were efficiently converted to the corresponding di(indolyl)methanes (1a-p) in high yields. The described novel synthetic method proposes several advantages of safety, mild condition, short reaction times, high yields, simplicity and the inexpensively glacial acetic acid compared to other catalysts.
Mode I and mode II stress intensity factors (SIFs) through the thickness of edge crack in semi circular bend (SCB) and center cracked circular disc (CCCD) specimens have been analyzed using three dimensional finite element analysis. The effect of the CCCD and SCB specimen thickness on the through-thickness variations of SIFs has been studied. For all mode of mixity, the peak value of mode I SIF is found at mid plane of SCB specimen and for thin CCCD specimen, while, this location is shifted to be near the free surface plane in thick CCCD specimen. The variation of mode II SIF in CCCD and SCB specimens have a similar trend.