Fatigue Crack Growth Behavior in Dissimilar Metal Weldment of Stainless Steel and Carbon Steel
Constant amplitude fatigue crack growth (FCG) tests were performed on dissimilar metal welded plates of Type 316L Stainless Steel (SS) and IS 2062 Grade A Carbon steel (CS). The plates were welded by TIG welding using SS E309 as electrode. FCG tests were carried on the Side Edge Notch Tension (SENT) specimens of 5 mm thickness, with crack initiator (notch) at base metal region (BM), weld metal region (WM) and heat affected zones (HAZ). The tests were performed at a test frequency of 10 Hz and at load ratios (R) of 0.1 & 0.6. FCG rate was found to increase with stress ratio for weld metals and base metals, where as in case of HAZ, FCG rates were almost equal at high ΔK. FCG rate of HAZ of stainless steel was found to be lowest at low and high ΔK. At intermediate ΔK, WM showed the lowest FCG rate. CS showed higher crack growth rate at all ΔK. However, the scatter band of data was found to be narrow. Fracture toughness (Kc) was found to vary in different locations of weldments. Kc was found lowest for the weldment and highest for HAZ of stainless steel. A novel method of characterizing the FCG behavior using an Infrared thermography (IRT) camera was attempted. By monitoring the temperature rise at the fast moving crack tip region, the amount of plastic deformation was estimated. Keywords—Dissimilar metal weld, Fatigue Crack Growth,
ASSESSING THE SIGNIFICANCE OF FLAWS IN WELDS SUBJECT TO FATIGUE
The substitution of fracture mechanics crack propagation data for simple S-N curves provides additional data on welds defects, other than applied stress and the influence of geometry. It allows the fatigue process to be entered (variation in initial flaw size) and left (variation in failure criterion) at will and variations in geometry and crack share to be taken into account. The value of the method has been confirmed by accurately predicting the fatigue behavior of fillet welds containing flaws on the basis of the generalized stress parameter.
Exploring interculturally competent teaching in social sciences classrooms
Abstract This paper explores a grounded research-based framework for intercultural competence and discusses the implications of interculturally competent teaching in the classroom and beyond. Given the importance of teachers being interculturally competent in today’s diverse classrooms, a number of questions, based on the framework, are presented, which guide teachers in reflecting upon their own teaching practice and the ways in which they integrate aspects of intercultural competence into their classrooms. The paper also provides some examples from the USA of ways in which intercultural competence development is being addressed in teacher training.