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Rock is a natural brittle material, and under compressive stresses fracture and failure occur by initiation, growth and interaction of microcracks forming macroscopic cracks and finally leading to a fault. As stress vs. volumetric strain curve can give only qualitative results, both for understanding the phenomenon of fault formation in terms of microcracking stages quantitatively and also for accurate prediction of impeding failure it becomes essential to identify the stages of the stress vs. volumetric strain curve by a suitable technique. Thus, in this respect the advantages of acoustic emission, a real-time on-line monitoring technique, is investigated. Conventionally, plots based on cumulative events, event rate and amplitude distribution are used to understand crack growth. while these parametric plots give the trends in terms of their AE activity, the exact characteristics of events in relation to the phenomena at different stress levels of micro and macro crack progression to failure are not easily discernible. So, in the present work based on the recorded wave form parameters, events are classified into four groups as α, β, γ and δ and are characterized as micro and macro crack phases which correlate with ultrasonically imaged data. Classification of events into micro and macro crack phases gives a better understanding of fault formation in rock materials and also the effect of stress, temperature, macrostructure, mineralogy, etc.

Abrasive waterjet cutting is superior to many other non-traditional machining processes in processing variety of materials, particularly difficult-to-cut materials and has found extensive applications in industry. This paper assesses the influence of process parameters on depth of cut which is an important cutting performance measure in abrasive waterjet cutting of mild steel. Experiments were conducted in varying water pressure, nozzle traverse speed, abrasive mass flow rate and standoff distance for cutting mild steel using abrasive waterjet cutting process. The effects of these parameters on depth of cut have been studied based on the experimental results. In order to correctly select the process parameters, an empirical model for the prediction of depth of cut in abrasive waterjet cutting of mild steel is developed using regression analysis. This developed model has been verified with the experimental results that reveal a high applicability of the model within the experimental range used.

The objective of this paper is to perform analysis and optimization of the critical component of Check Valve, its Body or Housing. Housing is mainly prone to its internal fluid pressure which passes through it. Circumferential Shell thickness of the Check valve housing is an important factor which decides the life of the valve. Wall thickness maintained should be an optimized one, else more thickness will lead to cost implication and less wall thickness will lead to failure of the vessel. Based on the ASME Standards, Check Valve body is categorized as a Pressure Vessel which contains only internal pressure. This project set out to verify finite element analysis, or FEA, when applied to Check Valves. In this study, we carried out the structure analysis of the body of the Check valve using ANSYS v14.5. Validation of the FEA results is supported by stress analysis using classical theory of mechanics. Numerically calculated stresses are compared with the FEA results and the Wall thickness is finalised based on it. Having tested three dimensional symmetric models, the preliminary conclusion is that the FEA is an extremely powerful tool when employed correctly.to the original impeller.