Experimental and computational analysis of ovality effect in a standalone pipe bend

Abstract

Pipe bends construct an integral part of any piping system in the industrial field. During an industrial operation does happen. Catastrophic failures in the extrados of pipe bend is identified. It is very essential to identify the potential cause of such a failure and to provide a suitable solution by considering the minimum design requirements. Significant researches have been carried out on the subject of construction of an integrity assessment for pipe bends using both analytical and experimental approaches. Many researches were focused on handling the problem of pipe bends with uniform cross section. This study focuses on an oval cross section. It is difficult to avoid thickening and thinning on the inner and outer radius of the pipe during the manufacturing of inlet pipe bends. The cross section of the bend becomes non circular and the non-circular cross section acceptability is based on the induced level of shape irregularity. Moreover, In most of the investigations, the geometric shape (ovality) and its effect due to various loding conditions have not been subjected to thorough investigation. Hence it requires a detailed investigation which has been carriedout the present work. The pipe bend characteristic mainly depends on curved geometry and higher flexibility. The additional flexibility is also accompanied by stresses and strains which are much higher than the value present in a straight pipe of same size and material, under the same loading conditions. For designing of a pipe bend, it is useful to have a reliable estimate of their loadcarrying capacity along with a deep understanding of their structural behavior, under different loading conditions.The effect of ovality in pipe bend region is the primary objective of this study. Finite Element Analysis (FEA) has been performed for different pipe bend geometry process using ANSYS-work bench. Experimental evaluation was carried out for validating FEA results. A pipe with 90° bend geometry along with attached straight pipe was considered for the study. Analyses were performed by varying the percent of ovality (Co) between 0 and 20. The study was carried out considering (a). Pure internal pressure (b) pure bending and (c) Combined internal pressure and in-plane bending for various r/t values ranging from 10 - 50. newline