Burst Pressure Prediction of Multiple Cracks in Pipelines

N A Razak,N A Alang,M A Murad

doi:10.1088/1757-899x/50/1/012031

N A Razak, N A Alang + Show 1 more

Open Access

https://doi.org/10.1088/1757-899x/50/1/012031

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Abstract

Available industrial code such as ASME B1G, modified ASME B1G and DNV RP-F101 to assess pipeline defects appear more conservative for multiple crack like- defects than single crack-like defects. Thus, this paper presents burst pressure prediction of pipe with multiple cracks like defects. A finite element model was developed and the burst pressure prediction was compared with the available code. The model was used to investigate the effect of the distance between the cracks and the crack length. The coalescence diagram was also developed to evaluate the burst pressure of the multiple cracks. It was found as the distance between crack increases, the interaction effect comes to fade away and multiple cracks behave like two independent single cracks.

Highlights

Engineering structures such as aircraft, pressure vessels and piping may contained cracks like defects
Pipelines are normally subjected to a uniform internal pressure
While previous research provided promising method, the present paper predicts the burst pressure of collinear cracks and develops the coalescence diagram for pipeline steel

Summary

INTRODUCTION

Engineering structures such as aircraft, pressure vessels and piping may contained cracks like defects. For ASME B31G, the flow stress, Sf and bulging factor M is given by; L2 These codes concern about single defect, whereas the multiple crack like defect has a great potential to cause the structure to early fail. There are several methods for assessing the structural integrity of pipeline steel multiple cracks These include the body force method, the boundary element method and the finite element method (Moussa et al, 1999). Gonzales employed the condition where the critical lamination pressure defines as the pressure in the lamination that makes the von Mises stress in the interlaminar region to reach or surpass the ultimate strength of the material This condition is assumed to be the initiation point for the formation of the interconnecting cracks. While previous research provided promising method, the present paper predicts the burst pressure of collinear cracks and develops the coalescence diagram for pipeline steel. The effect of distance between crack and the crack length the main interest in this research paper

METHODOLOGY

CONCLUSION