Análise da integridade estrutural de conexões flangeadas em dutos flexíveis

Abstract

In this study some numeric technics were evaluated for the calculation of elastoplastic fracture mechanics parameter 𝐽 integral on pre-cracked flanged connections using finite element analysis. Resistance curves to the crack propagation were evaluated experimentally at room temperature (23°C) in metallic material AISI 4130, that is used in the fabrication of flanged connections. The material toughness was also evaluated at low temperatures (-20°C and -40°C) and the integral 𝐽 values at the instability point was obtained. The crack length during the tests was evaluated trough the unloading compliance technique using compact-tension C(T) test specimens. This study provided good results by using finite element on pre-cracked flanged connections in flexible pipes under tension and internal pressure, allowing an instability analysis using Crack Driving Force Diagrams. In addition, it allowed plastic collapse analysis of the flanged connections by comparison of the stress level and the yield strength of the material.