Numerical Investigations of Damage Behaviour at the Weld/Base Metal Interface

In the present paper, the numerical modelling to predict the interface damage of weld defect in a steel pipeline was studied. This work focused on determination of the maximum operating pressure and the characterisation of mechanical behaviour at a weld-base metal interface. The operating pressure can fluctuate leading to the phenomenon of fatigue and consequently to the failure of pipeline. Experimental investigations were carried out using non-destructive test (NDT) in order to locate and determine size of defects. A bilinear interface decohesion model is used to simulate the damage behaviour considering a stress-relative displacement laws. Numerical simulations based on the finite element method were used to study the influence of size defects and young's moduli ratio on the operating pressure as well as interfacial damage between the weld and base metal. The obtained results showed that the interface damage depending on shape and material properties of defects has an impact on pipeline safety and integrity.