Modelo matemático multivariante para estimar el valor CTOD en función de propiedades mecánicas, químicas y microestructurales aplicado a uniones soldadas para la industria Offshore

Abstract

The increasingly mechanical requirements of the offshore structures have established the relevance of fracture mechanics-based quality control in welded joints. For this purpose, CrackTip Opening Displacement (CTOD) at a given distance from Crack-tip has been considered one of the most suited parameters for modelling and control of crack growth and is it broadly used at the industrial level. We have modelled through multivariate analysis techniques the relationship among CTOD values and other material properties (as hardness, chemical composition, toughness or microstructural morphology) in high-thickness offshore steel welded joints. In order to create this model, hundreds of tests were done in 72 real samples welded with a wide range of real industrial parameters. The results obtained have been processed and evaluated with different multivariate techniques, and we have established the significance of all the chosen explanatory variables and the good predictive capability of the CTOD value within the limits of the experimental set variation. By establishing the use of this model, significant savings are achieved in the manufacturing of wind generator as CTOD tests are more expensive and complex than the proposed alternatives. Besides, this model allows for some technical conclusions.