Caracterização da superfície de fratura gerada por fadiga em soldas subaquáticas molhadas

Abstract

Three-dimensional reconstruction of surfaces has been widely used in the field of materials fracture due to the need of better understand the phenomena related to this process and the mechanisms that lead to the material failure. Fatigue fracture surfaces in wet underwater welds were then characterized by means of three-dimensional reconstructions using stereophotogrammetry in a scanning electron microscope. This work proposes, therefore, the development of a methodology to characterize the fatigue fracture surfaces of underwater wet welds. Samples of welds have been selected in order to evaluate the effect of different porosity populations and also the effect of the mechanical response caused by the fatigue tests. For this purpose, profile, roughness and fractal dimension analyses were carried out. It could be seen the areal roughness parameter Sq as more effective than the fractal dimension to describe and compare the studied surfaces. In addition, it was possible to endorse the pertinence of the used technique and the developed methodology for the proposed study. Nevertheless, it is stated that further study is required in order to fully understand the mechanisms of fatigue crack propagation in wet underwater welds