Rotura de um Cabo de Catamar？ Devido a Corros？o e Fadiga

the causes of failure of a gripping cable from a catamaran hull coupling bar were investigated. the 16 mm diameter single strand cable, composed of 19 stainless steel wires, was kept stretched through a threaded joint. fractographic macro examination of all wires facture surfaces and x-ray diffraction of exuded products collected inside the cable allowed the identification of a two step process failure: a first stage, where wires mainly from the outer layer of the cable suffered from interstitial and/or pitting corrosion, followed by slow crack propagation inwards wire section until complete rupture of most wires, due to fatigue and corrosion; and a second and last stage where final ductile rupture of the remaining wires, mainly from inner layer, occurred, due to overload. cracks nucleated inside crevices and pits, which was favoured by cable connecting ends design, exposition to sea water, fretting and applied stresses. a design revision was recommended.