Per: VICTOR BARBOSA DE SOUZA (UFF / UENF / UNIREDENTOR), Kayan Afonso Carneiro (UFF / UENF / UNIREDENTOR), Lucas Souza Costa (UFF / UENF / UNIREDENTOR), Amanda Camerini Lima (UFF / UENF / UNIREDENTOR)
Abstract:
Nowadays the metal structures have a wide range of applications, being used for the construction of bridges, stadiums, sheds, oil rigs, airports, silos, deposits, among other numerous applications. In most cases, these types of structures have large size and suffer great efforts, so they are subject to failure. The fracture mechanics is a science where it studies the behavior of a certain flaw, the crack. Therefore, the present work was aimed at analyzing the behavior of cracks in steel structures, more specifically on a pedestal of an offshore crane manufactured in ASTM A-36 steel. To accomplish such a feat was necessary the metallographic assay and mechanical traction assays following the ASTM A-370 standard, and fracture toughness according to the British Standard-7448, development of a mathematical model for the pedestal according to mechanics classical, calculation of the criticality of three types of cracks being they, surface, through-thickness and embedded with the support of the British Standard-7910 and the calculation of the growth estimation of cracks. The entire methodological procedure of the work allowed the characterization of the microstructure of the material, determination of the mechanical properties of the material, the fracture toughness of the steel, the mechanical efforts that work on the pedestal, the criticality of the cracks and the maximum dimensions that the cracks will have to bring the structure to the collapse. The surface flaw obtained the largest dimensions for the collapse of the structure, being 22.2 mm deep and 88.83 mm in length. The through-thickness flaw has had the smallest dimension for the collapse, with a length of 63.67 mm. The embedded flaw presented dimensions of 24.99 mm in width and 66.015 mm in length. However, the cracks in their initial dimensions did not present any risk to the structures, however, the study was able to determine the maximum size that the cracks can achieve, being possible estimate the useful life of the element.
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