Análise de confiabilidade estrutural de tubos de materiais compósitos submetidos à pressões uniformes

Abstract

In recent years, the search for materials with better mechanical performance has led to increased research and development of composite materials, with emphasis on reinforced materials by unidirectional long fibers. These materials have been highlighted because of its high stiffness=weight and strength=weight ratios, and excellent resistance to fatigue and corrosion.The good mechanical performance of these materials has allowed its use in pipes production that may be subjected to high pressure and severe environmental conditions. For example, it can be cited its use in risers in the offshore industry, replacing steel. Because of the difficulties in assessing the effective properties of these materials, due to heterogeneity and anisotropy of them, it is recommended the use of homogenization techniques and multiscale modeling strategies. In this work, its proposed the use of the Generalized Self-Consistent Model to obtain the effective elastic properties of the laminas that constitute the laminate of the pipe wall. These properties are used on the analysis of composite laminate tubes, satisfying kinematic constraints tipically imposed for thin-walled tubes and employing the Classical Lamination and Linear Instability Theories, enabling assessment of critical external pressure, which can cause buckling in the tube, and external hydrostatic pressure that would cause the pipe failure, based on the Tsai-Hill failure criterion. Reliability analyses are performed via Monte Carlo Method, in order to perform reliable assessments of sensitivity with respect to the parameters defining the pipe configuration, with emphasis on those that can be controlled during the manufacturing process.