Abstract

This work presents the development of two free Graphical User Interfaces (GUI), called ''FASTLognoter'' and ''MorisonForm'', both focused on the analysis of the behaviour of offshore structures, especially of offshore wind turbines. The first one is related to the aeroelastic analysis of wind turbines, and the second is concerned with the seakeeping of marine structures. The development of these tools has been carried out using a powerful software called ''Lognoter''. This tool is free software for Knowledge Management in Technology (KMT), which integrates computer programming for allowing the development of GUIs. These GUIs give an open platform for conducting a parametric study of the structural and dynamic behaviour of marine structures. Their coupling permits the user to set a suitable way to evaluate new concepts in marine structures. Finally, an application for the intensive analysis of offshore wind turbines is shown.

Abstract

This paper deals with the numerical modelling of rigid blocks by means of a rigid body spring model (RBSM). The hypothesis of small rotations has been considered in order to simplify the mathematical formulation. The asymmetric rocking motion is described. Extensive numerical simulations have been carried out in order to validate the numerical model, as well as to study the dynamical behaviour of asymmetric rigid bodies. The maximum response depends on the type of asymmetry and the direction of the load, which should become new variables in the study of asymmetric rocking motion.

Abstract

In this work, the influence of the loading rate on the mode I interlaminar fracture toughness of carbon fiber laminates manufactured with prepregs of the second (IM7/8552) and third generation (IM7/M91) was investigated. The study has been carried out using to loading rates ranges, namely, quasi-static between 0.5 and 450mm/min, and dynamic between 100 and 2000mm/s. The latter tests were performed using a Gleeble 3800GTC hydraulic testing system. The dynamic tests were carried out using the WIF methodology (wedge insert fracture) by inserting at high speed a cylinder between the arms of the specimen. Two strain gauges were used to measure the maximum flexural deformation of the loading arms allowing the estimation of the opening force of the specimen to infer the dynamic fracture energy. The results showed that the IM7 / M91 laminate was sensitive to the speed of solicitation presenting a maximum value of the fracture energy for 500mm/s being the toughness more than twice than the one measured under quasi-static conditions.