Análisis a fatiga de las conexiones de un dique flotante mediante simulación numérica

Resum

Rubble-mound breakwaters and vertical caisson breakwaters are usually built to shelter port operations from wave action. If maritime weather conditions are moderate, modular floating breakwater are an economical alternative with less environmental impact. However, a high number of failures have been reported in these structures, mostly related to their weakest point: the connection elements between the modules. In this work, fatigue damage was investigated in the connections of a floating breakwater made up of five concrete pontoons anchored to the seabed by means of elastic ropes. The connections are composed of neoprene fenders that resists compression forces and stranded steel cables that resist traction forces. The analysis has focused on these last elements. The wave-structure interaction was numerically simulated in the time domain using a code based on the potential flow theory. The results allowed estimating the structural response under operational wave conditions. The cumulative fatigue damage was calculated using Palmgren-Miner's rule. The count of the stress cycles of each time series was carried out with the rainflow algorithm, and the S-N curve from the DNVGL-OS-E301 standard was considered. The results reveal that, for the wave conditions studied, in 30 minutes the wire ropes accumulate damage of approximately 0.0002% of their service life