Towards Reliability-Based Geometry Optimization of a Point-Absorber with PTO Reliability Objectives

In this study, we seek to understand the relationship between wave energy converter (WEC) hull geometries and power take-off (PTO) reliability. To do this, we calculate the damage equivalent loads (DELs) for a PTO given three hull shapes (a cylinder, a sphere, and a barge), two sets of metocean conditions (from the center of the North Sea and off the west coast of Norway), and two float motions (heave and surge). Results indicate that hull geometry has a primary influence on DELs experienced by the PTO, and also that certain geometries result in larger variations in DELs based on whether the device is moving in heave or surge motion. These findings underline the importance of considering WEC hull geometry in early design processes to optimize cost, power production, and reliability. More importantly, this research emphasizes the need to consider the relationship between the WEC geometry and the PTO reliability early in the design process. By considering this relationship, more optimal WECs can be designed for power production and system reliability. The methods tested in this study will enable the future reliability-based geometry optimization of WEC hulls to maximize reliability and power production.