Weight Reduction Methodologies for Wave Energy Devices: A Structural Analysis Approach

The OE Buoy is a wave energy converter based on the Backward Bent Duct Buoy oscillating water column model which generates electricity through the fluctuation in wave height. Wave energy conversion devices are often faced with a particularly high levelized cost of energy (LCOE) when compared to other renewable energy devices, and various investigations into bridging this gap have been carried out in recent history. Previous studies on the OE Buoy have suggested that a significant reduction in required construction material is possible as a result of reduced differential pressures acting across the hull walls in operational conditions. Various structural analysis campaigns have been conducted on sections of the hull to assess this theory. A Finite Element Analysis (FEA) was performed on a full-scale model of the OE Buoy under maximum design wave loadings in operational conditions at EMEC’s Billia Croo test facility in Orkney, Scotland using Robot Structural Analysis software. A maximum pressure of 145 kPa was calculated for an 18.7 m peak wave height at Billia Croo. The OE Buoy was modelled for both static and dynamic load conditions under various constraint layouts. A modal analysis was conducted on the model which estimates the natural frequency of the OE Buoy to be approximately 6.67 Hz.