Oceans are harsh environments and can impose significant
loads on deployed structures. The deployment of wave energy converters (WECs) faces a design challenge with apparently contradictory goals. A WEC should be designed to maximize the energy absorbed while ensuring the operating wave
condition does not exceed the failure limits of the device itself. Therefore, the loads endured by the support structure are
a design constraint for the system. Adaptability to different sea
states is, therefore, highly desirable. This work uses a WECSim model of a variable-geometry oscillating wave energy converter (VGOSWEC) mounted on a support structure simulated
under different wave scenarios. A VGOSWEC resembles a paddle pitching about a fixed hinge perpendicular to the incoming
wave fronts. Therefore, the hinge experiences loads perpendicular to its axis as it maintains its position. The geometry of the
VGOSWEC is varied by opening a series of controllable flaps
on the pitching paddle when the structure experiences threshold
loads. Because opening the flaps lets the waves transmit through
the paddle, it is hypothesized that opening the flaps should result in load shedding at the base of the support structure. The
load shedding is achieved by reducing the moments about the
hinge axis. This work compares the hydrodynamic coefficients natural periods, and response amplitude operators from completely closed to completely open configurations of the controllable flaps. The comparisons quantify the effects of letting the
waves transmit through the VGOSWEC. This work shows that
the completely open configuration can reduce the pitch and surge
loads on the base of the support structure by as much as 80%. It
was observed that at the paddle’s resonance frequency, the loads
on the structure increased substantially. This increase in loads
can be mitigated by a rotational power take-off damping about
the hinge axis. Changing the rotational power take-off damping
was identified as an additional design parameter that can be used
to control the loads experienced by the WEC’s support structure.
