A design tool for flexible wave energy converters based on SPH

Commercialization of wave energy faces persisting bottlenecks due to the limited performance of Wave Energy Converters (WECs), leading to high manufacturing and investment costs. A promising approach to overcome these challenges involves the integration of flexible materials into WEC designs. In contrast to traditional rigid structures, flexible WECs (flexWECs) offer several key advantages. Firstly, such devices better adapt to dynamic wave loads, potentially improving energy capture and reducing fatigue. Besides, the potentially unlimited numbers of modes of vibration offer a wide spectrum of optimal operational frequencies. FlexWECs, moreover, can accommodate innovative energy conversion technologies like Dielectric Elastomer Generators (DEGs), enabling more efficient and potentially lower-cost energy harvesting. However, flexWECs need to still endure a refinement process that can be greatly sped up by numerical tools. Given that flexWECs consist of compliant structures interacting with fluid masses, often under resonant conditions or extreme sea states, a robustly coupled solution for the hydroelastic problem is critical for accurately predicting the loads and behavior of these devices. As such, the Smoothed Particle Hydrodynamics (SPH) method holds great potential, as its most valuable features for engineering applications are precisely related to extreme deformations, violent flows, and inherent treatment of fluid–solid boundaries in dynamic conditions. This work presents a novel, high-fidelity numerical model for simulating flexWECs, leveraging the strengths of the open-source DualSPHysics [3] and Chrono [4] solvers. In such a framework, a lumped parameter discretization is implemented to cope with mono- and bi-dimensional compliant elements (beams and plates, respectively). The flexible structure modeling relies on co-rotational dynamics to solve high-strain/deformed states, achievable leveraging the multi-body Chrono solver and properly linear elastic constitutive models. The application of the developed framework to simulate flexWECs, particularly a modified FOSWEC concept [5], demonstrates its practical relevance for advancing wave energy technology