This document constitutes Deliverable ‘D6.2 Transportation and Maintenance LiftWEC ULS Assessment” of the LiftWEC project. LiftWEC is a collaborative research project funded by the European Union’s Horizon 2020 Research and Innovation Programme under Grant Agreement No 851885. It is the intention of the project consortium that the LiftWEC project culminates in the development of one or more promising configurations of a Wave Energy Converter operating through the use of one or more rotating hydrofoils that generate lift as the primary interaction with the incident waves.

In this report different scenarios for transportation and maintenance of LiftWEC are presented. It is the intention of this report to identify loading scenarios that occur in non-operating conditions (transport and maintenance) and that could risk the structural integrity of LiftWEC.

Up to this point, thirteen candidate LiftWEC configurations remain. As such, three configurations are here introduced: 1) supported with a monopile, 2) supported with a frame and 3) supported with a floater. The weight of the substructures of each configuration is computed considering a fixed water depth, hydrofoil span and radius.

It is to note that determining transportation and maintenance loads accurately is a significant challenge, hence here, some selected scenarios are presented as illustrative examples. This analysis has the aim to highlight critical areas of the structure that need to be considered during transportation and maintenance. The analysis is performed with Aqwa Ansys, Solid Edge, analytical methods and the online solver SkyCiv. Results are analysed in terms of structural integrity of the device.

It is worthy to note that a limit state is a condition beyond which a structure or a part of a structure exceeds a specified design requirement. For example, ULS can be defined as a condition where a loss of structural resistance occurs. Additionally, partial safety factors can be considered to account for abnormal operating conditions. As such, in this deliverable, we defined the threshold for the ULS as a fraction of the yield stress level. This threshold however can be refined to meet future design specifications.

The deliverable sets out the path to identify what additional measures need to be considered when transporting and maintaining LiftWEC from a structural perspective.