Modelling of a Flexible Inflatable Floater

Analysis of the stiffness behaviour of a drop-stitch panel for offshore floating photovoltaics

Master thesis (2022)

Authors

C. van Engelen Mechanical Engineering

Contributors

Lotfollah Pahlavan Ship Hydromechanics and Structures - Mechanical, Maritime and Materials Engineering (supervisor 1)
H.M. Verhelst Numerical Analysis - EEMCS (supervisor 1)
A.J.W. van den brink TNO (supervisor 1)
Martijn G. Hoogeland TNO (supervisor 1)
C.L. Walters Ship Hydromechanics and Structures - Mechanical, Maritime and Materials Engineering (supervisor 2)
A. Grammatikopoulos Ship Hydromechanics and Structures - Mechanical, Maritime and Materials Engineering (supervisor 2)
Faculty
Mechanical Engineering
Copyright: © 2022 Cas van Engelen
Thin-walled structures Floating Photovoltaics Failure behaviour Inflatable Wrinkling
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Published Date

11-03-2022

Language

English

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Faculty

Mechanical Engineering

Abstract

For floating photovoltaic systems, an uncommon type of offshore structure is considered, which is very flexible and deforms with the motion of the waves. In this research, the bending characteristics of a drop-stitch floater is analysed, which is an inflatable panel. By inflating the drop-stitch floater to a low air pressure, it obtains a flattened shape and the ability to support the flexible solar panels, while still retaining flexibility to deform with the motion of the waves. The bending characteristics of a drop-stitch floater are more complex than common offshore structures due to different non-linearities: wrinkling, hyperelastic material behaviour and internal pressure-volume work. Getting a better understanding in the bending response is important to eventually determine the response and limit states in offshore conditions. A finite element and experimental analysis has been performed of the response in a three point bending load case. Also, an experimental uniaxial tensile test has been performed to evaluate the hyperelastic anisotropic material behaviour. Different yarns spacings, internal air pressures and face sheet thicknesses are evaluated. This showed that there are two types of failure modes with distinct behaviour for an uniaxial pure bending load case: a global wrinkling and folding failure mode.