Optimized tower wall material, a numerical investigation on timber laminates

Abstract

Traditionally, wind turbine towers have been constructed using steel and concrete. However, growing environmental concerns, particularly the need to reduce carbon emissions, have caused the search for alternative solutions across various sectors, including wind energy. One such solution is the use of laminated veneer lumber (LVL) as a sustainable material for wind turbine towers. A notable example is the Wind of Change tower, developed by Modvion, which stands 105 meters tall and is built from spruce LVL panels assembled with adhesives. This innovative approach reduces the environmental impact associated with traditional materials like steel and concrete, while still ensuring that the tower meets structural performance requirements. However, the need to optimize the design to reduce material usage while maintaining performance still arises. The aim of this thesis is to investigate whether an optimized tower design can achieve the same structural performance as existing solutions while minimizing material use. This is approached by designing two tower concepts and a benchmark model for a 166 meter tall wind turbine tower. Using Classic Laminate Theory (CLT), the study explores the effect of LVL panel orientations in different sections of the tower to identify an optimal orientation, referred to as the sweet spot angle, that maximizes safety factors under three defined load cases. The towers are evaluated against two failure criteria, Maximum Stress and Tsai-Hill, based on prior research correlating these criteria with the behavior of LVL wood. The investigation focuses solely on numerical simulations, with no experimental validation included in the scope. Results show that by optimizing the panel orientations, the total tower volume can be reduced by 15.4% while still meeting structural performance requirements.