Thermomechanical damage analysis of pre-cooled wind tower foundations: experimental and numerical study

Abstract This study investigates the effectiveness and economic feasibility of five distinct pre-cooling methods for temperature control in mass concrete foundations of wind turbines. The methods combine liquid nitrogen (LN) and ice flakes to reduce hydration heat and minimize thermal cracking risks. Laboratory experiments using a semi-adiabatic calorimeter characterized the heat generation curves for each cooling strategy. These data were integrated into a three-dimensional finite element model (FEM) that simulates the thermal and mechanical behavior of the concrete foundation. The model was validated against field temperature measurements from an actual wind turbine base. Thermomechanical damage was assessed using Mazars’ continuous damage model implemented via a UMAT subroutine, focusing on compressive damage induced by thermal strains. Results show that LN cooling of aggregates provided the greatest reduction in peak temperature, lowering it from 67 ^ ∘ C (reference) to 48 ^ ∘ C, and significantly reduced damage at critical locations from 47% to 5%. However, this method also presented highest material cost, approximately seven times greater than ice flakes alone. The combined LN and ice flakes method achieved a balanced compromise, reducing peak temperature to 56 ^ ∘ C and damage to 14%, with moderate costs. All cooling methods except the ice flakes-only approach yielded higher compressive strengths than the reference. These findings underscore the trade-off between cooling efficiency, structural durability, and economic viability. The study contributes to optimizing thermal control strategies for large-scale mass concrete applications, highlighting the potential of LN-based cooling for improving foundation performance while recognizing cost considerations. Graphical abstract