基础环式基础连接旋转刚度的退化规律研究OACSTPCD

The damage to the ring foundation in a gravity-based foundation will reduce the anchoring stability between the foundation ring and the concrete base.Consequently,the wind turbine experiences significant tilting of the foundation ring during operation,which will adversely affect the operation safety of the wind turbine.Through monitoring tests on two wind turbines,considerable differences are observed in the foundation connection rotational stiffness between the two turbines.In order to understand the influence of different degrees of foundation damage on the foundation connection rotational stiffness,the finite element models of a 2.0 MW wind turbine foundation are established using ABAQUS for both intact and thirteen different damaged foundation scenarios.The results indicate that the rotational stiffness of foundation connection decreases with the enlargement of concrete void under the lower flange.Specifically,the rotational stiffness for the foundation with cracks penetrating through the foundation ring and concrete is 76.4%of the initial stiffness,while the foundation with a 15° void under the lower flange exhibits a rotational stiffness of 52.1%of the initial stiffness.The angles of the cavity within the range of 0°-15° and 30°-75° have a significant impact on the degree of degradation of the foundation connection rotational stiffness.Based on the observed degradation pattern of foundation connection rotational stiffness due to foundation damage,a method for evaluating the stability of wind turbine foundations is proposed.This method suggests using the foundation connection rotational stiffness in the ring foundation as a stability evaluation indicator for the ring foundation wind turbines.The method considers the foundation connection rotational stiffness after the wind turbine assembly as the initial value,providing a basis for comparing the subsequent foundation connection rotational stiffness of ring foundation wind turbines.