Damage Simulation And Damage Characterization Parameters Of Basic Ring Wind Turbine Foundation

China’s wind power industry has developed rapidly in recent years,but the various wind turbine foundation damage problems that have occurred in wind farms around China have caused huge economic losses to wind power companies.Under the action of repeated loads and large eccentric loads of the wind turbine foundation,stress concentration will occur in the concrete around the foundation ring,resulting in damage such as cracks and cavities in the foundation concrete.Therefore,studying the damage process simulation of the basic ring fan foundation has certain guiding significance to ensure the normal operation of the fan and the safety of the basic structure.Aiming at the problem of damage to the foundation of the basic ring fan,this article first compares the vertical offset of the basic ring obtained from the numerical simulation and the monitoring test to verify the accuracy of the numerical simulation and the monitoring test.Reuse finite element software to simulate the damage change process of the fan foundation,including the gradual failure of the fan foundation ring-foundation concrete bond,the foundation ring-concrete friction contact,the expansion of concrete cracks on the sidewall of the foundation ring,and the expansion of the concrete cavity at the flange under the foundation ring For these four gradual damage conditions,calculate and analyze the change law of the wind turbine foundation concrete stress and foundation ring displacement with the gradual damage of the foundation under each damage condition.The results show that:(1)With the decrease of the bonding height between the foundation ring and the concrete,the levelness of the fan foundation ring increases gradually,while the stress of the foundation concrete increases first and then decreases.The maximum levelness of the foundation ring does not exceed the allowable value of the specification.At this time,the fan foundation is still in a healthy condition.(2)Under the condition of friction between foundation ring and concrete,the stress of foundation ring distributes symmetrically along the direction of horizontal force.The maximum stress of foundation ring appears in the direction of horizontal load,and the stress on the compression side of foundation ring is greater than that on the tension side of foundation ring.The maximum stress of foundation concrete and steel grid appears around the lower flange on the tension side of foundation ring.By changing the load on the structure and the friction coefficient between the foundation ring and concrete,it is found that the stress of the foundation concrete and the vertical displacement of the foundation ring are positively correlated with the load,but negatively correlated with the friction coefficient.(3)As the cracks of the side wall concrete extend from the surface to the lower flange,the levelness of the foundation ring increases gradually,and the tensile stress of the foundation concrete increases gradually to close to the tensile strength of the concrete.The levelness of the foundation ring increases geometrically with the expansion of the foundation concrete cavity area.At this time,the maximum levelness of the foundation ring has far exceeded the levelness specified in the specification.