| Wind energy is a clean and renewable energy source.Wind power generation is the main way to make rational use of wind energy.In today’s renewable energy,the technology of water removal technology has the highest maturity and the largest scale.The same development conditions are also at the top of the industry.Great value.In recent years,the national policy has been continuously improved,the wind power industry has developed rapidly,and the development of technology has become more mature.The rated power,overall weight,cabin height,foundation depth and blade size of the wind turbine have been increasing with the development.This requires strict requirements for the overall stability of the fan.Offshore wind turbines are mainly subjected to the vibration of reciprocating and random wind loads during their 20-year lifespan.On this basis,they bear irregular wave loads,and the mechanism of the failure of the wind turbine foundation is more complicated,while the steel metal is Under the action of direct continuous repeated dynamic loads and irregular wave loads,due to the accumulation of damage of the metal material and the erosion of the seawater by the foundation,there will be sudden signs of brittle fracture without warning.Although the damage and damage of the structure under fatigue load is not as obvious as the brittle failure under the action of storm,it is a long-term process,which is more harmful to the structure of the wind turbine.Therefore,this paper takes the existing engineering examples as the background and the sea.The fan performs the force analysis of the random dynamic cyclic load and evaluates the fatigue reliability of the basic dangerous node.The main research contents are as follows:1.Simplify the structure of offshore wind turbines.Establish a three-dimensional model including the tower-blade-pile foundation-foundation,analyze the modality of the fan,understand the natural vibration characteristics of the structure,and check whether the fan avoids the frequency of resonance and meets the safety requirements.2.The stochastic process of wind speed fluctuation is expressed as a finite sum of the deterministic time function and the corresponding uncorrelated random coefficient by the orthogonal expansion method.The above workload is realized by using Matlab programming,generating random wind speed time history at different times,and calculating the wind load time history acting on the wind power generator.3.Through the random function expression of standard orthogonal random variables,the simulation of random ocean wave process is realized,and the standard orthogonal random variable is expressed as a functional form of a basic random variable.The same calculationwork is also implemented by Matlab programming,the simulation of the random wave is completed,and the stress acting on the wind turbine is calculated,and the calculated wind load stress time history is synthesized to obtain the combined total stress.4.Matlab programming is carried out on the rain flow counting method,and the hysteretic stress rain flow count of the stress time history calculated by the dynamic response is obtained,and the obtained calculation result is further subjected to stress correction,and substituted into the linear accumulation theory of fatigue damage,combined with the steel metal Applicable SN curve,using Matlab programming to calculate the fatigue damage of the fan foundation.5.Using the probability density evolution method,construct the virtual time process with the fatigue damage value,and the initial specified probability obtained by the number theory selection point is brought into the probability density evolution theory for numerical calculation,and the fatigue damage is calculated by Matlab programming and numerical method.The numerical solution of the evolution probability density is based on the fatigue theory,and the fatigue density of the structure is obtained by integrating the probability density of the fatigue damage value below 1. |
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