Acoustic Emission Monitoring Research Of Wind Turbine Blades During Fatigue Test

Wind energy as a clean and renewable energy,its development is attracting more and more attention,it will become one of the main energy resources necessary for the future survival of human society,the wind power industry has a broad and good development prospects.However,the safety of wind turbine blades is one of the important factors that affect the efficiency of power generation.Especially,the blades of wind turbines run more easily in the harsh environment,and they are more prone to accidents.Once the blade is seriously damaged,it is difficult to repair work,and greatly reduce the normal work efficiency of the wind turbine,but also cause enormous economic losses.Therefore,the monitoring of structural health in the wind turbine blade fatigue test plays a very important role in the safe operation of wind turbines.AE(Acoustic Emission)detection technology with passive and timeliness of detection characteristics,widely used in structural health monitoring of large components,and wind turbine blades,large volume and complex structure,structural health monitoring using acoustic emission technique of wind turbine blades plays a very important role in the fatigue test.On the basis of detailed understanding of the common quality problems of wind turbine blades and the development of acoustic emission technology at home and abroad,based on AE technology,the whole structure health test of wind turbine blade fatigue test was carried out,and the acoustic emission characteristics of composite materials under tension loading were analyzed.The acoustic emission characteristics of wind turbine blades under fatigue damage are studied and the damage evolution mechanism of composites is analyzed by acoustic emission technique.The main contents of the test including the attenuation of acoustic emission signals in wind turbine blades in the composite,a comparative analysis of the mechanical properties of the composites and the multi axial fiber and non fiber prejudge the acoustic emission characteristics of comparative analysis,and the size of wind turbine blades in the fatigue test process of acoustic emission application research.The experimental results show that the acoustic emission signal in the transmission process of wind turbine blade horizontal than vertical attenuation fast and large,and in the longitudinal and transverse propagation of the blade,the propagation distance is consistent with the signal amplitude and attenuation velocity,i.e.,as the signal propagates over the blade,the greater the distance,the greater the attenuation;The wind blade composite the tensile load and tensile modulus of prejudge fiber specimens lower without prejudge fiber specimens.a broken fiber signal energy is mainly concentrated in the low frequency range,including fiberprejudge specimens under tensile process of the acoustic emission signal showed the burst signal;mapping trend analysis is a simple spatial filtering technique can reduce the interference test environment,and The starting time and state of the damage can be well obtained by the trend analysis and mutual validation of the energy,RMS and other parameters.In different stages of fatigue vibration,the energy proportion of AE signals in the same frequency band is different,the damage propagation is more serious,The smaller the proportion of energy in the lower frequency band,the greater the proportion of energy in the high frequency band,which can characterization of the evolution degree of wind turbine blade damage.