Analysis Of New Piezoelectric Component Applied To Crack Location Of Wind Turbine Blade

Wind turbine blade is prone to structural damage under complex alternating loads all the year round,which will cause safety accidents and property losses in serious cases.Therefore,it is of great significance to detect the structural damage existing in the wind turbine blade in a timely and efficiently.Using the damage location technology of Lamb wave,the real time and online detection of wind turbine blade crack can be realized.For the damage location technology of Lamb wave,lamb wave need to be excited by piezoelectric component.However,the traditional piezoelectric component has a small driving performance,which requires multiple piezoelectric components arrays to be used.The piezoelectric component is isotropic in the plane.The energy of the stimulated Lamb wave signal is dispersed throughout the region,and the redundant signal is received by the sensor,which cannot highlight the characteristic signal.Increasing the difficultly of locating the crack in the wind turbine blade.In this paper,a cross-ring electrodes piezoelectric component is designed to solve the problem that the exciting component cannot provide high free strain and clamping stress in the plane in the damage detection technology of Lamb wave.Based on the piezoelectric equation,the output equations of radial clamping force and free displacement of cross-ring electrodes piezoelectric component are established.The electric field analysis and static analysis of the piezoelectric component are analyzed by ABAQUS software to determine its poling voltage and static mechanical properties.The analysis results show that the poling voltage of the piezoelectric component with cross-ring electrodes is 1/3 of that of the piezoelectric component with common electrodes,which realizes the poling of the piezoelectric component with low voltage.The radial clamping force of the cross-ring electrodes piezoelectric component can reach 2.6 times of that of the traditional common electrodes piezoelectric component,and the radial free displacement can reach 2.8 times of that of the common electrodes piezoelectric component,achieving large displacement and force output in the plane.A local ring electrodes piezoelectric component is designed to generate stress waves in the plane of piezoelectric component and improve the accuracy of crack location.Its static analysis was carried out to study the influence of the structural parameters of electrodes on its static mechanical properties.The analysis results show that the radial clamping stress of the electrodes area of the local ring electrodes piezoelectric component can reach 12.2 times of that in the non-electrodes area,and the radial free strain of the electrodes area reaches 2.6 times of the non-electrodes area.It shows local ring electrodes piezoelectric component has obvious orthotropic anisotropy in the plane and the stress wave can be directionally generated.Reduced the center distance of the branch electrode,increased the electrode width and reduced the thickness of the piezoelectric actuator,which is beneficial to improve the static mechanical properties of the electrodes area of the local ring electrodes piezoelectric component.The finite element model of the surface crack location of wind turbine blade is established by using ABAQUS software,Lamb wave was excited by local ring electrodes piezoelectric component and the surface crack of wind turbine blade at different positions are located by detection technology of baseline-free Lamb wave.The relative errors between the surface crack positions obtained by simulation analysis and actual surface crack positions are(6.5%,4.6%),(5.0%,4.2%)respectively The results show that the baseline-free Lamb wave damage location technology can accurately locate and image the surface cracks of wind turbine blade,and the imaging effect is more intuitive and clear.