Wind Turbine Composite Material Blade Structural Stress Analysis And Health Monitoring

Blades are the most critical parts in the wind turbine. its structure and force are quite complicated, it is the most vulnerable location to wind turbine. Therefore, a very effective way to ensure the safe operation of wind turbines is the health monitoring of wind turbine blades. Stress analysis of the blades can be more accurate grasp the site of health monitoring. The use of fiber Bragg grating(FBG) of health monitoring is a very big step forward to improve the accuracy and feasibility of blades health monitoring.This article based on the wind turbine blade aerodynamic design, combined with the classical momentum and blade element theory design the 1.5MW large wind turbine blade aerodynamic shape. The wind turbine blade weight and material requirements is relatively high, so this article selects the high strength glass fiber reinforced composite materials as the wind turbine blade design materials. That not only meets the requirements of the blade structural strength, but also makes the blades of the weight greatly reduced.Stress Analysis of the structure from the blades can understand the whole wind turbine blade stress and strain distribution. This article mianly analyzes the stress and strain of the wind turbine blades in the uniform load and gravity. Change the corresponding parts of the blade laminate to meet the requirements of structural strength according to the stress analysis results. The finite element model modal analysis of the wind turbine blade shows that the wind turbine blade natural frequencies and mode shapes.The main load of the wind turbine blades to withstand the operation is the wind load. Wind loads simulation on the blade is significance. In this paper, the blade will be divided into a number of wind turbine blade airfoil cross-section, using FLUENT software to calculate the cross sections of each airfoil surface pressure under wind load, extract the pressure points on the airfoil cross-section values. The MATLAB fitting the cross section of each airfoil a function of pressure and the coordinates will be written into the function of the APDL program. In the ANSYS software, the carve steps is loaded into the finite element model, and analyzed.In order to verify the validity of theoretical analysis, 300W small wind turbine blades are used for test analysis. The test is based on structural analysis of the blades and layout of the Bragg sensor (FBG) and strain gauges. The grating sensors imbeded into the blade overlay while production, the the strain gauges are pasted on the blade surface after complication. This blade experiment was mainly done on a single point and multiple points of load tests, compare experimental data with theoretical in different facet. The experiments not only verify the theoretical model analysis is correct, but also confirmed the grating sensor health monitoring for wind turbine blade is feasible.