Value range optimization of ply parameter for composite wind turbine blades based on sensitivity analysis

Blade ply parameters are important design factors that influence the performances of wind turbine blades. This paper proposes a sensitivity analysis method of the blade ply parameters that fuses the relative sensitivity analysis of multi-parameters and the interval sensitivity analysis of single-parameters. A method for identifying the stability region of the sensitive parameters is presented. Coupled mathematical models of the blade static strength and the blade stiffness as a function of the blade ply parameters are established by incorporating experimental design, finite element analysis, and multiple nonlinear regression. The moment independent sensitivity analysis method based on the cumulative distribution function is used to analyze the multi-parameter relative sensitivity, and the direct derivative method was used to analyze single-parameter interval sensitivity. The sensitive and insensitive ply parameters are identified, and the initial stability and instability regions of the ply parameters are determined. A case study of a 1.5 MW blade shows that the ply angle and the ply thickness are sensitive parameters, and the ply stacking sequence is an insensitive parameter. The optimal and stability value ranges of the ply angle and the +/- x degrees ply thickness ratio are [44 degrees, 45 degrees] and [44 %, 48 %], respectively. Hence, the validity and reliability of the proposed method is verified.