Multi-objective optimization and modeling of a natural fiber hybrid reinforced composite (P_xG_yE^z) for wind turbine blade development using grey relational analysis and regression analysis

Due to the increasing demand for clean and sustainable energy, wind turbine technology has also witnessed significant developments in terms of its output capacity which is proportional to its size (length of wind turbine blades). The only limitation to this scaling is the availability of applicable materials with expected strength and low weight which can support a longer span wind turbine blade. Although studies have been carried out on alternate materials for the development of wind turbine blades, the use of Grey Relational Analysis for the optimization of natural fiber-reinforced composites for this application is rare. Also, pineapple leaf fiber, having considerable mechanical properties and low density has not been optimally considered as reinforcement in this regard. This is a robust study concerned with developing more eco-friendly materials for application in the manufacture of wind turbine blades. In this study, a material PxGyEz, a natural fiber/synthetic fiber polymer composite was developed and optimized based on the major criteria for selecting materials for wind turbine blades which are high tensile strength, high flexural strength, and low density. Grey relational analysis coupled with the Taguchi robust optimization technique was used for the optimization process and statistical analysis was employed to know the percentage contribution of each of the variable parameters (PALF volume percentage, glass fiber volume percentage, and fiber length) to the grey relational grades. The material P10G20E15 was the optimum having a grey relational grade of 0.7977 at experimentation and tensile strength of 95.3144 MPa, a flexural strength of 92.818 MPa, and a density of 1.3274 g/cm3. SEM analysis showed microstructural formations that explained the mechanical and physical behavior of the optimized hybrid composite. Simulation of an NREL 5 MW wind turbine blade developed with the optimized material P10G20E15 proved reliable for service with a 64% reduction in weight.