Sharif Journal of Mechanical Engineering

Sharif Journal of Mechanical Engineering

Modal-based Structural Health Monitoring of a Composite Wind-Turbine Blade

Document Type : Article

Authors
Seyed Mohammad Hosein Sharifi
Gholamreza Rashed
MohammadFoad Salamizadeh
Department of Mechanical Engineering, Petroleum University of Technology, Abadan Faculty of Petroleum, Abadan.
10.24200/j40.2025.67449.1745
Abstract
Health monitoring of rotating machinery, particularly wind turbines, has become increasingly important due to the demand for reliability, efficiency, and reduced maintenance costs in renewable energy systems. Wind turbine blades, being large composite structures subjected to dynamic loading and harsh environmental conditions, are highly vulnerable to damage such as crack initiation and growth. Early detection of such damage is critical to prevent catastrophic failures and costly downtime. This study applies vibration-based modal analysis in combination with fracture mechanics principles to monitor the health of a composite wind turbine blade. A finite element (FE) model was developed in ANSYS to simulate the structural response of the blade under different crack lengths and positions. The natural frequencies and mode shapes were extracted for both healthy and defective blades. Results reveal a clear relationship between crack growth and frequency reduction. Critical crack depths were identified: 250 mm for cracks near the root, 300 mm for cracks in the middle, and 350 mm for cracks near the tip. Furthermore, each mode exhibited different levels of sensitivity to crack location, with bending modes more responsive near the root and torsional modes more affected near the tip. These findings highlight the potential of modal analysis as a practical tool for structural health monitoring (SHM) of wind turbine blades in real-time applications.
Keywords
Structural health monitoring
wind turbine blade
crack growth
finite element method
modal analysis
Subjects
 
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