Modal Analysis of aSmall H-Darrieus Wind Turbine Based on 3D CAD, FEA

Abstract:

Rotary machines have many rotating structures necessity design-optimization. Their structure motions are controlled at low-frequency by rigidity, at high-frequency by inertia and at resonance level by damping. Using a modal model, dynamic design of the structure developed can be predicted, analyzed and improved. Recently, H-Darrieus wind turbine (HDWT) has received considerable attention due to its inherent structural characteristics. This machine intends a promising design of a renewable energy conversion system in urban and isolated areas. Though, the system suffers from several dynamic problems caused by geometry, centrifugal and aerodynamic cyclic loadings. Present paper investigated dynamic design-optimization of a three-bladed (HDWT) based on its natural structural parameters using 3D-CAD-FEA using SolidWorks modeling and simulation software. From simulation results obtained, (i) the minimum static safety factor of the wind turbine materials is equal to 1.4. It is greater than that recommended by the international standard IEC 61400-1, assessing an acceptable value to 1.35 when the mass of the system is not obtain by weighting; (ii) the first three natural frequencies of the system are (17.73,

17.99 and 21.07Hz), the resultant mass participates (10.55, 10.44 and 0.04%), the modal damping (9.19, 9.17 and 9.05%), also resonant amplification (5.44, 5.44 and 5.52), magnitude ratios (100, 97.13 and 70.82%)are calculated and mode shapes associated are predicted and analyzed; and (iii) critical operating conditions of wind turbine under forced excitations due to the wind speeds at various regimes are also treated and assessed. The static and dynamic stability and reliability of the system are

shown since all quality indicators tested are consistent according to structure dynamics standards made in steel materials.

Keywords: H-Darrieus wind turbine, Structuredynamics, Design-optimization, Static-analysis, Modal-analysis, 3D-CAD-FEA.