Life prediction of composite turbine blades under random ocean current and velocity shear

Design, analysis and life prediction of a composite ocean current turbine (OCT) blade has been investigated. Loading on a turbine blade under Gulf Stream in South Florida location (26° 4.3N 79° 55W) at 50 meter depth is considered. Ocean current is random in nature and it varies with respect to time. This variation further intensifies if turbulence is added. In addition, change in velocity profile with ocean depth also introduces shear. During its service life, an ocean current turbine blade would experience repeated and alternating stresses leading to fatigue loading. Sources of such fatigue loading could be many but most dominant ones are due to randomness of ocean current and velocity shear. Effects of these two types of loading are probed and a methodology to predict fatigue life is described in this paper.