Simulation‐based time‐dependent reliability analysis for composite hydrokinetic turbine blades

The reliability of blades is vital to the system reliability of a hydrokinetic turbine. A time‐dependent reliability analysis methodology is developed for river‐based composite hydrokinetic turbine blades. Coupled with the blade element momentum theory, finite element analysis is used to establish the responses (limit‐state functions) for the failure indicator of the Tsai–Hill failure criterion and blade deflections. The stochastic polynomial chaos expansion method is adopted to approximate the limit‐state functions. The uncertainties considered include those in river flow velocity and composite material properties. The probabilities of failure for the two failure modes are calculated by means of time‐dependent reliability analysis with joint upcrossing rates. A design example for the Missouri river is studied, and the probabilities of failure are obtained for a given period of operation time.