A summary of the fatigue properties of wind turbine materials

Abstract

Modern wind turbines are fatigue critical machines that are typically used to produce electrical power from the wind. The materials used to construct these machines are subjt%ted to a unique loading spectrum that contains several orders of magnitude more cycles than other fatigue critical structures, e.g., an airplane. To ticiMate fatigue designs, a large database of material properties has been generated over the past several years that is speciaiiied to materials typically used in wind turbines. In this paper, I review these fatigue data. Major sections are devoted to the properties developed for wood, metals (primarily aluminum) and fiberglass. Special emphasis is placed on the fiberglass discussion because this material is current the material of choice for wind turbiie blades. The paper focuses on the data developed in the U. S., but cites European references that provide important insights.

Design, manufacture and testing of small wind turbine blades

“…Timber-laminate composites have long been used in large blades, see e.g Sutherland (2000), but now have been replaced by glass fi bre and carbonfi bre composites. Furthermore for larger blades, the weight of solid timber exceeds that of well-designed laminate.…”

A wind farm controller for load and power optimization in a farm

“…and C T (., .) are implemented into the bending moment equations (8) and (11). In the sequel we approximate the bending moment equations with two linear affine functions.…”

“…Thus, wind farm controllers should employ proper strategies to reduce the extreme fatigue loads. There are many control methods that address fatigue load reduction in single turbines [9], [10], [11], [12], but results on fatigue load control on farm level are lacking.…”

Modelling the effect of temperature on the probabilistic stress–life fatigue diagram of glass fibre–polymer composites loaded in tension along the fibre direction

“…However, even though it is documented that the best fit power-law seldom converges to S u (see e.g. Sutherland [8]), the assumption that it does is used in determining one of the parameters. This results in evident bias in many of the resulting predictions.…”