Finite element method

Structural engineering

Biology

Composite number

Engineering

Fatigue limit

Philosophy

Paleontology

Joint (building)

Composite material

Materials science

Turbine blade

Stress (linguistics)

Flange

Turbine

Linguistics

Subduction

Reinforcement

Tectonics

Delamination (geology)

Mechanical engineering

Applied Composite Materials

This paper presents a study of fatigue performance of composite T-joints used in wind-turbine blades. A T-joint with various fibre reinforcement architectures were selected to investigate its fatigue behaviour. The 3D angle interlock T-joint was found to have the best performance in both static and fatigue loading. Increasing the static properties increases fatigue performance while the increasing rate in life performance is changed with the number of fatigue cycles. A finite element (FE) model was developed that can determine the stress distribution and the initiation and propagation of a delamination crack. The location for through-thickness reinforcement is very important to improve fatigue performance of composite T-joints. Fatigue performance is significantly improved for the web with through-thickness reinforcement while fatigue performance is decreased if the through-thickness reinforcement is applied to the flange-skin regions. The interlaminar veil significantly increases the ultimate strength under static load but fatigue performance at high stress cycles is increased but not significantly.

Fatigue Behaviour of Composite T-Joints in Wind Turbine Blade Applications