Early detection of impact fatigue damage in an adhesively-bonded connection using acoustic emission

Wind turbine blades carry the risk of impact damage during transportation, installation, and operation. Such impacts can cause levels of damage that can propagate throughout the structure compromising performance and safety. In this study, the effect of impact damage on fatigue damage propagation in test specimens representative of a spar cap...

Fracture and Failure of Adhesives

This article presents an overview of methods for analyzing the facture and failure of adhesives. Special attention is given to stress analysis in adhesive bonds, as the difficulty of performing an accurate stress analysis is a major limitation of many failure analysis methods. The article also covers the effect of manufacturing and...

New indicator for damage localization in a thick adhesive joint of a composite material used in a wind turbine blade

In this paper, a new indicator to localize fatigue damage in a fibre glass composite structure, i.e. spar cap to shear web thick adhesive joint of a wind turbine blade, is presented. This indicator is based on the effect of damping on the phase of the mode shapes of the structure. When fatigue damage occurs, damping increases in the defective...

The effect of the fatigue damage accumulation process on the damping and stiffness properties of adhesively bonded composite structures

Wind turbine blade spar cap to shear web adhesively bonded connections can suffer from damage at the bond-line which can propagate through the structure compromising blade integrity. This study investigates changes in the stiffness and damping of a thick adhesive joint test specimen during a fatigue test. The stiffness is calculated using an...

Using acoustic emission to understand fatigue crack growth within a single load cycle

Current methods for prediction of fatigue crack growth are based on empirical correlations which do not take the crack growth behaviour within a single cycle into account. To improve these prediction methods, more understanding of the physical mechanisms of crack growth is required. In this research the acoustic emission technique was used to...

Characterisation of Fatigue Crack Growth in Adhesive Bonds