Open AccessCharacterisation of fatigue damage in a thick adhesive joint based on changes in material damping
Author(s) -
S. Khoshmanesh,
Simon Watson,
Dimitrios Zarouchas
Publication year - 2020
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1618/2/022058
Subject(s) - materials science , structural engineering , adhesive , stiffness , composite material , joint (building) , shear (geology) , damping ratio , layer (electronics) , vibration , engineering , acoustics , physics
The adhesively-bonded connections in a wind turbine blade, e.g. the spar cap to shear web joins, are key elements for the structural integrity of the blade. These joins can suffer from damage at the bond-line which can propagate through the structure and compromise the operation of the blade. In this paper, we determine the damping properties of a test specimen representative of that joining a spar cap and a shear web during a period of progressive damage. In addition to the experimental damping measurement, an analytical dynamic model based on the visco-elastic properties of the material is developed to relate the damping to the loss factor. The experimental results show that when a crack is initiated in the test specimen, the damping increases by around 5-7%. This value increases with the propagation of transverse cracks in the adhesive and reaches a value of 35% when the adhesive layer experiences crack saturation and the damping reaches 45 % before failure occurs. Although a significant change in the damping is observed, there is no significant change in the natural frequency (<1%) and by association little change in the stiffness of the test specimen.