Sunday, 4 March 2012
Damage class four incident (see also rotor blade damage classes)
Rotor blade maintenance and repair standards are to be correlated to structual blade condition and for repair decisions on basis of damage classes. This posting shows without any doubt a damage class four finding (total loss).
In this case there is hypothesis for fatal blade failure mode by carbon UD-girder fiber damage due to transverse force stress induced by glass fiber helix winding technique in order to fix the UD-stack in semi-automated beam production process. This issue is discussed in preparation of next Technical Advisory Board Meeting of the AK R (a committee of the German Wind Association, see also www.akrotor.blogspot.com)
Less severe damages like cracks or delaminations have virtually two dimensions. The first dimension visible at a first glance is what we call inspection findings. The second and comprehensive dimension of a damage can be assessed after removing layer by layer of affected material. It is the difference about damage amount and it's range.