Dynamic loading on a wind turbine blade and resin bridges

Analysis of a wind turbine blade

The test pan­el was an orig­i­nal sec­tion of a wind tur­bine blade with a defect (a foam block with bridges). Pre­vi­ous­ly the defect was locat­ed by infil­tra­tion of col­or through small drilled holes. The sam­ple is exam­ined non-destruc­tive­ly by the SE-Sen­sor.

 

 

left: Set-up

right: Time aver­age result at fre­quen­cy of 2569Hz show­ing the debond­ing area.

 

 

 

 

left: Live view of sur­face includ­ing shearing.

right: Time aver­age mea­sure­ment from the marked area in the live image.

 

 

 

De-bonding of resin bridges

A GFRP sand­wich with foam blocks and resin bridges should be exam­ined. The detec­tion of the defect type und struc­ture is very quick and reli­able in this case, because the defects are vis­i­ble, not only at their local nat­ur­al fre­quen­cies, but also due to their forced deflec­tion shapes over a wide fre­quen­cy bandwidth.

 

The exci­ta­tion fre­quen­cies of the select­ed mea­sure­ments are 1398 Hz (1), 3133 Hz (2), 2442 Hz (3) and 4906 Hz (4) — num­ber­ing in fol­low­ing images: