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: