NDT on Wind Rotor Blades

First test NDT Mea­sure­ment by shearog­ra­phy on a wind tur­bine blade in 1996 by P. Mäck­el, L. Yang, G. Kupfer and A. Tiemich at Kas­sel Uni­ver­si­ty. The object is a spe­cial wind rotor blade of a sin­gle wing wind tur­bine ener­gy plant.


Applied load­ing method: Load­ing by inter­nal pres­sure (the blade has been sealed). A man­u­al pump has been used to increase a pres­sure dif­fer­ence against the sur­round­ing. The fringe images show areas at dif­fer­ent loca­tions. The fringes are pro­por­tion­al to the out of plane defor­ma­tion gra­di­ents of the sur­face, which allows to iden­ti­fy inho­mo­ge­neous stiff­ness of the struc­ture: left — Delam­i­na­tion; right — Axi­al crack; cen­ter ‑Struc­tur­al change over (dif­fer­ent num­ber of glas­fiber layers).