Fig 13. 
  
  
A typical fringe pattern observed Fig 14. 
during reconstruction of a double- : 
exposure hologram recording the 
airfoil No. 2 acted upon by a radial 
(tensile) load applied at tip of 
the blade 
30 
  
A typical fringe pattern observed 
during reconstruction of a double- 
exposure hologram recording the 
airfoil No. 2 acted upon by a tor- 
sional load applied at tip of 
the blade