Completion of torsion box demonstrator test program

July 2012

The TAPAS 12 meter span torsion box demonstrator, with a thermoplastic stiffened skin, has been subjected to a certification test campaign. Fokker Aerostructures subcontracted and coordinated this test, carried out by the Dutch Aerospace Laboratories (NLR).

After impact damages, a fatigue program was run. Then, four different static load cases of 165% Limit Load were applied without damage to the composite structure. At high loads, local buckling of the skin between stiffeners was observed. This is meant to be and is part of the post-buckling design philosophy, whereby weight is reduced by allowing local buckling to occur. Next, severe (100 Joule) impacts were applied to locally damage the structure. The product was then again subjected to fatigue loads. No growth of the damages was observed. This can be seen as proof of the toughness of thermoplastic matrices.
Finally, on July 24th, the product will be tested to failure.