A composite material has a laminated structure of fiber-reinforced resin layers
and films of a shape-memory alloy. A predetermined strain has been applied to each
film. A damage sensor has a film of an alloy of nickel and titanium. An electric
circuit is bonded to the film, and strain gages are connected to the electric circuit.
The damage sensor can be laminated to the resin layers in place of the film of
the shape-memory alloy. Damage to the composite material is suppressed as follows:
A current is applied to the films of the shape-memory alloy, to monitor change
in electric resistance of the films. The damage is located in response to the change
in electric resistance. Another current is applied to a film of the shape-memory
alloy for which the change is larger than the other films to generate heat for
deforming the film to generate shrinking stress or shear stress to the damage.
