Diagnostic layer and methods for detecting structural integrity of composite and metallic materials

A diagnostic system for detecting a structural condition of a material, said diagnostic system comprising:

• a diagnostic layer comprising:
• a thin and flexible dielectric substrate having embedded therein:
• a network of actuators/sensors spatially distributed such that at least two actuators/sensors detect a propagating stress wave generated by at least one other actuators/sensors;
• a plurality of conductive elements electrically interconnecting said actuators/sensors;
• and
• an output lead electrically connected to said conductive elements;
• a signal receiving means electrically coupled to said output lead for receiving said output signals from said actuators/sensors;
• and
• an interfacing means in electrical communication with said signal receiving means, said interfacing means comprising a processing means for processing said output signals and generating data representing said structural condition of said material.

A method for detecting a change in a structural condition of a material, said method comprising the steps of:

• a) providing said material a diagnostic layer, said diagnostic layer comprising:
• a thin and flexible dielectric substrate having embedded therein:
• a network of actuators/sensors spatially distributed such that at least two actuators/sensors detect a propagating stress wave generated by at least one other actuators/sensors;
• a plurality of conductive elements electrically interconnecting said actuators/sensors;
• and
• an output lead electrically connected to said conductive elements;
• b) transmitting a first input signal to said at least one other actuators/sensors through said output lead;
• c) receiving a first set of output signals from said at least two actuators/sensors in response to said first input signal;
• d) subsequently transmitting a second input signal to said at least one other actuators/sensors through said output lead;
• e) receiving a second set of output signals from said at least two actuators/sensors in response to said second input signal;
• and
• f) analyzing said first set of output signals and said second set of output signals to determine a difference between said first set of output signals and said second set of output signals, wherein said difference represents said change in said structural condition.

A diagnostic layer for detecting a structural condition of a material, said diagnostic layer comprising:

• a thin and flexible dielectric substrate having embedded therein:
• a network of actuators/sensors spatially distributed on said substrate, said actuators/sensors capable of generating electrical signals representative of a structural condition of said material, wherein at least two actuators/sensors detect a structural condition in a region of said material;
• a plurality of conductive elements electrically interconnecting said actuators/sensors;
• and
• an output lead electrically connected to said conductive elements.