Structural health monitoring (SHM) transducer assembly and system

A transducer assembly, comprising:

• a polyimide film;
• a pair of electrically conductive traces bonded to the polyimide film, wherein each of the electrically conductive traces includes a first contact pad and a second contact pad and wherein the polyimide film includes a pair of vias formed therein to expose each of the first contact pads for connection to a structural health monitoring unit;
• a layer of non-conductive adhesive attached to the polyimide film and encapsulating the electrically conductive traces in association with the polyimide film;
• a flat electromechanical transducer, wherein the layer of non-conductive adhesive is adapted to attach the flat electromechanical transducer to the polyimide film such that a signal transmitting face of the flat electromechanical transducer forms a substantially flat surface with the non-conductive adhesive layer to prevent any voids when the transducer assembly is attached to an object for structural health monitoring;
• and
• a pair of electrically conductive adhesive patches to separately connect each of the second contact pads of the electrically conductive traces to the flat electromechanical transducer through the layer of non-conductive adhesive.

A system for structural health monitoring, comprising:

• a structural health monitoring unit;
• a plurality of structural health monitoring transducer assemblies connected to the structural health monitoring unit to send stress waves into an object being monitored and to receive return stress waves from the object for monitoring the structural health of the object, wherein each structural health transducer assembly comprises:
• a polyimide film;
• a pair of electrically conductive traces attached to the polyimide film, wherein each of the electrically conductive traces include a first contact pad and a second contact pad and wherein the polyimide film includes a pair of vias formed therein to expose each of the first contact pads for connection to the structural health monitoring unit;
• a layer of non-conductive adhesive attached to the polyimide film and encapsulating the electrically conductive traces in association with the polyimide film;
• a transducer, wherein the layer of non-conductive adhesive is adapted to attach the flat transducer to the polyimide film such that a signal transmitting face of the transducer forms a substantially flat surface with the non-conductive adhesive layer to prevent any voids when the transducer assembly is attached to an object for structural health monitoring;
• and
• a pair of electrically conductive adhesive patches to separately connect each of the second contact pads of the electrically conductive traces to the transducer through the layer of non-conductive adhesive.

A method for forming a transducer assembly, comprising:

• providing a first layer of dielectric material;
• placing a pair of electrically conductive traces adjacent to the first dielectric layer, wherein each of the electrically conductive traces includes a first contact pad and a second contact pad;
• forming a pair of vias in the first layer of dielectric material to expose each of the first contact pads;
• attaching a second layer of dielectric material to the first layer of dielectric material with the pair of electrically conductive traces disposed between the first and second layers of dielectric material;
• and
• attaching a transducer to an opposite side of the second layer of dielectric material;
• and
• electrically connecting each second pad to the transducer by disposing an electrically conductive patch or electrically conductive paste in each via.

A method for forming a transducer, comprising:

• providing a polyimide film;
• bonding a pair of electrically conductive traces to the polyimide film, wherein each of the electrically conductive traces include a first contact pad and a second contact pad;
• forming a pair of vias in the polyimide film to expose each of the first contact pads for connection to a structural health monitoring unit;
• attaching a layer of non-conductive adhesive to the polyimide layer and encapsulating the electrically conductive traces between the non-conductive adhesive layer and the polyimide film;
• attaching a flat transducer to the polyimide film by the layer of non-conductive adhesive, wherein the layer of non-conductive adhesive is adapted to attach the flat transducer to the polyimide film such that a signal transmitting face of the flat transducer forms a substantially flat surface with the non-conductive adhesive layer to prevent any voids when the transducer assembly is attached to an object for structural health monitoring;
• and
• separately connecting each of the second contact pads of the electrically conductive traces to the flat transducer through the layer of non-conductive adhesive by an electrically conductive adhesive patch.

A method for monitoring structural health, comprising attaching an array of transducer assemblies to an object for monitoring the structural health of the object, each transducer assembly comprising a structure to substantially minimize mechanical impedance mismatch and increase a signal-to-noise ratio during monitoring of the object, the structure comprising:

• a polyimide film;
• a pair of electrically conductive traces bonded to the polyimide film, wherein each of the electrically conductive traces include a first contact pad and a second contact pad and wherein the polyimide film includes a pair of vias formed therein to expose each of the first contact pads for connection to a structural health monitoring unit;
• a layer of non-conductive adhesive attached to the polyimide film and encapsulating the electrically conductive traces in association with the polyimide film;
• a transducer, wherein the layer of non-conductive adhesive is adapted to attach the transducer to the polyimide film such that a signal transmitting face of the transducer forms a substantially flat surface with the non-conductive adhesive layer to prevent any voids when the transducer assembly is attached to an object for structural health monitoring;
• and
• a pair of electrically conductive adhesive patches to separately connect each of the second contact pads of the electrically conductive traces to the transducer through the layer of non-conductive adhesive;
• and
• utilizing the array of transducer assemblies to monitor the structural health of the object.