MEMS based Kelvin probe for material state characterization
AssigneeThe Boeing Company
InventorsRobert B. Greegor, Richard H. Bossi
Life of this patent
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Abstract
A device and method for monitoring the material health of a structure, providing a miniaturized MEMS Kelvin probe within a housing, wherein the Kelvin probe comprises a conductive plate formed of a stable metal and positioned substantially parallel to the structure; a piezoelectric vibrator for vibrating the conductive plate; and an electrical circuit connected to the conductive plate and the structure, wherein the conductive plate and the structure form a capacitor. The device is contained in one small, lightweight package that can be placed at one or more locations of interest. The sensor can be left in-place for continuous monitoring or for active testing at desired intervals, or be brought to the aircraft at desired intervals.
Claims16
A device for monitoring the material health of a structure, comprising a miniaturized MEMS Kelvin probe within a housing, wherein the Kelvin probe comprises:
- a conductive plate disposed entirely within the housing and formed of a stable metal and positioned substantially parallel to the structure, wherein the structure is outside the housing;
- a piezoelectric vibrator coupled to the conductive plate for vibrating the conductive plate relative to the structure, wherein the piezoelectric vibrator comprises edges and the conductive plate does not extend beyond the edges of the piezoelectric vibrator;
- and
- an electrical circuit connected to the conductive plate and the structure, wherein the conductive plate and the structure form a capacitor.
A method for monitoring the structural health of a structural component, using a miniaturized MEMS Kelvin probe, the method comprising:
- attaching the Kelvin probe on the surface of the structural component, wherein the Kelvin probe comprises:
- a conductive plate disposed entirely within a housing and formed of a stable metal and positioned substantially parallel to the structure, wherein the structural component is outside the housing;
- a piezoelectric vibrator coupled to the conductive plate for vibrating the conductive plate relative to the structure, wherein the piezoelectric vibrator comprises edges and the conductive plate does not extend beyond the edges of the piezoelectric vibrator;
- and
- an electrical circuit connected to the conductive plate and the structure, wherein the conductive plate and the structure form a capacitor;
- monitoring a work function of the structural component with the Kelvin probe;
- and
- generating an alarm when the work function of the structural component reaches or exceeds a pre-determined value.
Dependencies are inferred from the claim text.