Material damage system and method for determining same
AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorRobert S. Okojie
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Abstract
A system and method for determining a change in a thickness and temperature of a surface of a material are disclosed herein. The system and the method are usable in a thermal protection system of a space vehicle, such as an aeroshell of a space vehicle. The system and method may incorporate micro electric sensors arranged in a ladder network and capacitor strip sensors. Corrosion or ablation causes a change in an electrical property of the sensors. An amount of or rate of the corrosion or the ablation and a temperature of the material is determined based on the change of the electrical property of the sensors.
Claims18
A system comprising:
- a material susceptible to corrosion or ablation and having a thickness defined between a first end and a second end;
- a first sensor and a second sensor on the material and extending along the thickness adjacent the first end and toward the second end, wherein the first and second sensors extend parallel to one another and are both configured to change in length in response to corrosion or ablation of the susceptible material, wherein a first electrical property of the first sensor is dependent on a length of the first sensor, wherein a second electrical property of the second sensor is dependent on a length of the second sensor, wherein the first electrical property has a different dependency on a temperature of the material than the second electrical property;
- an electrical circuit coupled to the first sensor and the second sensor to determine changes in the first and second electrical properties;
- and
- a processor configured to estimate the temperature and thickness based on the changes in the first and second electrical properties.
A system comprising:
- a material comprising a first surface and a second surface;
- a first grouping of sensors embedded in the material, the first grouping of sensors comprising:
- a first ladder sensor comprising a first plurality of electrical components extending between the first surface and the second surface, the first ladder sensor having a first electrical property that varies in response to a change in a thickness of the material at a first location and variations in a temperature of the material;
- a second ladder sensor comprising a second plurality of electrical components extending between the first surface and the second surface, the second ladder sensor having a second electrical property that varies in response to a change in the thickness at a second location;
- and
- a capacitive strip sensor extending between the first surface and the second surface, the capacitive strip sensor having a capacitance that varies in response to a change in the thickness at a third location, wherein the first ladder sensor, the second ladder sensor, and the capacitive strip sensor extend parallel to one another;
- and
- a processor communicably coupled to the grouping of sensors, wherein the processor is configured to:
- estimate the thickness of the material at the first, second, and third locations based on sensor signals generated via the first ladder sensor, the second ladder sensor, and the capacitive strip sensor, respectively;
- and
- estimate the temperature of the material based on the sensor signal generated via the first ladder sensor.
Dependencies are inferred from the claim text.