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US 12,674,743 B1Granted
Hammer activated measurement system for testing and evaluating rubber and other materials
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorsJames McDonnell, Lisa Weiser, Jaime Santiago, Colin Ratcliffe
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Abstract
Devices and methods are provided for determining whether a laminate structure is in a bonded or debonded state. The devices and methods provide simple, accurate, rapid, cost-effective, and reliable means for assessing the bonding state of such laminated structures.
Claims20
A device for detecting a bonded state or a debonded state between layers of a laminate structure, the device comprising:
- an impulse hammer comprising a hammer head comprising a force sensor;
- and
- a computer having programmed therein a universal profile and a profile threshold;
- wherein, when the impulse hammer impacts a region of the laminate for a time period, the force sensor delivers force versus time pulse data to the computer, the force versus time pulse data comprising a plurality of data points spanning fractions of the time period;
- the computer normalizes the pulse data to yield a normalized pulse curve, compares the normalized pulse curve to the universal profile, and calculates a root mean square difference (RMSD) between the normalized pulse curve and the universal profile;
- and
- if the RMSD exceeds the profile threshold, the computer provides a notification that the laminate is in a debonded state.
4 more elements
Dependencies are inferred from the claim text.