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US 11,781,967 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
A device and method are provided for determining whether a laminate is bonded or debonded from its substrate. The device and method provide simple, accurate, rapid, cost-effective, and reliable means for assessing the bonding state of a laminated substrate.
Claims20
A device for detecting a bonded state or a debonded state between a substrate and a laminate, the device comprising:
- an impulse hammer having 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
A method for determining a bonded state or a debonded state between a substrate and a laminate, the method comprising the steps of:
- impacting a region of the laminate with a pulse hammer for a time period, the force versus time pulse data comprising a plurality of data points spanning fractions of the time period;
- receiving a force versus time pulse data from a pulse hammer having a force sensor;
- normalizing the pulse data to produce a normalized pulse curve;
- and
- calculating a pulse RMSD by comparing the normalized pulse curve to a universal profile;
- whereby, if the pulse RMSD exceeds a profile threshold, the laminate is determined to be in a debonded state, and if the pulse RMSD does not exceed the profile threshold, the laminate is determined to be in a bonded state.
3 more elements
Dependencies are inferred from the claim text.