Method for measurement of composite heat damage with infrared spectroscopy
AssigneeThe Boeing Company
InventorsPaul H. Shelley, Jeffrey R. Kollgaard, Diane R. LaRiviere
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Abstract
A non-destructive method determines an amount of heat exposure to a resin-fiber composite substrate. A value of infrared energy reflected by a composite substrate is determined. The value of infrared energy reflected, or conversely absorbed, is correlated to a degree or amount of heat exposure. According to an aspect of the present invention, one method utilizes an infrared spectrometer to determine infrared absorbance of a composite substrate. The infrared energy of the reflected beam is then compared with the pre-determined value of infrared energy reflected off a reference heat damaged composite substrate to determine the amount of heat exposure.
Claims55
A non-destructive method for determining an amount of heat exposure to a resin-fiber composite substrate, the method comprising:
- non-destructively determining a value Is of infrared energy reflected by a surface on the composite substrate;
- and
- correlating the value Is of the infrared energy reflected to an amount of heat exposure, wherein determining Is includes determining absorbance at at least one wavenumber wherein increased infrared absorbance reflects exposure by the composite substrate to heat greater than 300 degrees F.
A non-destructive method for determining an amount of heat damage to a resin-fiber composite sample, the method comprising:
- transmitting an infrared beam onto a sample of a resin-fiber composite, wherein transmitting an infrared beam includes transmitting the infrared beam in a direction approximately in alignment with fibers in the sample:
- detecting a reflected infrared beam reflected by the sample;
- determining infrared absorbance of the sample;
- and
- correlating the infrared absorbance to an amount of heat damage to the sample, wherein correlating the infrared absorbance includes determining absorbance at at least one wavenumber wherein increased absorbanee reflects exposure by the composite sample to heat greater than 300 degrees F.
A non-destructive method for determining an amount of heat exposure of a resin-fiber composite sample, the method comprising:
- transmitting an infrared beam onto a sample of resin-fiber composite;
- detecting a reflected infrared beam reflected by the sample;
- determining a first infrared absorbance of the sample from the reflected infrared beam at a first wavenumber, wherein the first wavenumber corresponds with an infrared spectra of a heat damaged composite surface;
- determining a second infrared absorbance of the sample from the reflected infrared beam at a second wavenumber, and the second wavenumber corresponds with an infrared spectra of a heat damaged composite surface;
- deriving a first difference between the first infrared absorbance and the second infrared absorbance;
- and
- quantitatively determining an amount of heat exposure by correlating the first difference to a plurality of reference samples exposed to various amounts of heat.
A non-destructive method for determining a degree of heat exposure of a resin-fiber composite substrate, the method comprising:
- determining an alignment direction of fibers in the substrate;
- transmitting an infrared beam onto the substrate in alignment with the alignment direction;
- filtering with a first filter a reflected infrared beam reflected by the substrate;
- detecting a first filtered portion of the reflected infrared beam;
- determining a first infrared absorbance of the substrate;
- and
- correlating the first infrared absorbance to a degree of heat exposure by comparison to a plurality of reference samples exposed to various amounts of heat, including at least one reference sample exposed to temperatures over 300 degrees F.
Dependencies are inferred from the claim text.