Abstract

It was undertaken to apply holographic techniques to characterize the dynamic behavior and structure of an advanced graphite-epoxy composite part and its ancillary mounting geometry. Holograms of the vibrational modes of the structure are used to accurately map the nodes, maxima, minima, and geometry of the induced motion. Holograms of the displacement patterns of mechanical and thermally induced stress in the structure are also used to map the location and extent of nonuniformities, discontinuities, and micro-structural defects in the volume and mounting of the composite material. Holographic data was imaged by a photo-thermoplastic based holocamera system configured for off-axis holograms and coupled to high resolution video capture for subsequent image analysis.

© Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |

  1. H. Fein, "The Application of Holographic Interferometry to the Characterization of the Dynamics of a Complex Bonded Structure," Proc. SPIE, Adhesives Engineering, 1999, 248-253, (1993).
    [CrossRef]
  2. H. Fein, "Holographic Evaluation of the Material and Dynamic Characteristics of Bonded Compliant Structures," Proceedings of International Conference on the Applications of Lasers and Electro-Optics, (ICALEO) Laser Materials Processing 77, 604-610 (1993).
  3. H. Fein, "An Application of Holographic Interferometry to Evaluate the Material Characteristics of Cast Compliant Structures," in Review of Progress in Quantitative Nondestructive Evaluation, Vol. 15, D.O. Thompson and D. E. Chimenti, eds., (Plenum, New York, 1996).
    [CrossRef]
  4. H. Fein, "Holographic Interferometry Applied to the Characterization and Analysis of the Dynamic and Modal Behavior of Complex Circuit Board Structures," Proc. SPIE, Practical Holography VIII 2176, 256-261 (1994).
    [CrossRef]
  5. Howard Fein, "Applied Holographic Interferometry as a Nondestructive Method for the Dynamic and Modal Analysis of an Advanced Graphite Epoxy Composite Structure," in Review of Progress in Quantitative Nondestructive Evaluation, Vol. 16, D.O. Thompson and D.E. Chimenti, eds., (Plenum, New York, 1997).
  6. C. M. Vest, Holographic Interferometry, (Wiley, New York, 1979), p. 227.
  7. C. M. Vest, Holographic Interferometry, (Wiley, New York, 1979), pp. 179-183.
  8. C. M. Vest, Holographic Interferometry, (Wiley, New York, 1979), p. 229.
  9. "Instant Holocamera," (Newport Corp., Fountain Valley, Ca., 1981).
  10. C. M. Vest, Holographic Interferometry, (Wiley, New York, 1979), p. 155, 180.

Other (10)

H. Fein, "The Application of Holographic Interferometry to the Characterization of the Dynamics of a Complex Bonded Structure," Proc. SPIE, Adhesives Engineering, 1999, 248-253, (1993).
[CrossRef]

H. Fein, "Holographic Evaluation of the Material and Dynamic Characteristics of Bonded Compliant Structures," Proceedings of International Conference on the Applications of Lasers and Electro-Optics, (ICALEO) Laser Materials Processing 77, 604-610 (1993).

H. Fein, "An Application of Holographic Interferometry to Evaluate the Material Characteristics of Cast Compliant Structures," in Review of Progress in Quantitative Nondestructive Evaluation, Vol. 15, D.O. Thompson and D. E. Chimenti, eds., (Plenum, New York, 1996).
[CrossRef]

H. Fein, "Holographic Interferometry Applied to the Characterization and Analysis of the Dynamic and Modal Behavior of Complex Circuit Board Structures," Proc. SPIE, Practical Holography VIII 2176, 256-261 (1994).
[CrossRef]

Howard Fein, "Applied Holographic Interferometry as a Nondestructive Method for the Dynamic and Modal Analysis of an Advanced Graphite Epoxy Composite Structure," in Review of Progress in Quantitative Nondestructive Evaluation, Vol. 16, D.O. Thompson and D.E. Chimenti, eds., (Plenum, New York, 1997).

C. M. Vest, Holographic Interferometry, (Wiley, New York, 1979), p. 227.

C. M. Vest, Holographic Interferometry, (Wiley, New York, 1979), pp. 179-183.

C. M. Vest, Holographic Interferometry, (Wiley, New York, 1979), p. 229.

"Instant Holocamera," (Newport Corp., Fountain Valley, Ca., 1981).

C. M. Vest, Holographic Interferometry, (Wiley, New York, 1979), p. 155, 180.

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (10)

Figure 1.
Figure 1.

Off-Axis Holographic Interferometry Configuration

Figure 2.
Figure 2.

Composite structure schematic diagram and photo of the actual assembly in place for holographic imaging. Photographic point of view from this image and all holograms is directly along a line of sight orthogonal to the object center. The structural curve is not apparent from this aspect. Fringe patterns will be superimposed over structure image in following data.

Figure 3.
Figure 3.

The holographic fringe pattern shown here defines the primary bending mode of the structure. The frequency in this case was nominally 56 Hz. It is seen to be a clear displacement phenomenon whose amplitude increases linearly from the mounting clamp assembly of the component.

Figure 4.
Figure 4.

This fringe geometry illustrates strong torsional displacement pattern produced at a nominal frequency of 121 Hz. The nodal ridge dividing the high amplitude fringe groups on the image top and bottom corners denotes that a phase change occurs between them. This defines a high stress point which could result if the inherent noise spectrum of the structure in its operational configuration includes a component at this frequency.

Figure 5.
Figure 5.

First bending/conjugate mode at 545 Hz.

Figure 6.
Figure 6.

Second bending/conjugate mode at 564 Hz.

Figure 7.
Figure 7.

Higher order complex mode is a superposition of a second bending and second torsional mode at 1.61 kHz. The broad nodal area varies smoothly into the sharp nodal lines in both torsional and bending stress showing the location of changes in direction between the high displacement edges and corners.

Figure 8.
Figure 8.

Constraint induced stress gradient.

Figure 9.
Figure 9.

Differential stress loading.

Figure 10.
Figure 10.

Internal structural flaw identified when local thermal stress from a 15 degree C increase in temperature is applied to the back of the composite material. The non-uniform displacement distribution indicates the location and extent of the internal flaw.

Equations (2)

Equations on this page are rendered with MathJax. Learn more.

D = ( 2 )
D = ( ξ n λ 4 π )

Metrics