Simultaneous three-dimensional dynamic deformation measurements with pulsed digital holography.

Area of Science:

• Optical Engineering
• Metrology
• Vibration Analysis

Background:

• Accurate measurement of three-dimensional (3-D) deformation is crucial for understanding object dynamics.
• Traditional methods often lack the simultaneous, full-field measurement capabilities required for complex vibrations.

Purpose of the Study:

• To develop and demonstrate a digital holographic method for simultaneous measurement of 3-D object deformation.
• To integrate shape measurement for a comprehensive analysis of vibrating objects.

Main Methods:

• Utilized digital holography with a double-pulse ruby laser and three illumination directions.
• Employed a single CCD image to incoherently add three independent digital holograms.
• Applied the Fourier-transform method for phase evaluation and the two-wavelength contouring method for shape measurement.

Main Results:

• Successfully obtained three phase maps representing deformation along distinct sensitivity vectors.
• Calculated the total 3-D deformation by vector resultant of the phase map data.
• Acquired 3-D shape information of the test object (cylinder).

Conclusions:

• The presented digital holographic approach enables simultaneous and accurate 3-D deformation measurement of vibrating objects.
• The combined deformation and shape analysis provides a complete understanding of object dynamics under transient and harmonic excitation.