Multiplication sampling moire method for full-field deformation measurement of composite materials

Area of Science:

• Materials Science and Engineering
• Mechanical Engineering
• Optical Metrology

Background:

• Conventional moire methods for deformation measurement can suffer from phase measurement errors, especially in the presence of local noise.
• Extracting the fundamental frequency in traditional techniques makes them susceptible to low-frequency background noise interference.
• Robust deformation analysis is critical for evaluating the performance and integrity of composite materials like CFRP.

Purpose of the Study:

• To introduce and validate a Multiplication Sampling Moire (MSM) method for accurate deformation distribution measurement.
• To demonstrate the enhanced noise immunity of the MSM method compared to conventional techniques.
• To assess the applicability of MSM for measuring displacement and strain in composite materials under tensile load.

Main Methods:

• Phase analysis of the second harmonic (second-order frequency) of a single grating pattern was employed.
• The MSM method leverages the spectral separation of the second harmonic from low-frequency noise.
• Experimental grid images of a carbon fiber-reinforced plastic (CFRP) specimen were analyzed.

Main Results:

• The MSM method exhibited strong noise immunity, effectively mitigating phase measurement errors caused by local noise.
• Accurate measurement of displacement and strain distributions was achieved for a CFRP specimen during a tensile test.
• The second harmonic analysis proved superior to fundamental frequency extraction in noisy conditions.

Conclusions:

• The Multiplication Sampling Moire (MSM) method provides a robust solution for deformation measurement in challenging environments.
• MSM effectively overcomes limitations of conventional moire techniques, particularly in scenarios with severe local noise.
• This technique is well-suited for precise deformation analysis of various composite materials.