Elastic Property Evaluation of Fiberglass and Epoxy Resin Composite Material Using Digital Image Correlation

Area of Science:

• Materials Science
• Mechanical Engineering
• Composite Materials

Background:

• Digital Image Correlation (DIC) is a non-contact optical method for measuring deformation.
• Traditional analog extensometers are widely used for mechanical testing.
• Composite materials offer high strength-to-weight ratios but require precise characterization.

Purpose of the Study:

• Evaluate the sensitivity and limitations of simplified Digital Image Correlation (DIC) equipment.
• Compare DIC measurements with analog extensometer data for fiberglass/epoxy composites.
• Validate experimental results against Classical Laminate Theory (CLT).

Main Methods:

• Fabricated composite plates ([0]3, [90]4, [±45]3) via manual lamination.
• Conducted tensile tests following ASTM D3039 and D3518 standards.
• Employed DIC to capture strain fields and compared with analog extensometer readings.

Main Results:

• DIC showed discrepancies: 11.1% for longitudinal modulus (E1) and 5.6% for transverse modulus (E2).
• DIC exhibited lower efficiency under low deformation due to equipment limitations.
• CLT predicted a longitudinal modulus (Ex) of 7136 MPa for [±45]3 laminate, versus 5208 MPa experimentally (31.2% difference).

Conclusions:

• Simplified DIC equipment has limitations affecting accuracy in composite mechanical testing.
• Analog extensometers remain reliable, but DIC offers potential for non-contact analysis.
• Discrepancies between experimental data and CLT highlight the need for improved composite modeling and DIC techniques.