Application of Digital Image Correlation to Measurement of Packaging Material Mechanical Properties

Among various packaging materials, papers and polymer plastics are the most common due to their light weights, low costs, and other advantages. However, their mechanical properties are difficult to measure precisely because of their softness. To overcome the difficulty, a new measure instrument prototype is proposed based on an optical method known as the digital image correlation (DIC). Experiments are designed to apply the DIC to measure mechanical properties of flexible packaging materials, including the stress-strain relationship, the Poisson ratio, the coefficient of heat expansion, the creep deformation, and the top-pressure deformation of corrugated box. In addition, the low frequency vibration of package is simulated, and the vibration frequencies are measured by DIC. Results obtained in the experiments illustrate the advantages of the DIC over traditional methods: noncontact, no reinforced effect, high precision over entire area, wide measurement range, and good measurement stability.