Strain Monitoring on Damaged Composite Laminates Using Digital Image Correlation

Composite laminates are susceptible to impact damage.Nowadays, damage detection mainly depends on visual inspection and C scan. But thesetwo methods are limited to the technical skill of the inspectors, causingmissed detection or even fault detection. The current full field digital image correlation (DIC) technique has been gradually applied to the measurement of the structural surface. This paper devotes to exploring the DIC monitoring technique and the actual surface strain data processing methods. Composite laminateswith different BVID damage degrees are studied under both tensile and compressive loading conditions. It is shown that DIC method is able to capture an obvious strain singularity on damage area of the composite laminate. Strain singularity is caused by fiber crack under tensile loading condition and buckling under compressive loadingcondition. Influencing factors ofthe composite surface monitoring are then discussed.