Damage detection in composite structure based on damage recognition an localization algorithm of high accuracy

Composite laminates are widely used due to the advantages of low density, high specific modulus and specific strength, strong internal damping and excellent chemical stability. Invisible damage by impact and fatigue such as matrix crack, internal delamination and fiber break may lead to sharp decline of structural strength and stability and finally makes composite structural failure. This paper proposes a damage index weighted average localization algorithm (DIA), which can realize a quick damage identification and damage localization of high accuracy. The proposed algorithm does not require damage imaging, and thus has the potential of realizing Structural Health Monitoring on line and in situ. Pre-experiments of real impact damages and artificial bonded bolt are done on composite laminates of small sizes. At last, to reduce experiment cost, the bolts are bonded on laminates to replace real impact damage for validation of DIA. Damage identification is successfully realized with damage localization error lower than 5 mm. A regular PZT arrangement with fewer sensors verifies that 6 sensors are enough for localization error of 20 mm and a random PZT arrangement with one or two sensors missing from the initial sensor array will not influence the localization accuracy.