Damage Identification in Hemp Fiber (Cannabis sativa) Reinforced Composite Plates Using MAC and COMAC Correlation Methods: Experimental Study

Abstract

ABSTRACT The use of hemp fiber has increased in recent decade due to the increasing demand for sustainable, recyclable, and biodegradable materials. Hemp fibers are obtained from the stem of a plant for the reinforcement of composites. In this work, experimental modal analysis was performed on a hemp fiber (Cannabis sativa) reinforced plate with a free-free condition. Preliminary results of modal parameter identification of multiple damage detection are presented. To consider multiple damage effects, an undamaged plate including six damaged scenarios are considered. For each scenario, natural frequencies with mode shape were identified with accuracy using accelerometer sensors and impact hammer. Measured the natural frequencies and mode shape for undamaged and damaged plates are compared with each other. To establish the correlation between undamaged and damaged plate, modal assurance criterion (MAC) are considered. In addition, coordinated multiple modal assurance criterion (COMAC) considered that were highly sensitive to the severity of damage scenarios with sufficient mode consideration. It is clearly observed that a COMAC plot results show more sensitive compared to MAC plot results. It reveals that even small level damage present in the specimen can be easily examined through coordinate modal assurance criterion.