Damage identification for a beam structure based on a PVDF piezoelectric film combined sensor

Abstract

The structural strain curvature mode is widely used in structural health monitoring because of its high sensitivity to local changes and accurate damage localization capability. In this research, a combined polyvinylidene fluoride (PVDF) sensor was designed and manufactured based on measurement characteristics of the PVDF sensor. The designed sensor can directly measure the response signal of the strain difference in the structure. According to the central difference principle, the measured value is deduced and used to obtain the local strain curvature of the structure, and the strain curvature modal parameters of the structure are identified with the operating modal identification method. Taking the strain curvature mode shape difference as the damage index, the damage recognition results of the single-chip PVDF sensor and the combined PVDF sensor are compared by performing single damage, multiple damage and damage range experiments on a beam structure. The experimental results show that the combined PVDF sensor proposed in this study is more sensitive to local minor damage.