A Numerical Study for Damage Detection of a Thin Plate Using Pseudo Local Flexibility Method with Rotary Measurement

Abstract

Plate structures are widely used as important structural components in many engineering applications, hence structural condition assessment of in-service plate structures plays an important aspect of global structural health monitoring. Recently, vibration-based structural damage detection techniques that perform damage diagnosis of a structure based on its structural dynamic characteristic parameters attracted great attention in the research community. Hsu et al. (2014) developed the Pseudo Local Flexibility Method (PLFM) which successfully detected damage of hyperstatic beam structures using fewer modes. The PLFM releases the restriction that the virtual forces can only induce stresses in a local part of the structure for the LFM. In this way, the non-local virtual forces that cause concentrated stresses in a local part and relatively small stresses in the other parts of a structure can be employed. Most important, the release of the restriction of the virtual forces makes the virtual forces possible to be found for the plate structures. In this paper, the theoretical basis of the PLFM that uses non-local virtual forces for the plate structures is derived. The effects of the number of modes, the effects of the location of damage, the effects of multiple damage locations, and the effects of noise in modal parameters on the damage detection results of numerical plates are studied. The results show that the proposed PLFM has demonstrated the ability for damage detection, localization and quantification of the plate structures. doi: 10.12783/SHM2015/68