Curvature mode shape-based damage assessment of carbon/epoxy composite beams

In this article, a combined analytical and experimental damage assessment method using curvature mode shapes is developed. The curvature mode is selected due to its sensitivity to the presence of the damage and the localized nature of the changes. An analytical relationship between the damaged and the healthy beams is formulated, for which the effect of damage in the form of stiffness loss is accounted. This relationship is later used to estimate the extent of damage from the experimentally identified changes in structural dynamic characteristics. Surface-bonded piezoelectric sensors are used to directly acquire the curvature modes of composite structures, which simplify the identification procedure. The specimens are made of carbon/epoxy laminated composite beams. Several different types of damages are introduced in the beams (i.e., delamination, impact, and saw-cut damages) to simulate possible damage scenarios. Several limitations and remarks of the proposed experimental and damage identification approaches are discussed. The study shows that the present technique using curvature mode shapes and piezoelectric materials can be used effectively to locate the damage in the laminated composite structures.