Multi step structural health monitoring approaches in debonding assessment in a sandwich honeycomb composite structure using ultrasonic guided waves

•Multiple debonding inside a sandwich composite structure was studied.•Methods to quickly evaluate damages were presented using a damage index matrix map approach which identifies the damage areas (sectors).•Multiple experimental and numerical damage cases were successfully localized using angular and circular sector-based elliptical wave processing (EWP) code.•The code helped to localize multiple debonding and artificial masses present inside, outside, a combination of inside and outside the sensor network.•Nondestructive testing methods were used in the verification of the debonding.