A Study of a Noncontact Identification Method of Debonding Damage in External Thermal Insulation Composite Systems Based on Nonlinear Vibration

Due to the influence of materials, construction quality, environmental conditions, and artificial factors, debonding damage in external thermal insulation composite systems (ETICS) has become a common issue in the construction field. A reliable and efficient method for identifying the debonding is still lacking. In this study, four groups of external insulation specimens with different degrees of debonding were fabricated. A non-contact detection method based on nonlinear vibration characteristics was employed, using a laser Doppler vibrometer to acquire the vibration response signals of the specimens. The results demonstrate that this technique can effectively distinguish specimens with different levels of debonding and accurately identify and locate the damage. Moreover, the relative position of the signal acquisition point with respect to the debonding area has no significant impact on the detection results.