Experimental validation of the applicability of effective spring boundary conditions for modelling damaged interfaces in laminate structures

• Published in: Composite structures 2021-10, Vol.273, p.114141, Article 114141
• Main Authors: Golub, Mikhail V., Doroshenko, Olga V., Wilde, Maria V., Eremin, Artem A.
• Format: Article
• Language: English
• Subjects: Damaged interface; Experiment; Guided waves; Identification; Laminate structure
• ISSN: 0263-8223; 1879-1085
• DOI: 10.1016/j.compstruct.2021.114141

The paper presents the experimental validation of the applicability of the effective spring boundary conditions (ESBC), where spring stiffness is expressed in terms of material properties and damage characteristics, for modelling the dynamic behaviour of laminates with damaged interfaces. For this purpose, several intact and defected multi-layered samples manufactured from aluminium plates adhesively bonded with two-sided epoxy tape have been considered. To simulate imperfect interfaces, either a particular surface of one of the adherents or of the adhesive has been mechanically damaged with varying severity before the bonding. Elastodynamic motion excited in the samples by thin surface-mounted piezoelectric transducers has been acquired with laser Doppler vibrometer in the form of B-scans of the specimen’s top surface. The wavenumber-frequency analysis of the measured data is performed to extract information on dispersion curves of guided waves propagating in the investigated laminates. It is demonstrated that changes in the properties of guided waves caused due to damaged interfaces are adequately described by the ESBC, and spring stiffness expressed via material and damage characteristics in ESBC allows to characterize properly the severity of the interface degradation in multi-layered structures.