We investigate the mechanics of crack propagation in architected adhesive joints whose adherends are inspired to the base plate of the barnacle Amphibalanus (=Balanus) amphitrite, and feature an array of buried hollow cylindrical channels located perpendicularly to the direction of crack growth. Selective laser sintering is used to obtain the adherends that are subsequently bonded in the double cantilever beam configuration to ascertain the mechanics of crack growth. Finite element (FE) simulations are deployed to determine the strain energy release rate (ERR) and to elucidate the salient features of the fracture process. It is shown that the channels induce a modulation of the ERR and enable a crack tip shielding mechanism. Besides, FE simulations based on a cohesive zone approach indicate the occurrence of crack pinning/depinning cycles that are validated via experiments. A highlight of the present study is the use of a mechanoluminescent (ML) coating to unravel the evolution of the transient stress field in the crack tip region. The coating comprises an optical epoxy resin loaded with doped strontium aluminate phosphors (SrAl2O4/Eu2+) and converts mechanical energy into light emission with intensity proportional to the magnitude of mechanical stress. By combining the ML emission patterns with the stress distribution obtained from FEA, we unveil interesting details of snap-through cracking in architected bio-inspired adhesive joints.
Bibliographical noteKAUST Repository Item: Exported on 2023-09-05
Acknowledgements: The financial support received from of the Natural Sciences and Engineering Research Council of Canada is gratefully acknowledged (NSERC-RGPIN-2021-02446). C.M. acknowledges resources and support from the @STAR and the MaTeRiA laboratories, funded by “Progetto STAR 2─PIR01-00008”- Ministry of University and Research at University of Calabria. N.T. acknowledges support from the Research and Development Program for Promoting Innovative Clean Energy Technologies through International Collaboration (JPNP20005) commissioned by the New Energy and Industrial Technology Development Organization (NEDO). The authors wish to thank Dr. Arturo Pascuzzo for the useful discussions on the FE determination of the ERR. a
ASJC Scopus subject areas
- Materials Science(all)