Localization and coalescence of imperfect planar FCC truss lattice metamaterials under multiaxial loadings

Bhuwal, A. S.; Liu, T.; Ashcroft, I.; Sun, W.

Abstract

This study investigates the effect of stress triaxiality on the failure mechanisms of an-isotropic perfect and imperfect planar FCC (Face Centred Cubic) truss lattice metamaterials. Three types of imperfection have been considered in the numerical modelling, namely, distorted struts, missing struts, and strut diameter variation. In order to maintain constant stress triaxiality during the simulations, a novel numerical framework was developed to overcome computational difficulties within the existing numerical approaches beyond elastic region. Three modes of microscopic localization were observed in perfect and imperfect lattices before failure: crushing band, shear band and void coalescence. A clear separation exists between the three modes of localization depending upon the type and level of defects, as well as the stress triaxiality. Under compressive loading, all lattices fail owing to crushing band; the distorted lattices are prone to shear band localization with increase in distortion, whereas missing lattices majorly fail due to void coalescence at high missing struts defect. Strut diameter variation, within the range of the strut diameters selected, shows no significant influence on the macroscopic mechanical response and strain localization. This work may open the door for predicting failure mechanisms of imperfect lattices under variety of loading conditions.

Citation

Bhuwal, A. S., Liu, T., Ashcroft, I., & Sun, W. (2021). Localization and coalescence of imperfect planar FCC truss lattice metamaterials under multiaxial loadings. Mechanics of Materials, 160, Article 103996. https://doi.org/10.1016/j.mechmat.2021.103996

• Journal Article Type: Article
• Acceptance Date: Jul 12, 2021
• Online Publication Date: Jul 17, 2021
• Publication Date: 2021-09
• Deposit Date: Jul 21, 2021
• Publicly Available Date: Jul 18, 2022
• Journal: Mechanics of Materials
• Print ISSN: 0167-6636
• Electronic ISSN: 1872-7743
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 160
• Article Number: 103996
• DOI: https://doi.org/10.1016/j.mechmat.2021.103996
• Keywords: Mechanics of Materials; General Materials Science; Instrumentation
• Public URL: https://nottingham-repository.worktribe.com/output/5811834
• Publisher URL: https://www.sciencedirect.com/science/article/abs/pii/S0167663621002271