Improving energy absorption and failure characteristic of additively manufactured lattice structures using hollow and curving techniques
Journal article
Authors/Editors
Strategic Research Themes
Publication Details
Author list: Disayanan, Disaya; Buntornvorapan, Pattarapong; Sukprasertchai, Thammayuth; Uthaisangsuk, Vitoon
Publisher: Elsevier
Publication year: 2024
Journal: Composite Structures (0263-8223)
Volume number: 337
ISSN: 0263-8223
eISSN: 1879-1085
Languages: English-Great Britain (EN-GB)
Abstract
Strut-based lattice structures of various types exhibited a common critical issue, namely, high tensile stress concentration occurred at node-to-strut sites, which often led to lowered energy absorbability as compared to triply periodic minimal surfaces structures. Therefore, this work aimed for improving the Octet-truss structure by a combined technique using hollow core and varying cross-section ratio. Firstly, test specimens were fabricated using a stereo-lithography based additive manufacturing of photopolymer hard resin. Elastic-plastic properties and damage criterion of the used polymer were experimentally determined and applied for finite element models. Validation by compressive tests of lattice samples showed deviations of stress–strain responses less than 12%, in which local deformation and subsequent damages were fairly predicted. Afterwards, finite element simulations of designed lattice structures subjected to compressive, combined shear, shear and tensile loads were performed and obtained stress–strain characteristics including total absorbed energies and deformation behaviors were studied. Under uniaxial compression and combined shear loads, modified Octet-truss structures exhibited considerable increases of energy absorptions up to 173% and 116%, respectively, and stress–strain responses were more stable. On the other hand, by tension mode peak stresses and elongations could be enhanced about 41% and 11%, accordingly. The improved performances of proposed strut-based structures were comparable to those of triply periodic minimal surfaces diamond structure. This was due to that local stress distributions in the structure became more uniform and previously dominated tensile stresses were switched to compressive stresses. Therefore, occurrences of shear bands and plastic hinges could be effectively inhibited. © 2024 Elsevier Ltd
Keywords
Octet-truss, Photopolymer resin, Stereolithography (SLA), Strut-based lattice structure
Contact Information