A simple model for estimating the crack kinking angles of pure shear fracture of 3D printing polymers

Luoyu Roy Xu; Yuelong Jiang

doi:10.5802/crmeca.311

Article de recherche

A simple model for estimating the crack kinking angles of pure shear fracture of 3D printing polymers
[Modèle simple pour l’estimation des angles de branchement des fissures dans les ruptures en cisaillement pur des polymères imprimés en 3D]

Luoyu Roy Xu ¹ ; Yuelong Jiang ¹

¹School of Mechanical Engineering and Mechanics, Ningbo University, Zhejiang, China

Comptes Rendus. Mécanique, Volume 354 (2026), pp. 25-33

Abstract (VO)
Résumé

Shear fracture studies of three-dimensional (3D) printing polymers with interfaces were rarely reported due to their complicated mechanics and material issues. In this study, a short-beam shear fracture approach was employed to characterize the mode-II shear fracture toughness of polyamide specimens of three printing surface angles made with selective laser sintering (SLS). Results show that a pure shear crack only existed if the initial crack propagated along the printing interface. In other cases, initial cracks kinked right after crack initiation, so no valid shear fracture toughness was measured. A simple model based on linear elastic fracture mechanics including anisotropic fracture toughnesses was proposed to predict the crack kinking angles. The prediction agreed with the measurements well and was more reasonable than the prediction based on the maximum tensile stress criterion.

Les études sur la rupture par cisaillement des polymères imprimés en trois dimensions (3D) avec interfaces sont rares, en raison de la mécanique complexe impliquée et des problèmes liés aux matériaux. Dans cette étude, des expériences de rupture par cisaillement sur poutre courte ont été utilisées pour caractériser la résistance à la rupture par cisaillement (en mode II) d’échantillons de polyamide, présentant trois angles de surface d’impression, et réalisés par frittage laser sélectif (SLS). Les résultats montrent qu’une fissure ne peut se propager en cisaillement pur que si la fissure pré-existante se propageait elle-même le long de l’interface d’impression. Dans les autres cas, les fissures pré-existantes ont changé de direction juste après leur apparition, de sorte qu’aucune résistance à la rupture par cisaillement n’a pu être valablement mesurée. Un modèle simple basé sur la mécanique de la rupture linéaire élastique, incluant une tenacité anisotrope, a été proposé pour prédire les angles de branchement des fissures. La prédiction correspond bien aux mesures, et est plus raisonnable que celle basée sur le critère de contrainte de traction maximale.

Reçu le : 2025-01-24
Révisé le : 2025-06-18
Accepté le : 2025-06-18
Publié le : 2026-01-16

DOI : 10.5802/crmeca.311

Keywords: Shear fracture, Fracture toughness, 3D printing, Polymer, Interfaces
Mots-clés : Rupture par cisaillement, Résistance à la rupture, Impression 3D, Polymère, Interfaces

Affiliations des auteurs :

Luoyu Roy Xu ¹ ; Yuelong Jiang ¹

¹ School of Mechanical Engineering and Mechanics, Ningbo University, Zhejiang, China

Licence :

CC-BY 4.0

Droits d'auteur : Les auteurs conservent leurs droits

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     author = {Luoyu Roy Xu and Yuelong Jiang},
     title = {A simple model for estimating the crack kinking angles of pure shear fracture of {3D} printing polymers},
     journal = {Comptes Rendus. M\'ecanique},
     pages = {25--33},
     year = {2026},
     publisher = {Acad\'emie des sciences, Paris},
     volume = {354},
     doi = {10.5802/crmeca.311},
     language = {en},
}

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Luoyu Roy Xu; Yuelong Jiang. A simple model for estimating the crack kinking angles of pure shear fracture of 3D printing polymers. Comptes Rendus. Mécanique, Volume 354 (2026), pp. 25-33. doi: 10.5802/crmeca.311

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