Numerical and experimental investigation of the joint stiffness in lattice structures fabricated by additive manufacturing. (November 2018)

• Record Type: Journal Article
• Authors: Dong, Guoying; Zhao, Yaoyao Fiona
• Is Part Of: International journal of mechanical sciences. Volume 148(2018)
• Page Start: 475
• Page End: 485
• Publication Date: 2018-11
• Subjects: Additive manufacturing -- Finite element analysis -- Lattice structure -- Mechanical property; Mechanical engineering -- Periodicals; Génie mécanique -- Périodiques; Mechanical engineering; Maschinenbau; Mechanik; Zeitschrift; Periodicals; 621.05
• DOI: 10.1016/j.ijmecsci.2018.09.014
• Languages: English
• ISSNs: 0020-7403

Abstract

Highlights: A joint stiffening element is proposed to simulate lattice structures fabricated by additive manufacturing. The influence of the joint on the stiffness of the lattice structure can be considered in the proposed model. A parametric study is conducted to quantify the influence of the joint on a certain lattice structure and to find the optimal parameters of the joint stiffening element. Three-point bend testing is conducted, and it shows that the accuracy is significantly improved by the proposed model for bending dominant lattice structures. The computational cost of the proposed model is much lower than the tetrahedral element model. Abstract: In this paper, a concept called joint stiffening element is proposed to represent the influence of the joint on the stiffness of lattice structures fabricated by additive manufacturing. Four parameters are defined in the proposed element to quantify the increment of the stiffness caused by the lattice joint. Then, three-point-bend testing is used to validate the proposed model. The lattice structures with Cubic-center and Vintiles topologies are designed and fabricated for the experiment. As-fabricated material properties are obtained by tensile specimens to eliminate the influence caused by the manufacturing process and to isolate the joint stiffening effect. The result shows that models with the solid element and the proposed element are both accurate, but the proposed model has a significantly less computational cost than the solid element model. Furthermore, compared to the beam element model, the proposed model can more accurately estimate the stiffness of lattice structures, especially for the Vintiles topology. It is also found that the joint stiffening effect is more significant on the bending dominant topology than the stretching dominant topology. Graphicalabstract :