Fatigue properties of triangular and octet-truss lattices

  • Yifan Li

Student thesis: Doctoral ThesisDoctor of Philosophy (PhD)

Abstract

Lattice structures provide high stiffness, strength and toughness at low density, which allows them to be used in different applications. In real applications, lattice structures are often under cyclic load. Numerous lattice structures are anisotropic, and their mechanical properties vary with cell orientations. Therefore, it is necessary to study the orientation effects on lattice fatigue. In this thesis, the fatigue properties of two lattice structures are investigated
in different cell orientations. The two types of topologies in this research chosen to be twodimensional triangular lattice and three-dimensional octet-truss lattice, because these two lattice structures, as stretching-dominated lattices, have great potential to be used in loadbearing applications. Additive manufacturing technique was used in this thesis to fabricate lattice with complex geometry.

From this dissertation, it can be found that the crack paths and crack growth rates of these two lattice structures heavily depend on the orientation. The analytical analysis indicates that the fatigue strength exponent of different lattices is independent of cell topology and orientation. While the fatigue strength coefficient of different lattices is highly dependent on the cell topology and lattice orientation.
Date of Award13 Sept 2022
Original languageEnglish
Awarding Institution
  • The University of Bristol
SupervisorMartyn J Pavier (Supervisor) & Harry Coules (Supervisor)

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