Papers by Keyword: Lattice Material

Abstract: The ductile fracture behavior of two-dimensional imperfect lattice material under dynamic stretching is studied by finite element analyses (FEA). Three isotopic lattice materials, including the regular hexagonal honeycomb, the Kagome lattice and the regular triangular lattice, are taken into account, which are made of an elastic/visco-plastic metal material. Two typical imperfections (vacancy defect and rigid inclusion) are introduced separately. The numerical results reveal novel deformation modes and crack growth patterns in the ductile fracture of lattice material. Various crack growth patterns as defined according to their profiles, such as “X”-type, “Butterfly”-type, “Petal”-type. Crack propagation could induce severe material softening and plastic dissipation of the lattices. Subsequently, the effects of the strain rate, relative density, microstructure topology, and defect type on the crack growth pattern, the associated macroscopic material softening and the knock-down of total plastic dissipation are investigated.

Abstract: This paper presents a new method for the damage localization and severity estimate for lattice material based on substructure modal energy. The significant advantage associated with new method over traditional modal energy methods is that the spatially complete mode shape isn’t needed. Additionally, the new method does not require the analytical and measured modes to be consistent in scale, or to be normalized. Numerical studies in this paper are conducted for lattice material based on synthetic data generated from finite element models.

Abstract: Numerous methods have recently emerged for fabricating cellular lattice structures with unit cells that can be repeated to create 3D space filling systems with very high interconnected pore fractions. These lattice structures possess exceptional mechanical strength resulting in highly efficient load supporting systems when configured as the cores of sandwich panels. These same structures also provide interesting possibilities for cross flow heat exchange. In this scenario, heat is transported from a locally heated facesheet through the lattice structure by conduction and is dissipated by a cross flow that propagates through the low flow resistant pore passages. The combination of efficient thermal conduction along the lattice trusses and low flow resistance through the pore channels results in highly efficient cross flow heat exchange. Recent research is investigating the use of hollow truss structures that enable their simultaneous use as heat pipes which significantly increases the efficiency of heat transport through the lattice and their mechanical strength. The relationships between heat transfer, frictional flow losses and topology of the lattice structure are discussed and opportunities for future developments identified.