Mechanical performance and fatigue life prediction of lattice structures: Parametric computational approach

Abstract

Additive manufacturing (AM) highly complex lattice structures with exceptional engineering properties are of special interests for a wide range of engineering applications including biomedical (implant, scaffold), automotive (shock-absorbing, load sensors) and civil engineering (protective layers). This research focuses on developing a numerical framework to predict the mechanical and fatigue properties of lattice structures with various relative densities and architectures. The relationship between geometry parameters and relative density of four lattice structures is investigated. Finite Element Analysis (FEA) is employed to simulate uniaxial compression test so that the elastic modulus and yield strength of lattices are evaluated. Parametric studies on hundred designs for each lattice are conducted to obtain associated design maps. Among the lattice structures investigated, the Simple Cubic (SC) unit cell shows the highest elastic modulus and yield strength at any relative densities, while these properties of Body Centred Cubic (BCC) unit cell is the lowest. Numerical results also reveal the nonuniform distributions of strain & plastic dissipation energy between layers, when multilayer lattice structures are subjected to compression. The fatigue property of lattice structures is also predicted numerically showing the dependence on both relative density and unit cell topology. The normalised fatigue behaviour of SC and Simple Cubic Body Centred Cubic (SC-BCC) are independent of relative density, while Face Centred Cubic (FCC) and BCC are sensitive to its relative density.