Lightweight lattice structures are an important class of cellular structures with high potentials for multifunctional applications. Considering load-bearing requirements, truss buckling is one of the main failure mechanisms
for low density and slender lattice structures. Critical buckling loads can be increased by modifying the profile
of a truss. In this paper, we present a shape design method to optimize the critical buckling loads for lattice
cores with free-form trusses. The free-form truss is represented by Fourier series and implicit surfaces, having
smooth truss diameter variations and truss joints. The optimized truss profile is obtained by solving a parametric shape optimization problem with Fourier series coefficients as design variables. The method is used for designing optimized 1D columns and 3D Kagome lattice cores for sandwich panels. The numerical results predict 26.8% and 20.4% improvements of the critical buckling loads for 1D columns and 3D Kagome lattice cores compared to their uniform counterparts of the same mass, respectively. The optimized structures include complex smooth and curved geometries that arewell suited for additive manufacturing because of the greater design freedom. Finally, the initial and optimized lattice cores are additively manufactured and tested. The experimental results validate the effectiveness of the proposed method.
License type:
http://creativecommons.org/licenses/by-nc-nd/4.0/
Funding Info:
The authors further acknowledge the support from the Agency for Science, Technology and Research and the Science and Engineering Research Council of Singapore through the Additive Manufacturing Centre Initiative (SERC Grant no. 142 68 00088).