Lattice Structure: Modeling, Design, and Simulation

Restricted (Penn State Only)
Author:
Liu, Yuqin
Graduate Program:
Industrial Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
November 26, 2017
Committee Members:
  • Sanjay Joshi, Thesis Advisor
Keywords:
  • Lattice structure
  • Homogeneous
  • Safety Factor
  • Truss
Abstract:
An algorithm for designing and optimizing homogeneous lattice structure to support given load condition is presented. The approach is to homogenize the safety factor distribution by altering trusses parameters defining the lattice structure. The algorithm combines theoretical mechanics in the initial design section, and FEA method to optimize and verify the tests result. The Octahedral lattice structure is utilized as an example of the design and optimization algorithm. The initial design decides the lattice structure node locations, and the optimization process redistributes structure material to reach higher strength without adding or removing material at the whole structure level, this means each truss may have a different cross-section due to their functions. Modern additive manufacturing technology made the fabrication of such lattice structure to be possible. The reference parameters in optimization iterations are Safety Factor distribution and the Von-Mises stress. Material stress limit and design safety factor are determined outside the iteration loops. The optimized lattice structure and the traditional lattice structures are physically tested in an MTS compress test machine. The result for a 3×3×3 octahedral cells lattice structure shows the optimized lattice structure support 60% more load than the traditional homogeneous lattice structure at the same weight. The optimize/design algorithm could be applied to other lattice structures formed by nodes and or general structures.