Design of Buckling Resistant Lattice Cores and Structures

Abstract

Lightweight lattice materials based on Triply Periodic Minimal Surfaces (TPMS) offer high stiffness-to-weight ratios, making them ideal for aerospace applications. However, at low relative densities, they are susceptible to buckling. This study addresses the limited research on the buckling behavior of hierarchical and multi-material lattices. A hierarchical design strategy was applied by embedding TPMS geometries (Gyroid, Primitive, Diamond, and IWP) into 2D lattice frameworks (Square, Hexagonal, Circular) to enhance buckling resistance. Twelve hierarchical columns were 3D printed and tested, with the Hexagonal-Primitive design showing the best balance of printability, buckling load, and print time, while Hexagonal-Diamond achieved the highest critical buckling load. Linear eigenvalue buckling simulation was also conducted on the hierarchical columns. Inspired by bamboo, multi-material columns and sandwich structures using PLA and nylon in varying proportions were also 3D printed and tested to test the feasibility of tuning the critical buckling load and energy absorption. The buckling resistance of multi-material columns and out-of-plane compressive strength of the multi-material sandwich structures showed tunability with PLA percentage, but energy absorption showed less predictable trends with nylon content. In-plane compression strength of the multi-material sandwich structures were also not tunable. A key outcome of this study is the development of reference tables to assist engineers and designers in selecting optimal material proportions to achieve desired critical buckling loads and energy absorption.

Date of Award	2025
Original language	American English
Supervisor	Kamran Khan (Supervisor)