Lattice infill strategies for topology optimisation towards achieving lightweight designs for additive manufacturing: Structural integrity, and manufacturing consideration

Abstract

Lightweight designs have become imperative in aerospace applications, driven by the increasing focus on green aviation and the ever-growing need to reduce aviation emissions. The complex lightweight designs are typically limited by the manufacturing capability of the conventional process. Consequently, additive manufacturing has emerged as a vital tool for producing these lightweight designs, owing to its inherent design freedom as a consequence of its layer-by-layer approach. The current study explores the different lightweight design strategies derived from topology optimisation (TO) and internal lattice structure for aerospace applications. The proposed lightweight designs were examined for their mechanical performance and additive manufacturing-specific design constraints, such as support structure requirements and processing efforts. The optimal lattice infill was determined by comparing the mechanical properties of different skeletal and sheet-type triply periodic minimal surface lattice structures. Among the different lattice structures tested in the current study, the sheet-type diamond lattice structure emerged as the most suitable option for infill due to its superior mechanical properties. The TO results, coupled with the functionally graded diamond lattice structures, exhibited the best mechanical performance, yielding a maximum weight reduction of 24.3 % for bracket A and 52.5 % for bracket B.