Evaluating Lattice Mechanical Properties for Lightweight Heat-Resistant Load-Bearing Structure Design

Area of Science:

• Materials Science
• Mechanical Engineering
• Additive Manufacturing

Background:

• Aircraft components require high strength-to-weight ratios and mechanical performance, especially under heat-resistant conditions.
• Lattice topology optimization is a key strategy for achieving lightweight and high-performance designs.
• Selecting the appropriate lattice structure is critical for optimizing mechanical properties based on stress environments.

Purpose of the Study:

• To evaluate and compare the mechanical performance of various metal lattice and triply periodic minimal surface (TPMS) structures.
• To identify the most suitable lattice type for heat-resistant, unidirectional load-bearing aircraft components.
• To provide a design basis for lattice selection in topology optimization.

Main Methods:

• Designed and manufactured six lattice types (BCC, BCCZ, honeycomb, gyroid, primitive, I-WP) at relative densities of 40-80% using Inconel 718 via selective laser melting (SLM).
• Conducted static tensile testing on all manufactured specimens.
• Analyzed deformation behavior based on an exponent value 'n' and structural characteristics.

Main Results:

• Honeycomb lattice structures demonstrated the best overall strength, toughness, and stiffness.
• A notable increase in toughness was observed in primitive and honeycomb lattices at specific density transitions (70-80% and 50-60%, respectively).
• Deformation behavior was categorized based on the exponent value 'n': stretching-dominated (n<0.3), bending-dominated (n>0.55), and stretching-bending-dominated (0.3

Conclusions:

• Honeycomb lattices are highly suitable for optimizing heat-resistant, unidirectional load-bearing aircraft structures.
• The study offers a foundational framework for selecting optimal lattices in topology optimization based on performance and deformation characteristics.
• Understanding lattice deformation mechanisms aids in predicting and enhancing structural performance.