Session: 01-01-01: General Topics of Aerospace Structures

Paper Number: 121512

121512 - Enhancing Energy Absorption Capacity of Pyramidal Lattice Structures via Geometrical Tailoring and 3D Printing 

Pyramidal lattice structures have frequently been employed as the core material in the design of sandwich panels due to their impressive weight-specific strength. However, the struts in pyramidal lattice structures bend when subjected to axial, shear or bending loads, leading to non-uniform stress distributions and inefficient material volume utilization, especially at low relative densities. The current work introduces a geometrical tailoring scheme which provides the designer with additional parameters that can be adjusted to tune the cross-sectional properties of the lattice struts with the goal to obtain more uniform stress distributions across their thickness. Specifically, the conventional square and circular pyramidal lattice struts are reshaped into I-beam-like cross-sections, forming a tailored pyramidal lattice. These geometrically tailored pyramidal lattices were designed using CAD software and 3D printed via the Digital Light Processing (DLP) technique, which offers precise control over the micro-scale features of the lattice designs. The quasi-static compressive responses of the lattices were experimentally evaluated in terms of effective elastic modulus, collapse strength, and energy absorption capacity. Additionally, the collapse mechanisms of the geometrically tailored structures were assessed via a non-linear finite element analysis which was validated against the experimental evidence. Both the experimental and numerical results show that the geometrically tailored pyramidal lattice structures outperform their non-tailored counterparts in terms of energy absorption capacity. The results substantiate the validity of the geometrical tailoring strategy as the reported energy absorption capacity of the tailored pyramidal lattice structure exhibits a significant enhancement up to 64% and 15% respectively. The latter enhancements were attributed to the lateral buckling of struts, prompting the tailored struts to bend sideways during the collapse phase. The findings of this study demonstrate that tailoring the cross-sectional properties of lattice struts can significantly improve certain aspects of their mechanical response, which holds significance for the development of lightweight lattice-cored sandwich structures with enhanced weight-specific mechanical performance.

Presenting Author: Mohammed Ayaz Uddin Khalifa university

Presenting Author Biography: Mohammed Ayaz Uddin received his B.E. in Mechanical Engineering from Osmania University, India, and completed his MSc in Mechanical Engineering from the KFUPM in Saudi Arabia. He is currently pursuing his Ph.D. in Mechanical engineering at Khalifa University, United Arab Emirates. His research interests include Additive manufacturing, geometrically tailoring of standard structures, and tunable mechanical characteristics of lattice structures.