Energy Absorption Analysis in Tetrahedral and Three-Dimensional Pyramidal Lattice Structures

نوع: Type: Thesis

مقطع: Segment: masters

عنوان: Title: Energy Absorption Analysis in Tetrahedral and Three-Dimensional Pyramidal Lattice Structures

ارائه دهنده: Provider: Erfan Taherkhani

اساتید راهنما: Supervisors: M. Shaban (Ph. D)

اساتید مشاور: Advisory Professors: H. Mazaheri (Ph. D)

اساتید ممتحن یا داور: Examining professors or referees: A. Alavi Nia (Ph. D) - A. Pak (Ph. D)

زمان و تاریخ ارائه: Time and date of presentation: 2025

مکان ارائه: Place of presentation: 55

چکیده: Abstract: Lattice-based structures with rod-like struts have recently gained significant attention due to their adaptability in diverse applications, including biomedical sciences and aerospace engineering. Their repetitive design based on unit cells allows effective control and optimization of mechanical properties. In this thesis, tetrahedral and pyramidal structures, as the latest members of the BCC family, were investigated. Given the geometric complexity of these structures, conventional manufacturing methods are not feasible; therefore, 3D printing technology was employed for fabrication. To determine the mechanical properties of the base material, such as elastic modulus and yield strength, standard tensile specimens were fabricated using an FDM 3D printer with PLA+ filament and tested under uniaxial tension. Subsequently, two three-dimensional auxetic structures (tetrahedral and pyramidal) were produced and subjected to quasi-static in-plane compressive loading. Finite element models of the structures were developed in Abaqus software and validated against experimental data. To optimize energy absorption, design variables were identified, and a design of experiments was conducted using Design-Expert software by considering independent parameters such as structure height, strut diameter, number of layers, and structural type. Two configurations were examined: with a top plate and without a top plate, coded as TET, PYR, TEH, and PYB. The results indicated that the TET structure exhibited the highest energy absorption and superior mechanical performance, while the PYR structure showed the weakest behavior. The TEH and PYB structures, due to the absence of a top plate, absorbed less energy compared to their counterparts; however, their reduced volume may present advantages in specific applications. Furthermore, increasing the structural height accelerated failure and increased the likelihood of buckling. Overall, the TET structure demonstrated more uniform crushing behavior and a superior load–displacement response compared to the PYR structure, where crushing occurred layer by layer.

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