Experimental and Numerical Study on the Energy Absorption of a Three-Dimensional Auxetic Structure

نوع: Type: Thesis

مقطع: Segment: masters

عنوان: Title: Experimental and Numerical Study on the Energy Absorption of a Three-Dimensional Auxetic Structure

ارائه دهنده: Provider: Ashkan Mosayebi

اساتید راهنما: Supervisors: Hashem Mazaheri

اساتید مشاور: Advisory Professors: Mehdi Shaban

اساتید ممتحن یا داور: Examining professors or referees: Ali Alavi Nia-Rahman Seifi

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

مکان ارائه: Place of presentation: 55

چکیده: Abstract: Periodic structures with complex geometries, such as triply periodic minimal surfaces (TPMS), have emerged as promising candidates for energy absorber design in engineering applications due to their unique mechanical properties. In this study, two types of structures, Gyroid and Schwarz, were investigated with the aim of evaluating and optimizing their energy absorption performance. Initially, samples of both structures with dimensions of 80×80×80 mm and an initial wall thickness of 2 mm were designed in SolidWorks and fabricated using an FDM 3D printer with PLA+ material. Subsequently, compression tests up to full densification were carried out at a crosshead speed of 3 mm/min using a Sentam 15-ton press. Numerical modeling was then performed in Abaqus, and the simulation results were validated against the experimental data. Thereafter, the effects of varying wall thickness (from 1 to 4 mm) and applying scaling in the Y-direction (ranging from 1 to 3 times) on the energy absorption indices—Energy Absorption (EA), Specific Energy Absorption (SEA), Specific Energy Absorption by Volume (SEAV), Mean Crushing Force (MCF), Peak Crushing Force (PCF), and Crushing Force Efficiency (CFE)—were examined for both structures. The results of this analysis were transferred to Design-Expert software, and optimal parameter values for maximizing SEA were obtained using the Central Composite Design (CCD) method. Furthermore, multi-objective optimization was conducted by simultaneously considering SEA, PCF, and MCF to achieve a balanced performance configuration. The findings indicated that increasing wall thickness enhances the energy absorption capacity of the structures. Under redesign with Y-direction scaling, the Schwarz structure achieved its best performance at a scale factor of 3, while the Gyroid structure performed best at a scale factor of 2. Considering only the SEA index, the optimal values for Schwarz and Gyroid were obtained at scale factors of 2.6 and 2.5, and wall thicknesses of 2.5 mm and 3.3 mm, respectively. In

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