Energy absorption characteristics of one, two and three layer multi-tube structures subjected to axial compressive loads

نوع: Type: thesis

مقطع: Segment: masters

عنوان: Title: Energy absorption characteristics of one, two and three layer multi-tube structures subjected to axial compressive loads

ارائه دهنده: Provider: Abdolsamad Gholivand

اساتید راهنما: Supervisors: Dr. Ali Alavi Nia

اساتید مشاور: Advisory Professors:

اساتید ممتحن یا داور: Examining professors or referees: Dr. Rahman Seifi and Dr. Hashem Mazaheri

زمان و تاریخ ارائه: Time and date of presentation: 2022/08/11

مکان ارائه: Place of presentation: Seminar 3

چکیده: Abstract: Thin-walled energy absorbers reduce collision damage by converting kinetic energy into the plastic deformation. In this research, the energy absorption properties of multi-tube thin-wall structures of one, two and three layers has been studied. The evaluation criteria of the structures were the specific absorbed energy and crushing force efficiency. After manufacturing according to the design conditions, aluminium cylindrical tubes were subjected to quasi-static axial loading at 10 mm/min and impact loading at 5-7 m/s velocities. Numerical simulation was carried out using LS-Dyna software. Due to the appropriate matching of simulation and experimental results, for further study, other modes were also simulated. Optimization was done using the response surface method using Design-Expert code. The purpose of optimization was to find structures with the highest specific energy absorption and crush force efficiency among multi-tube structures (one to seven tubes) consisting of four types of different cross-sectional geometries (circle, triangle, square and regular pentagon), multi-story (one, two and three). The results showed that the placement of the tubes affects the amount of specific absorbed energy. As the number of layers increases, the initial maximum force remained constant while the energy absorption increased. The optimal state is a three-layered seven-numbered structure with cylindrical tubes tangent to each other. In this case, the amount of specific absorbed energy increased by about 20%, and the crushing force efficiency increased by about 30% compared to the single-layered cylindrical tub

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