Studying the effect of the arrangement of thin-walled structures on improving their energy absorption characteristics and decreasing damage on the main structure

نوع: Type: Thesis

مقطع: Segment: masters

عنوان: Title: Studying the effect of the arrangement of thin-walled structures on improving their energy absorption characteristics and decreasing damage on the main structure

ارائه دهنده: Provider: Ali Saki

اساتید راهنما: Supervisors: Ph.D. Ali Alavi nia

اساتید مشاور: Advisory Professors:

اساتید ممتحن یا داور: Examining professors or referees: Ph.D. Hashem Mazaheri - Ph.D. Mahdi Shaban

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

مکان ارائه: Place of presentation: 54

چکیده: Abstract: Thin-walled energy-absorbing structures are a type of irreversible energy absorbers that dissipate the energy generated by loading through plastic deformations, thereby reducing damage to the main structure. This study examines the effects of various Parameters, including the number of layers, material type, number of tubes per layer, cross-sectional geometry, layer height, and lateral spacing of the tubes, on the specific energy absorption (SEA) of the absorber under quasi-static loading. Two different approaches were used for the analysis. In the first approach, the energy absorption characteristics of the absorbers were evaluated independently, without considering the main structure. In the second approach, their effects on energy absorption were analyzed while considering the damage to the main structure. Experimental tests and numerical simulations were conducted to investigate these Parameters. The experimental design and optimization were performed using the Taguchi method in Minitab software, while the simulations were carried out using LS-DYNA. The results showed that the Taguchi method had significant errors in some cases. Therefore, a logical analysis of the data and a comparison with previous studies were conducted. The findings indicate that the main structure must always be considered when designing and analyzing energy absorbers. In the analyses where the main structure was not considered, increasing the number of absorber layers from one to two resulted in a 7.7% increase in SEA, while increasing from two to three layers led to an 8.9% increase. However, when the effects on the main structure were considered, an optimal number of layers was observed. The SEA of a two-layer absorber was 42% greater than that of a single-layer absorber, but increasing the number of layers from two to three resulted in a 15% reduction in SEA compared to the two-layer case. The strength of the main structure should always be higher than that of the absorbers. In cases where the main structure has low strength, it should be enclosed within a protective structure, and the absorber should be designed accordingly. Additionally, the number and height of tubes in each layer significantly influenced the damage to the main structure. In a single-layer absorber, reducing the number of tubes from four to one led to a remarkable 49,000% increase in SEA.

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