Experimental and numerical investigation on enhancing capped-end tube energy absorption capacity by orifice effect

This work proposes a method of energy absorption via phase change material (PCM)-filled circular tubes with caps and orifices on their end surfaces. As a novel method of energy absorption, energy absorbers were filled with a squeezable material. These filled tubes were anticipated to offer superior energy absorption performance than hollow tube systems thanks to energy dissipation during material squeezing through orifices. It has been experimentally studied how these tubes react when crushed by quasi-static lateral force. We used a hemi-cylindrical indenter to laterally compress the samples. Using systematic case design (SCD) and finite element (FE) method, we were able to provide guidelines for the effect of geometrical parameters of filled tubes to be employed as energy absorbers under lateral compression. Commercial FE analysis software (LS-Dyna) was used to develop the FE model, which was then validated by experimental results. Specific energy absorption capacity (SE) and force-displacement curves of filled tubes were derived as a function of geometrical parameters including thickness, diameter, and orifice size. A parametric study was conducted to evaluate the principal and interactive effects of geometrical factors on the SE. In conclusion, we proposed an empirical formulation of energy ab-sorption as a function of geometrical factors for a PCM-filled capped-end tube that can predict energy absorption with more than 95% accuracy. Validation was further achieved by comparison with analytical method.