Experimental research of absorption properties of rigid foam filled circular seamless tube energy absorber under quasi-static axial load

The aim of this research work is investigations of absorption characteristics of a circular seamless tube collision absorber filled by rigid polyurethane (PU) foam under axial load. Shrinking of circular tube passing through cone bushing starts after absorber is activated at the moment of collision. The energy absorption realises in three ways: elastic-plastic deformation of the tube wall, friction between absorption elements and compression the rigid PU foam inside the tube. Using rigid PU foam, as the seamless tube filler, in the process of collision energy absorption increases absorption power in comparing to with only empty tube, as well as gives gradual increases of deformation resistance during deformation process. Experimental research was prepared and realized in the laboratory using the scaled samples. The effect of rigid PU foam, configuration of absorber filled by PU foam on the absorption power and manufacturing technology of the samples, are considered and discussed in this paper. The results indicate that the shrinking foam filled tube absorber has for about 18% bigger absorption power than the empty one. Formation of numerical model and numerical analyses of shrinking foam filled tube absorber were realized using ANSYS software package. Force vs. stroke (F(s)) diagrams obtained by tests and numerical analyses are in a good correlation which confirms formed numerical model as a suitable for further quasi-static analyses and for dimensioning the similar types of absorber.