This paper investigates the relationship of energy absorption between individual tube and nested tubes system in order to provide an equivalent design method for engineers. Firstly, both analytical and numerical methods were presented to analyze single tube under lateral point-loading compression, and the influences of material model and tube dimensions on energy absorption was studied. Secondly, an energy absorption system consisted of nested tubes was equivalently modeled by the combination of single tube in parallels or/and in series, and the resultant deformation and energy absorption were derived analytically by the present method. Several typical examples were verified numerically. It also discussed the relationship between structural effectiveness and solidity ratio for tube system and its components. Finally, a nested tubes system was optimized based on the requirements of installation space, crush distance and energy absorption capability.Copyright © 2011 by ASME