Plastic and energy absorption behavior of compressed circular rings with locally nanocrystallized segments

By utilizing the technology of surface nanocrystallization, the distribution of mechanical properties on metal structures can be changed. In this paper, a theoretical study is presented to investigate the large plastic deformation and energy absorption behavior of circular rings with locally nanocrystallized segments crushed between two rigid, flat plates. The theoretical results are compared with the finite element analysis and a good agreement is obtained when the structural plastic deformation is not too large. The results show that the deformation modes of locally nanocrystallized circular rings are quite different from those of circular rings made of conventional coarse-grained poly-crystalline materials. The dependence of load-deflection relationship and typical energy absorption metrics of circular rings on several key material parameters and distribution strategy of locally nanocrystallized segments is discussed. Through properly designing the distribution of locally nanocrystallized segments, the crushing behaviors of circular rings can be optimized and the comprehensive energy absorption performance can be significantly improved. The present theoretical study can serve as guidance for developing superior energy absorbers utilizing modern advanced material processing techniques.