Mechanical Characteristics Of A Circular Nested Ring Energy Absorber Under Transverse Load

The issue of crashworthiness of structures is an important part in the design of various modern vehicles.To meet safety requirements and to protect passengers or internal equipment,energy absorbers can be arranged in the structure.Thin-walled metal tubes are widely used as traditional energy-absorbing members in the automotive,construction,aerospace,and military industries.In the pursuit of structural lightweight today,how to maximize the energy dissipation capacity with limited materials has been a key concern for many researchers and structural engineers.Since the plastic deformation of transversely collapsed circular tubes is confined to the vicinity of the plastic hinge generated during the collapse process,the energy dissipated through the transverse collapse of circular tubes is limited and inefficient.The nested ring system,which uses rings as the basic components and nests them together by simple connecting means to work in concert,can substantially increase the energy absorption capacity without significantly increasing the cost.In this paper,the mechanical properties of triple intermittent nested ring TINT and triple continuous nested ring TCNT,which consist of three circular rings,under quasistatic transverse crushing loads are mainly investigated from three aspects: experiments,theoretical derivations and numerical simulations.The basic mechanical properties of the6063 aluminum alloy material were tested on a universal testing machine,and compression tests were conducted on the circular ring and the two nested ring systems,respectively.For the crush problem of circular ring,not only the theoretical models of "De Runtz63" and "Reid78" are introduced in detail,but also the numerical simulations are carried out using the finite element software Abaqus.For the nested ring system,the influence of the diameter and wall thickness parameters of each component on the overall force-displacement curve and specific energy absorption is emphasized,and a simple and easy theoretical prediction equation is established,which can give more accurate prediction for the model after variable parameters from the known starting point.Some practical programs of Python scripts are given in the appendix,which are expected to be helpful for related researchers.Considering the unpredictability of the loading direction in practical applications,the authors have constructed an asymmetric deformation pattern by rotating the nested ring system as a whole to form a new configuration and have explained the effects caused by the rotating elements from the perspective of the force-deformation mechanism.The completion of these works can serve as a reference for the design and installation of nested ring structures.