Structural Design And Application On Improving Out Of Plane Compression Performance Of Nomex Honeycomb

In order to explore the structural design method to improve the out of plane performance of Nomex honeycomb,stacked multilayer Nomex honeycomb and Nomex honeycomb filled with carbon fiber tube and aluminum tube are studied and applied to the energy absorption device of railway vehicles.The following conclusions are obtained:(1)The superposition of Nomex honeycomb with the same specification can obtain high thickness composite honeycomb with similar performance,which solves the problems of instability of single honeycomb;The superposition of Nomex honeycomb with different specifications deforms step by step with the strength from weak to strong,producing a controllable hierarchical response.Changing the combination order can control the time sequence of each layer deformation in the compression process;The proportion of the number of honeycombs determines the strain proportion experienced by the platform stress,which can orderly control the step energy level.(2)The Nomex honeycomb filled with CFRP(Carbon fiber reinforced plastics)tube can use the compression residue to maintain stable energy absorption and improve the specific energy absorption,but there is an upper limit of stable energy absorption;The performance of CFRP tube dispersed distribution is better than that of concentrated distribution;Under load,honeycomb folding,CFRP tube expansion,finite element and theoretical model provide the simulation and calculation of mechanical properties.The performance of the large-scale embedded structure is more stable,and the series superposition of the structure can realize gradient deformation.The CFRP tube produces fine indentation on the interlayer panel and presents funnel-shaped tear.(3)The Nomex honeycomb filled with aluminum tube can greatly increase the energy of Nomex honeycomb,and there is no upper limit of stable energy absorption,but the aluminum tube has low stability and is easy to lose stability,resulting in reduced energy absorption.Asymmetric deformation occurs in the concentrated distribution of aluminum tubes,and the folds are embedded with each other to produce time series compensation effect.Symmetrical deformation occurs in the dispersed distribution of aluminum tubes,and similar single tube fluctuations occur in the same phase of folds.Therefore,the energy absorption of concentrated distribution of aluminum tubes is better than that of dispersed distribution.The Nomex honeycomb filled with aluminum tube can also realize gradient deformation.(4)Stacked multilayer Nomex honeycomb structure and Nomex honeycomb filled with CFRP tube and aluminum tube structure are applied to the energy absorption device at the front end of railway vehicles.A thin-walled tube energy absorption device with stacked multilayer Nomex honeycomb filled with tube as the core is proposed to achieve the purpose of controllable deformation sequence and compression response.Stacked multilayer Nomex honeycomb,Nomex honeycomb filled with CFRP tube structure and Nomex honeycomb filled with aluminum tube structure can effectively improve the out of plane compression performance of Nomex honeycomb and expand the application of Nomex honeycomb.