Research On Innovation Design And Mechanical Properties Of Combinatorial And Hierarchical Quasi-honeycomb Core Structure

With the continuous application of sandwich structure materials in the fields of ships,automotive,aerospace and other fields of high-end equipment,higher requirements are put forward for its load carrying capacity,energy absorption,failure and other performance.The traditional single sandwich structure not able to meet the design requirements under complex working conditions,and it is urgent to develop innovative lightweight structures with low cost,high efficiency,environment-friendly and energy-saving.Sandwich layer is an important part of sandwich structure.In this paper,the configuration mode of the traditional single honeycomb core structure is broken through,and the combination concept and hierarchical concept are combined to innovatively design combinatorial and hierarchical quasi-honeycomb core structure.The relative density function,equivalent elastic modulus and engineering application are studied by combining theoretical analysis,numerical simulation and experiment.The main research contents are as follows:(1)Combinatorial and hierarchical quasi-honeycomb core structure is innovated.Through the concept of combination,the quadrilateral,hexagonal and octagon are optimized form a combinatorial and hierarchical quasi-honeycomb core structure.From the perspective of bionics,the characteristics of frog bones and deep-sea fish bones are combined with the micro honeycomb sandwich structure,and the hierarchical concept is introduced to construct the combinatorial and hierarchical quasi-honeycomb core structure.(2)Study on mechanical properties of combinatorial and hierarchical quasi-honeycomb core structure.In order to better describe the characteristics of combinatorial and hierarchical quasi-honeycomb core structure,the length ratio is introduced.According to the evolution process of combinatorial and hierarchical quasi-honeycomb core structure,the mass of core structure and the equivalent mass of core structure are solved under the premise that the size factor meets the requirements of geometric evolution rules.The relative density function is derived by using the mass conservation principle.The variation laws of the combinatorial and hierarchical quasi-honeycomb core structure from first-level to n-level is explored,and the relative density function of the combinatorial and hierarchical quasi-honeycomb core structure is summarized.The equivalent mechanical model of combinatorial and hierarchical quasi-honeycomb core structure is established,and the equivalent mechanical parameters are derived by using the improved Gibson formula.(3)Analyse numerical simulation and experimental study of the combinatorial and hierarchical quasi-honeycomb core structure.By comparing the results of the numerical simulation and experimental organizational analysis to explore theoretical model of combinatorial and hierarchical quasi-honeycomb core structure.The structural optimization design of the combinatorial and hierarchical quasi-honeycomb core structure was carried out.The results show that the equivalent elastic modulus of the optimized structure increases by25.2%when the relative density decreases by 12.7%,which meets the goal of lightweight structural design.(4)The engineering application of combinatorial and hierarchical quasi-honeycomb core structure was studied.The combinatorial and hierarchical quasi-honeycomb core structure is filled with crash box.The energy absorption characteristics are analyzed.The results show that the 2^ndcrash box has a stable symmetric folding deformation mode compared with the 0^ercrash box and the 1^stcrash box.Its total energy absorption is much higher than traditional crash box,the 0^ercrash box and the 1^stcrash box.In summary,this paper introduces the concept of combination and hierarchy to innovate the configuration of traditional honeycomb core structure,and studies its equivalent mechanical properties and energy absorption characteristics.It is found that the combination of hierarchical concept and traditional honeycomb core structure not only improves the designability of honeycomb core structure,but also makes the combined honeycomb hierarchical core structure have good mechanical properties.The research results of this paper provide new ideas for innovative lightweight structure design,and solve the problem of lightweight and high strength incompatibility in lightweight design,which has important innovation significance.