Study On The Design And Energy Absorption Characteristics Of Turtle Shell Like Buffer Structure

With the rapid development of aerospace and transportation,the demand for buffer structures for vehicles such as automobiles,airplanes,and spacecraft is increasing.In order to ensure the safety of personnel and equipment,it is of great scientific significance and application prospect to design a lightweight and good energy absorbing buffer structure.With the continuous deepening of research,traditional structural design methods have been difficult to meet this demand,while bionic structure is a method to study the structure and characteristics of organisms and use them as the basis for innovative design.In the design of crashworthiness structures,the application of structural bionics can not only provide new design ideas but also create more efficient structures that absorb energy.Due to its advantages such as light weight,high strength,and good cushioning performance,turtle shells have become a hot bionic object in structural design in recent years.Based on the principles of bionics,this paper proposes a design scheme of a bionic turtle shell cushioning and energy absorbing structure,using a lightweight and high-strength turtle shell in nature as a bionic prototype.The method of combining "shape function material process simulation" was used to study the energy absorption characteristics of structures.The main research contents are as follows:(1)Analysis of the macro and micro structure and geometric characteristics of the Brazilian turtle shell.Using the Brazilian turtle shell as a bionic prototype,the cross section of the shell was observed using SEM and stereomicroscope,and the macro and micro structure information of the shell structure,including shell wall thickness,arrangement,and morphological characteristics,was obtained.Using Micro-CT to scan the structure of the turtle shell,and using the computer image processing software Avizo,the geometric morphology of the scanned turtle shell was extracted,and the morphological parameters of the cancellous bone layer of the turtle shell were quantitatively analyzed.(2)A novel design method for adjustable bionic structures is proposed.For the design of a turtle shell like buffer structure,a solid model construction method is used,based on Voronoi principle,and the Grasshopper plug-in is used for parametric design.The model is adjustable by adjusting three structural design parameters,namely,irregularity,pore number,and pore edge diameter.The model was prepared using selective laser melting molding technology.In order to prepare a solid model with good energy absorption characteristics and microstructure,316 L was used as the material,and the optimal molding process parameters for printing were determined through orthogonal experimental analysis to optimize the density.(3)Energy absorption performance analysis of turtle shell like buffer structure based on response surface method.Using the optimized process parameters to print the turtle shell buffer structure,the response surface method was used to take the structural irregularity,the number of pores,and the diameter of pore edges as the levels,and the total energy absorption,specific energy absorption,and platform stress as the response values.The influence of structural parameters on the energy absorption effect was studied through quasi-static compression experiments.A multivariate nonlinear prediction model of the structure was established with the energy absorption effect as the optimization goal to obtain the optimal energy absorption structural parameters.(4)Finite element simulation and synergy analysis of turtle shell buffer structures.Static compression numerical simulation of turtle shell buffer structures was performed using ABAQUS finite element analysis software.Due to the excellent energy absorption characteristics of bionic structures,a structure filled with square thin-walled tubes was further proposed to study the synergy between the turtle shell buffer structure and the external square thin-walled tubes.