Study On Mechanical Properties And Energy Absorption Mechanism Of The Mixed Cellular Material With Soft Matrix

The mixed cellular material with soft matrix is a new type of material with partially open and partly closed cells with pinholes,which has both excellent energy absorption characteristics under impact load and recoverability after unloading.Artificial cartilage bionic metamaterial(ACF)is a soft matrix material with micro-nano mixed cellular.At present,there are few studies on the mechanical properties of mixed cellular material with soft matrix.In this paper,a systematic study of mixed cellular material with soft matrix will be carried out to lay a foundation for research of mechanical properties and energy absorption mechanism,and to guide the research and application of this kind of material.The viscoelastic material model is widely to applied to simulate the macroscopic mechanical behavior of soft matrix materials(polymer materials,rubber,etc.),but the relationship between the impact performance of viscoelastic materials and the viscoelastic properties of the material,such as elastic modulus,viscosity coefficient and other parameters,is not clear.In this paper,based on the flexible discrete model,the impact theoretical model of viscoelastic materials is established,the differential equations of motion of the impact system are solved,and the expressions of the relationship between the maximum displacement,the maximum interaction force,the maximum impact force and energy absorption and the properties of the material itself are obtained,which provide a theoretical basis for the application of viscoelastic materials in the field of protection.In addition to the study of the theoretical model,experimental characterization,and simulation analysis of the mechanical properties of the material are also carried out.Firstly,the microstructure of ACF material is characterized,and it is found that this material has a micro-and nano-scale cytosolic structure,and unlike the general open-and closed-pore materials,some of the cytosolic pores of ACF material are interconnected with each other,and the concept of soft matrix hybrid cytosolic material is proposed based on this interconnected cytosolic structure.Based on this finding,the relaxation and dynamic mechanical properties of the material were characterized.In addition,in order to better investigate the effect of material microstructure on the mechanical behavior of the material,the mechanical properties of the ACF matrix material were characterized using the same experimental means.Then,based on the mechanical response of the matrix material under different working conditions,the "Hyperelastic-Hysteresis-Viscoelastic" stress-strain relationship was obtained by using mathematical and finite element software,and the accuracy of the material intrinsic relationship was verified by comparing the experimental and simulated curves.Finally,based on the simple single-cell and multi-cell models,the effects of air on the compressive and impact properties of the material are investigated using the ABAQUS/CEL method,and the effects of air and matrix stiffness on the mechanical properties and energy absorption characteristics of the material are discussed.