Study On Mechanical Properties And Energy Absorption Of 3D Printed Elastic Three-dimensional Structures

Honeycomb structures are widely used in energy absorption applications such as vehicle crash mitigation,protection of vulnerable parts and personal protection.It can absorb large amount of energy without creating high levels of stress on the protected object in the field.Current research tends focus on the brittle materials,which limits its applications in areas such as shock absorption and personal protective equipment.In addition,the regular honeycomb structure has high energy absorption,the corresponding stress range is relatively narrow.It is necessary to explore the honeycomb structure designs with deep understanding to support the wide range of load fluctuations in real life.In this study,we used elastomers such as polydimethylsiloxane and thermoplastic polyurethanes as experimental materials,and fabricated different honeycomb structures using 3D printing.The deformation modes,mechanical properties and energy absorption properties of regular and gradient honeycomb structures were investigated by both experiments and numerical simulations.The main contents of this paper are as follows:Using regular honeycomb structure,we studied 1)the material preparation and 3D printing process to fabricate honeycomb structure;2)the effects of element type on the deformation mode,mechanical properties and energy absorption of the honeycomb structure by quasi-static compression test;3)the influence of relative density and material was explored by taking the hexagonal honeycomb structure as the main research object;4)the repetitive compression performance of the elastic honeycomb structure;and 5)the comparison of the regular honeycomb structure and random foam material with the same relative density.For the gradient honeycomb structure,the parameters of the constitutive model of polydimethylsiloxane(PDMS)were firstly determined by means of uniaxial compression experiments.Then,compression experiments were carried out on the reduced gradient honeycomb structure and the corresponding finite element model was established to verify the parameters of the PDMS constitutive model and the reliability of the finite element model.Finally,a variety of gradient honeycomb structures were designed for studying the effects of gradient distribution and cell arrangement on deformation mode,mechanical properties and energy absorption via numerical simulation,compared to those from regular honeycomb structures.Through the above researches,the feasibility of the customized honeycomb structure was verified,and the effects of relative density,material and cell type on the performance of the honeycomb structure were studied,and the mechanical properties and energy absorption of the honeycomb structure were further adjusted by introducing a gradient structure.This research result provides a reference and guidance for designing advanced lightweight cellular elastic structures,and provides a theoretical basis for the application of elastic honeycomb structures in the fields of shock absorption and human protection.