Abstract
The paper describes experimental and computational testing of regular open-cell cellular structures behaviour under impact loading. Open-cell cellular specimens made of aluminium alloy and polymer were experimentally tested under quasi-static and dynamic compressive loading in order to evaluate the failure conditions and the strain rate sensitivity. Additionally, specimens with viscous fillers have been tested to determine the increase of the energy absorption due to filler effects. The tests have shown that brittle behaviour of the cellular structure due to sudden rupture of intercellular walls observed in quasi-static and dynamic tests is reduced by introduction of viscous filler, while at the same time the energy absorption is increased. The influence of fluid filler on open-cell cellular material behaviour under impact loading was further investigated with parametric computational simulations, where fully coupled interaction between the base material and the pore filler was considered. The explicit nonlinear finite element code ls-dyna was used for this purpose. Different failure criteria were evaluated to simulate the collapsing of intercellular walls and the failure mechanism of cellular structures in general. The new computational models and presented procedures enable determination of the optimal geometric and material parameters of cellular materials with viscous fillers for individual application demands. For example, the cellular structure stiffness and impact energy absorption through controlled deformation can be easily adapted to improve the efficiency of crash absorbers
Highlights
Materials with cellular structures are arousing great interest in modern engineering industry due to their favourable mechanical and thermal properties
The paper investigates the behaviour of closed- and open-cell cellular structures under uniaxial impact loading by means of computational simulations using the explicit nonlinear finite element code LS-DYNA
The computational simulations have confirmed that the size of the model and the number of the cells influence the macroscopic behaviour of cellular structure
Summary
Materials with cellular structures are arousing great interest in modern engineering industry due to their favourable mechanical and thermal properties. The purpose of the presented research study is characterisation of new advanced cellular materials with pore fillers under impact loading conditions considering high strain rates and large deformations. The computational models of regular closed- and open-cell cellular structures have been evaluated and validated. The computational models account for the fully coupled interaction between the base material and the pore filler. In this study cellular structures with various base materials and relative densities are studied, whereas fillers with different viscosities are considered. The influence of gas trapped inside the closed-cell cellular structure has been analysed with the representative volume element. The analysis of the viscous filler inside the pores of the open-cell cellular structures has been performed with the combination of the finite element method and the meshless method Smoothed particle hydrodynamics. The LS-DYNA code has been used to perform dynamic computational simulations
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