Using Finite Element Approach for Crashworthiness Assessment of a Polymeric Auxetic Structure Subjected to the Axial Loading

Ali Farokhi Nejad,Michal Petrů,Mohd Yazid Yahya,Mozafar Shokri Rad,Roozbeh Alipour,Seyed Saeid Rahimian Koloor

doi:10.3390/polym12061312

Abstract

Polyurethane foams are one of the most common auxetic structures regarding energy absorption enhancement. This present study evaluates the result reliability of two different numerical approaches, the H-method and the P-method, to obtain the best convergence solution. A polymeric re-entrant cell is created with a beam element and the results of the two different methods are compared. Additionally, the numerical results compare well with the analytical solution. The results show that there is a good agreement between converged FE models and the analytical solution. Regarding the computational cost, the P-method is more efficient for simulating the re-entrant structure subjected to axial loading. During the second part of this study, the re-entrant cell is used for generating a polymeric auxetic cellular tube. The mesh convergence study is performed on the cellular structures using the H- and P- methods. The cellular tube is subjected to tensional and compressive loading, the module of elasticity and Poisson’s ration to calculate different aspect ratios. A nonlinear analysis is performed to compare the dynamic response of a cellular tube versus a solid tube. The crashworthiness indicators are addressed and the results are compared with equivalent solid tubes. The results show that the auxetic cellular tubes have better responses against compressive loading. The primary outcome of this research is to assess a reliable FE approach for re-entrant structures under axial loading.

Highlights

Modern technology requires new physical material properties
The different approaches to FE simulation were proposed to evaluate the effectiveness of convergence solutions on the corresponding behaviour of a re-entrant cell, such as in polymeric auxetic materials
Regarding DOF, CPU time, and number of elements, the results show that the second-order P-method was the most efficient solution for a re-entrant cell subjected to axial loading

Summary

Introduction

Modern technology requires new physical material properties. Study of the material using negative Poisson’s ratio (NPR) is taken into account as an option for material property enhancement [1].Utilizing re-entrant structures with NPR provides the ability to improve mechanical properties in different applications such as medical, automotive, textile engineering etc. [2,3]. Modern technology requires new physical material properties. Study of the material using negative Poisson’s ratio (NPR) is taken into account as an option for material property enhancement [1]. Utilizing re-entrant structures with NPR provides the ability to improve mechanical properties in different applications such as medical, automotive, textile engineering etc. Changing the Polymers 2020, 12, 1312; doi:10.3390/polym12061312 www.mdpi.com/journal/polymers. Polymers 2020, 12, 1312 chemical properties and cell shape are two methods for improving mechanical behaviour [4,5]. Most of the researches in this area focus on changing the chemical elements [6,7,8]. An attempt is being made to enhance the mechanical properties by changing the cell shape of the auxetic structures

Methods

Results

Conclusion