Effect of Strain Rate on Compressive Behaviour of Silicone Rubber

Kohei Tateyama,Nagahisa Ogasawara,Hiroyuki Yamada,E Buzaud,H Couque,E Cadoni,A Cosculluela

doi:10.1051/epjconf/201818302044

Kohei Tateyama, Nagahisa Ogasawara + Show 5 more

Open Access

https://doi.org/10.1051/epjconf/201818302044

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Abstract

The purpose of this study is to evaluate the effect of strain rate on compressive behaviour of silicone rubber. The silicone rubber which was used as biomimetic material was prepared as a specimen. The shape of specimen was cubic and each side length was 10 mm. In this study, a dynamic compressive test was performed using a drop-weight testing machine at the strain rate of approximately 101 s-1, which can be detect the compressive stress for a long time without any disturbance. For comparison, a quasi-static compressive test was performed using the universal testing machine at the strain rate of 10-4 to 10-1 s-1. In the deformation process of the silicone rubber, the flow stress did not increase at the early stage of deformation. When the strain reached 0.6, the flow stress was increased with increasing strain. This deformation process was considered to be due to rubber elasticity. It was confirmed that the silicone rubber showed an increase of the flow stress with increasing strain rate, which showed general behaviour of soft materials such as rubber. In the silicone rubber, the flow stress with respect to the strain rate could be simply expressed with the Cowper-Symonds constitutive equation.

Highlights

Helmets and protectors are often used to protect the human body from impact loading such as collision of flying objects
This deformation process was considered to be due to rubber elasticity, which occurs when the network structure of the polymer chain at room temperature is in the rubber state [6]
The flow stress with respect to the strain rate could be expressed with the Cowper-Symonds constitutive equation

Summary

Introduction

Helmets and protectors are often used to protect the human body from impact loading such as collision of flying objects. The protective performance has been evaluated by the degree of dent at the clay [1]. When an impact load is applied to the human body protected by the protector, the muscle and the visceral tissues are sometimes damaged by the propagation of stress waves or shock waves, even if the visible scars do not appear [2]. Such damages are called "blunt trauma" and it is difficult to evaluate by the previous testing methods using clay. A method that can evaluate the blunt trauma is required

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