Experimental and numerical studies on the effect of elongation rate and temperature on the mechanical behaviour of high strength NBR

ABSTRACT

This paper presents rate dependent uniaxial tensile behaviour and relaxation response of high strength acrylonitrile butadiene rubber (NBR) with moderate carbon black content. The rate dependent uniaxial tensile response is investigated for large deformations over moderate range of elongation rates (50–500 mm min⁻¹). Effects of elongation rate on the overall deformation behaviour in terms of stress–strain response, total elongation at break as well as on the breaking stress of the material are investigated. Experimental results revealed that the material behaviour, including elongation at break and breaking stress, is rate dependent. Relaxation behaviour over a temperature range of 30–90 ${}^{\circ }$C, investigated using uniaxial compression experiments, shows drop of stress over the duration of the tests. Additionally, a generic rate dependent hyperviscoelastic model to predict the rate dependent response of the material and simulations of the relaxation tests are presented. Single-step stress relaxation tests from an inbuilt experimental setup and tensile response obtained from test conducted at 200 mm/min elongation rate were used in calibration. The numerical results obtained are seen to be in good agreement with the experimental observations for the range of deformation rate and temperature considered in the uniaxial tensile and relaxation tests, respectively.

KEYWORDS:

• NBR
• viscoelastic material
• elongation rate
• hyperviscoelastic modelling
• breaking stress
• stress relaxation

Disclosure statement

No potential conflict of interest was reported by the authors.