Article,
The uniaxial stress versus strain response of pig skin and silicone rubber at low and high strain rates
International Journal of Impact Engineering, 32 (9): 1384--1402 (September 2006)
Abstract
The uniaxial compressive responses of silicone rubber (B452 and Sil8800)
and pig skin have been measured over a wide range of strain rates
(0.004-4000�s-1). The uniaxial tensile response of the silicone rubbers
was also measured at low strain rates. The high strain rate compression
tests were performed using a split-Hopkinson pressure bar made from
AZM magnesium alloy. High gain semi-conductor strain gauges were
used to detect the low levels of stress (1-10�MPa), and a pulse shaper
increased the rise time of dynamic loading on the specimen. The experiments
reveal that pig skin strain hardens more rapidly than silicone rubbers
and has a greater strain rate sensitivity: pig skin stiffens and
strengthens with increasing strain rate over the full range explored,
whereas silicone rubber stiffens and strengthens at strain rates
in excess of 40�s-1. A one term Ogden strain energy density function
adequately describes the measured constitutive response of each solid,
and a strategy is outlined for determining the associated material
constants (strain hardening exponent and a shear modulus). The strain
rate sensitivities of the pig skin and two silicone rubbers are each
quantified by an increase in the shear modulus with increasing strain
rate, with no attendant change in the strain hardening exponent.
It is shown that the Mooney-Rivlin model is unable to describe the
strong strain hardening capacity of these rubber-like solids.
