The uniaxial stress versus strain response of pig （猪的单轴应力和应变响应）.pdf

ARTICLE IN PRESS International Journal of Impact Engineering 32 (2006) 1384–1402 /locate/ijimpeng The uniaxial stress versus strain response of pig skin and silicone rubber at low and high strain rates Oliver A. Shergold, Norman A. Fleck, Darren Radford Cambridge University Engineering Dept., Trumpington St., Cambridge, CB2 1PZ, UK Received 22 July 2004; received in revised form 28 November 2004; accepted 30 November 2004 Available online 19 March 2005 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 s1). 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 s1. 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 ru