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  • Publication
    Characterization of the anisotropic mechanical properties of excised human skin
    The mechanical properties of skin are important for a number of applications including surgery, dermatology, impact biomechanics and forensic science. In this study, we have investigated the influence of location and orientation on the deformation characteristics of 56 samples of excised human skin. Uniaxial tensile tests were carried out at a strain rate of 0.012 s−1 on skin from the back. Digital Image Correlation was used for 2D strain measurement and a histological examination of the dermis was also performed. The mean ultimate tensile strength (UTS) was 21.6±8.4 MPa, the mean failure strain 54%±17%, the mean initial slope 1.18±0.88 MPa, the mean elastic modulus 83.3±34.9 MPa and the mean strain energy was 3.6±1.6 MJ/m3. A multivariate analysis of variance has shown that these mechanical properties of skin are dependent upon the orientation of the Langer lines (P<0.0001−P=0.046). The location of specimens on the back was also found to have a significant effect on the UTS (P=0.0002), the elastic modulus (P=0.001) and the strain energy (P=0.0052). The histological investigation concluded that there is a definite correlation between the orientation of the Langer lines and the preferred orientation of collagen fibres in the dermis (P<0.001). The data obtained in this study will provide essential information for those wishing to model the skin using a structural constitutive model.
    Scopus© Citations 518  446
  • Publication
    Dynamic Tensile Properties of Human Skin
    (International Research Council on the Biomechanics of Injury, 2012) ; ; ;
    The mechanical properties of skin are important for a number of applications including surgery, dermatology, impact biomechanics and forensic science. Studies have shown that the anisotropic effects of skin have been linked to sample orientation with respect to contour lines of tension, i.e. the Langer’s lines. There have been numerous studies undertaken to calculate the influence of Langer’s lines on the mechanical properties of human skin at quasistatic strain rates; however, it is relatively unknown what occurs at dynamic speeds. This study conducts a number of dynamic mechanical tensile tests to investigate the influence dynamic speeds have on the mechanical properties of human skin. The testing protocol involves uniaxial tensile tests at three different dynamic speeds, 1m/s, 1.5m/s and 2m/s, performed using an Instron tensile test machine. A total of 33 tests were conducted on 3 human cadavers aged 85, 77 and 82. Samples were excised at specific locations and orientations with respect to the Langer’s lines. The purpose for this was to recognise the significance that location and orientation have on the mechanical properties of human skin. The mean ultimate tensile strength (UTS) was 27.2±9.3MPa, the mean strain energy was 4.9±1.5MJ/m3, the mean elastic modulus was 98.97±97MPa and the mean failure strain was 25.45±5.07%. This new material data for human skin can be applied to constitutive models in areas such as impact biomechanics, forensic science and computer‐assisted surgery.
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