Evaluation of nonlinear elastic behaviors of skin.
Skin Res Technol 2005 Nov; 11(4):287-288
Hendricks et al. have recently published a paper investigating the elastic properties of human skin in vivo via the optical coherence tomography. In their studies, the elastic properties of skins in forearms of 13 subjects have been determined. Hendriks et al. fitted the elastic behaviors of the skin using a Mooney model, which is governed by a strain energy density function: W = C10(I1 - 3) + C11(I1 - 3)(I2 - 3). Assuming small deformation and incompressible material properties, Hendriks et al. obtained an initial elastic modulus, E = 6C10. They found that the elastic modulus of their samples was around 0.069 MPa, which is much smaller than those reported by Barel et al. (0.13-0.26MPa). They attributed this huge difference to omitting the effects of C11, and suggested that these parameters were not directly comparable. Although we agree with Hendriks et al. that the elastic material behavior can be more appropriately simulated using a nonlinear model than using a linearly elastic model, we feel it is not an appropriate approach to evaluate the elastic stiffness of skin by comparing the material parameters of different models. We believe that the elastic deformation behaviors of the skin defined using different models should be compared by evaluating their stress/strain relationships, rather than merely comparing the material parameters.
Skin; Skin-tests; Humans; Models; Analytical-processes
John Z. Wu, NIOSH/CDC, 1095 Willowdale Road, MS-2027, Morgantown, WV 26505, USA
Disease and Injury: Musculoskeletal Disorders of the Upper Extremities
Skin Research and Technology