Mechanical Evaluation of Touching Motion on the Skin Surface Elasticity by Indentation

This study aimed to develop a non-invasive technique for skin elasticity assessment and facilitate the prevention, nursing, and treatment of skin tears through an interdisciplinary study of skin-touching deformation behavior. First, to study the elasticity of the skin of the elderly, the skin indentation modulus on the forearms of 28 elderly individuals aged ≥ 75 years was measured. According to the measurements, the identified skin modulus ranges from 2.45-60 kPa. Two-layer skin models were constructed based on the measurements and related references. By analyzing these two models, an estimated model was proposed to assess the elasticity of the upper part of the skin by indentation. In this study, the spherical indentation was considered relevant to finger palpation. Subsequently, the touching deformation behavior of the skin was computationally analyzed using various failure criteria to determine the effective positions of stress indices in the two-layer skin structure. Additionally, the collapse behavior of the skin is discussed for nurses to reduce skin tears, and it is concluded that patients with high skin elasticity should avoid tensile-related treatments, and those with low elasticity should avoid compression-related treatments.