A Constitutive Model for Softening Behaviors of Skin Tissue

Skin tissue is a kind of complex biological material abundant with fibers. A new constitutive model, relating macroscopic responses with microstructural fiber configuration alteration, is developed to investigate the stress softening behaviors of skin tissue observed during cyclic loading–unloading tests. Two influential factors are introduced to describe the impact of fiber configuration change and stretch-induced damage. The present model achieves good agreement between predicted stress distribution of human skin and corresponding ex vivo experimental data obtained from the literature, affirming its capability to effectively capture the characteristic softening behaviors of human skin under cyclic loading conditions.