A Structural Continuum Constitutive Model for a Two-Phase Soft Tissue

Due to the complexity in determining multi-constituent tissue properties, most structural constitutive models for soft tissues focus on a single constituent. However, many tissues contain multiple load-bearing constituents, such as collagen fibers and smooth muscle (SM) cells. Moreover, to elucidate how observed changes in tissue components are related to altered net mechanical behavior at the tissue level, structural constitutive models require physiological relevant model parameters and formulations for changes in referential configuration when one component is physically removed. As an excellent example application that underscores these issues, we have examined the urinary bladder wall (UBW), which undergoes large deformations and exhibits highly nonlinear and anisotropic mechanical behavior [1,2]. Moreover, it undergoes profound remodeling in response to different pathologies such as spinal cord injury (SCI) [1,2].