MODELING OF URINARY BLADDER DEFORMATION WITHIN PASSIVE AND ACTIVE REGIMES

Finite element model for urinary bladder mechanical response during passive filling and muscle activation is presented in the paper. The nonlinear elastic model for the tissue is used according to the Fung potential for the strain energy. Filling of the bladder is simulated by the pressure increase with the passive state of muscles. When the filling phase is completed, muscles are activated with the tripled pressure increase. This modeling is in accordance with the real physiological processes. Data are used from experiments on the rabbit urinary bladder. The computed distribution of stresses reveals non-uniform increase of stresses within muscle fibers during activation.