title: Bladder tissue biomechanical behavior: Experimental tests and constitutive formulation.
abstract: A procedure for the constitutive analysis of bladder tissues mechanical behavior is provided, by using a coupled experimental and computational approach. The first step pertains to the design and development of mechanical tests on specimens from porcine bladders. The bladders have been harvested, and the specimens have been subjected to uniaxial cyclic tests at different strain rates along preferential directions, considering the distribution of tissue fibrous components. Experimental results showed the anisotropic, non-linear and time-dependent stress-strain behavior, due to tissue conformation with fibers distributed along preferential directions and their interaction phenomena with ground substance. In detail, experimental data showed a greater tissue stiffness along transversal direction. Viscous behavior was assessed by strain rate dependence of stress-strain curves and hysteretic phenomena. The second step pertains the development of a specific fiber-reinforced visco-hyperelastic constitutive model, in the light of bladder tissues structural conformation and experimental results. Constitutive parameters have been identified by minimizing the discrepancy between model and experimental data. The agreement between experimental and model results represent a term for evaluating the reliability of the constitutive models by means of the proposed operational procedure.
authors.affiliation: Centre for Mechanics of Biological Materials, University of Padova, Via F. Marzolo 9, I-35131 Padova, Italy; Department of Industrial Engineering, University of Padova, Via F. Marzolo 9, I-35131 Padova, Italy. Electronic address: arturo.natali@unipd.it.
authors.forename: A N
authors.initials: AN
authors.lastname: Natali
authors.affiliation: Department of Mechanical and Aerospatial Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy.
authors.forename: A L
authors.initials: AL
authors.lastname: Audenino
authors.affiliation: University of Verona, Department of Urology, Policlinico G.B. Rossi, Ospedale Borgo Roma, P.le L.A. Scuro 10, 37134 Verona, Italy.
authors.forename: W
authors.initials: W
authors.lastname: Artibani
authors.affiliation: Centre for Mechanics of Biological Materials, University of Padova, Via F. Marzolo 9, I-35131 Padova, Italy.
authors.forename: C G
authors.initials: CG
authors.lastname: Fontanella
authors.affiliation: Centre for Mechanics of Biological Materials, University of Padova, Via F. Marzolo 9, I-35131 Padova, Italy; Department of Industrial Engineering, University of Padova, Via F. Marzolo 9, I-35131 Padova, Italy.
authors.forename: E L
authors.initials: EL
authors.lastname: Carniel
authors.affiliation: Department of Engineering, University of Perugia, Via Duranti 65, 06125 Perugia, Italy.
authors.forename: E M
authors.initials: EM
authors.lastname: Zanetti
mesh_terms: D000818:Animals; D016880:Anisotropy; D001696:Biomechanical Phenomena; D001703:Biophysics; D008422:Materials Testing; D055595:Mechanical Phenomena; D015203:Reproducibility of Results; D013314:Stress, Mechanical; D013552:Swine; D001743:Urinary Bladder / Q000166:cytology*; D014783:Viscosity
keywords: Bladder; Computational approach; Experimental test; Non-linear mechanics; Soft tissue mechanics