title: Analysis of the structural behaviour of colonic segments by inflation tests: Experimental activity and physio-mechanical model.
abstract: A coupled experimental and computational approach is provided for the identification of the structural behaviour of gastrointestinal regions, accounting for both elastic and visco-elastic properties. The developed procedure is applied to characterize the mechanics of gastrointestinal samples from pig colons. Experimental data about the structural behaviour of colonic segments are provided by inflation tests. Different inflation processes are performed according to progressively increasing top pressure conditions. Each inflation test consists of an air in-flow, according to an almost constant increasing pressure rate, such as 3.5 mmHg/s, up to a prescribed top pressure, which is held constant for about 300 s to allow the development of creep phenomena. Different tests are interspersed by 600 s of rest to allow the recovery of the tissues' mechanical condition. Data from structural tests are post-processed by a physio-mechanical model in order to identify the mechanical parameters that interpret both the non-linear elastic behaviour of the sample, as the instantaneous pressure-stretch trend, and the time-dependent response, as the stretch increase during the creep processes. The parameters are identified by minimizing the discrepancy between experimental and model results. Different sets of parameters are evaluated for different specimens from different pigs. A statistical analysis is performed to evaluate the distribution of the parameters and to assess the reliability of the experimental and computational activities.
authors.affiliation: Department of Industrial Engineering, Centre for Mechanics of Biological Materials, University of Padova, Padova, Italy emanueleluigi.carniel@unipd.it.
authors.forename: Emanuele L
authors.initials: EL
authors.lastname: Carniel
authors.affiliation: The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy.
authors.forename: Margherita
authors.initials: M
authors.lastname: Mencattelli
authors.affiliation: The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Bonsignori
authors.affiliation: Department of Biomedical Sciences, University of Padova, Padova, Italy.
authors.forename: Chiara G
authors.initials: CG
authors.lastname: Fontanella
authors.affiliation: Department of Industrial Engineering, Centre for Mechanics of Biological Materials, University of Padova, Padova, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Frigo
authors.affiliation: Department of Industrial Engineering, Centre for Mechanics of Biological Materials, University of Padova, Padova, Italy Department of Biomedical Sciences, University of Padova, Padova, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Rubini
authors.affiliation: The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy.
authors.forename: Cesare
authors.initials: C
authors.lastname: Stefanini
authors.affiliation: Department of Industrial Engineering, Centre for Mechanics of Biological Materials, University of Padova, Padova, Italy.
authors.forename: Arturo N
authors.initials: AN
authors.lastname: Natali
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena / Q000502:physiology*; D035843:Biomedical Research / Q000379:methods*; D003106:Colon / Q000502:physiology*; D004548:Elasticity; D008954:Models, Biological; D011312:Pressure; D013552:Swine; D013718:Tensile Strength; D014783:Viscosity
keywords: Gastrointestinal tract; inflation test; mathematical modelling; visco-elasticity