Mechanical Properties Of Human Stomach Tissue

The stomach is a main organ for human body to store and digest food,but the tumor lesions(gastric cancer)of the stomach tissues has been one of the most harmful diseases for Chinese people.It is very useful to understanding the mechanical properties of human gastric tissue for diagnosis and treatment of stomach-related diseases and the optimal design on medical devices.However,there are few studies on the mechanical properties of gastric tissues.Especially,there is a lack of data on the mechanical properties of human gastric tissues.This situation greatly hinders the in-depth understanding of stomach-related diseases and the development of related medical devices.In this thesis,the mechanical properties of human gastric tissue are experimentally studied in details.At the same time,the mechanical behavior of surgical clamps is numerically simulated based on the measured data.Using MTS static universal testing system and digital strain measurement system,the mechanical properties of human gastric tissue,mucosa-submucosa and muscular-serous membrane layer were obtained through uniaxial stretching.The changes of the mechanical properties(elastic modulus,tensile strength,and destructive strain)of the muscular-serosal layer of male samples in three age ranges(50-59,60-69,70-79)were analyzed.The mechanical properties of gastric mucosa-submucosa tissue was further investigated by consideration of the effects of the gender.Then the compressive true stress-strain data of the human gastric tissue mucosa-submucosa and muscular-serous membrane layer were also measured.The compressive performances between different samples were analyzed and discussed.Based on the above data,five commonly used hyperelastic models were employed to fit the experimental data,and then the different hyperelastic constitutive models of the gastric tissue were obtained.Results show that all the five hyperelastic models can describe the experimental data well.Consequently,the constitutive models provided in the present work can be directly used for relevant numerical simulation.In addition,the differences of fitting parameters between the five models with respect to the gastric tissue were analyzed.Finally,based on the hyperelastic constitutive model of human stomach tissue obtained in this work,the mechanical behavior of gastric tissue interacting with different surgical clamps was numerically studied based on FEM analysis software,Abaqus.The influences of size and shape of the clamps,with or without a window,champing force,etcl,are extensively studied.