Study On Mechanic Properties Of Rabbit's Stomach Wall And Its Whole Response Under Loads

In recent years, with social development, the variety of the public esthetic sense, patients of the gastroptosis presents younger and its occupation scope also expands gradually. Stomach lies in the left-top abdomen cavity. Its position keeps fixed relatively owing to two factors which is circumferential ligaments in stomach and a certain tension of stomach wall, so it can maintains daily function When the factors change, because of gravity gastroptosis happens. Gastroptosis is a common chronic disease and patient suffers pain hardly when its occurrence. The Chinese medicine treatment having many methods, orally or external application Chinese herbal medicine, puncture and massage, in addition to physical training and using the stomach supporter can repress its development. The quickly treatment way is a surgical operation, it reserves pneumogastric nerves and cuts off stomach body and suspends stomach bottom where stomach is fixed to the liver through original ligaments of liver. This text studied the mechanics principle of that surgical operation.In this paper , the forces on the rabbit's stomach wall were simplified based on analyzing the anatomy structure of the stomach. And then we made a model in vitro for simulating the development of gastroptosis.With INSTRON5544 tension meter, uniaxial tension, creep, relaxation and ultimate stress tests were performed on the specimens of muscle strips of rabbit's stomach wall in biotic environmental box which was built to simulate the environment of human body. The elastic modulus and strength were measured for normal stomach and gastroptosis. The results indicate that along greater curvature of the stomach elastic modulus of the longitudinal strips is bigger than transverse and gastroptosis is smaller than normal.A viscoelastic constitutive equation with three parameters was proposed to describe the mechanical properties of the specimens.We built a finite element model for analyzing the mechanical behavior of a stomach in vivo. The calculating results shown that the displacement and the stress in small curvature of the stomach wall after 3 Newton was similar to the displacement of the previous model in vitro.The sections of the normal stomach wall and the gastroptosis were inspected. No distinct biological difference was found, but it is helpful to study the gastroptosis further.