Research On Mechanical Properties Of Pig Skins As Biological Materials

The impact in traffic accidents, the stampede in sports and the explosion shock in the military operations are all going to bring great harm to the human body; it is also likely to cause fatal damage to our lives. As a kind of main body tissues and organs, skin tissue coves our body and prevents us from external impact. Mostly, in a collision accident, the first to be hit is skin tissue. For this reason, to study the dynamic mechanics performance of skin tissue under high-speed impact can provide not only certain references for different types of personal injury evaluation and design for protective devices, but also some important theoretical basis for finding a substitute for biological tissues.Compared to traditional metal materials in engineering, testing the performance of biological tissue becomes comparatively difficult because of its attribute of life and the softer physical characteristics. Specific to the situation that mentioned above, a feasible and effective method of sample preparation and preservation has been put forward in this paper, it is to make the specimens in the form of regular cylindrical and remain the pig skin sample active as much as possible.Once the program of sample preparation and sample preservation was determined, the quasistatic experiment of skin tissue would be conducted. The low strain rate experiment is usually divided into two parts, the first part in compression test of skin tissue the low strain rate: the value of compression strain is fixed, its stress-strain relation is obtained in different loading rates that made comparative analysis; Second, it is experiment of compression relaxation which study compression relaxation effect under different loading rates and strain value. The results of the quasi-static compression test would be analyzed with compression relaxation experiments, exploring the intrinsic relationship between them, and some preliminary explanations are made to the phenomenon of their presence.On the basis of the existing Split Hopkinson Pressure Bar(SHPB) experimental technology, this paper has made some exploratory study on the dynamic mechanical properties of soft tissue in skin under high strain rates, and obtained numerous data of dynamic compression test, then compared them with the data in the low strain rate experiment; finally, it found that the skin material has significant strain rate effect under a wide range of strain rates. Furthermore, we made possible explanation for strain rate effect and the bulge of stress-strain curve in SHPB test, which may be caused by dehydration circumstances of skin tissue; finally we have put forward the skin tissue compression model that related to the dehydration skin tissue.On the basis of previous studies, this paper has made some improvement on the model of soft skin tissue. Soft skin tissue have been studied by a lot of the literature in constitutive model that adopt the hyperelastic model which describe the rubber material or the viscoelastic model which describe viscoelastic materials. Hyperelastic model is combined with viscoelastic model to create a sticky-hyperelastic model which was fitted to the experimental data analysis, finally biomechanical model parameters of the skin material is got. When selecting hyperelastic mode, with a variety of hyperelastic model fitting to the experimental data, finally Mooney hyperelastic model is choosed because of the high fitting degree, and ultimately determine the method Mooney model in parallel with Maxwell model are determined, as well as the skin constitutive model class of biomaterials is built.