This is a study to evaluate the biomechanical properties of porcine trachea; the intention is to provide experimental methods as well as evidence for further studies on human trachea and artificial trachea. In the current study, the biomechanical indices such as bending stiffness, radial pedestal and stress-straining, bursting strength, and residual stress were adopted. The findings were as follows: there is residual stress in the trachea; when the 50mm trachea is compressed 50%, the force of radial pedestal is about 10N; the force of break from cricoid to eminence is from 180mmHg to 110mmHg. Meanwhile, the data of bent are gained and the curve of stress-straining is depicted. Rresidual stress exists in porcine trachea, and trachea membrane disrupts with the increasing of endotracheal pressure; meanwhile, the porcine trachea possesses fine properties such as radial pedestal, bending and elongation.
Animals ; Biomechanical Phenomena ; Elasticity ; Female ; Male ; Pressure ; Stress, Mechanical ; Swine ; Tensile Strength ; Trachea ; physiology

A hydrostatic compression device has been designed to study the effects of intermittent or continuous compressive forces on cells by trying to mimic in vivo forces. The model system is composed of two pistons that deliver and release compressed air under control of a motor to form an enclosed tissue culture chamber housing numerous tissues culture dishes. The continuous compressive forces and intermittent compressive forces are within 100-300 KPa and 0-30 KPa respectively. The compressive force is uniform in the system and can also result in the generation of shear forces along the interface between the cells and culture substratum, so the hydrostatic compression device can be used to study the characteristics of in vitro cells loading models.
Biomechanical Phenomena ; Cell Culture Techniques ; instrumentation ; methods ; Compressive Strength ; Computer-Aided Design ; Equipment Design ; Humans ; Shear Strength ; Stress, Mechanical

A biphasic porous medium model based on the mixture theory in continuum mechanics frame was used to depict the distributions of osseous stress field, distortion field and pore pressure when the bone tissue was subject to various dynamic loads. In the model, the bone tissue was considered as a transversely isotropic, liquid saturated porous material. The coupling relationship among the distortion, fluid flow and the streaming potential is studied. The Galerkin weighted residual method was used to derive the finite element formulation for dynamic response and the streaming potential calculating formulation of bone tissue, the penalty finite element formulation was obtained via introducing the ratio term of pressure p and penalty parameter beta in the continuity equation and, in turn, eliminated the pressure term in governing equation sets. The computational results show that the viscoelastic behavior and the energy dissipation property in the bone tissue, especially in the cancellous bone, is caused to a great extent by the pore liquid flow and diffusion. Meanwhile, because of the existence of electrical double layer between the solid phase and liquid phase, when the liquid constituents in the pore diffuse, the streaming potential appears, and the growth and absorption of bone tissue is expedited.
Biomechanical Phenomena ; Biophysical Phenomena ; Biophysics ; Bone and Bones ; physiology ; Elasticity ; Electrophysiology ; Finite Element Analysis ; Humans ; Models, Biological ; Porosity ; Stress, Mechanical ; Viscosity

There has been a lot of controversies on which layer the silastic implants should be inserted in the augmentation rhinoplasty, i.e. subperiosteal or deep subfascial. This study is to investigate the biomechanical properties of human nasal periosteum and deep fascia, including tensile strength, stress-strain and stress relaxation characters under uniaxial tension system. The periosteum is stronger in tensile strength than that of the fascia, but it is less elastic. Under a sudden increase of load, the periosteum relaxes far less than the fasia. Therefore, in view of biomechanics, the periosteum is thicker, tougher, stiffer and less relaxation than facia, thus has a better fixation effect.
Biomechanical Phenomena ; Elasticity ; Fascia ; physiology ; Humans ; Nose ; anatomy & histology ; Periosteum ; physiology ; Stress, Mechanical ; Tensile Strength

To investigate the biomechanical behavior of human intestines. The tensile test human intestine was performed with the electronic tension machine in this paper. The results indicate that the exponential relationship for the stress-strain of the human intestine was obtained, and the exponential coefficient a of each segment of the intestine is almost the same although the constant C is different. It also shows that the relative rate of stretch length of each segment intestines is different in longitudinal and circumferential directions. And the incremental elastic modulus of colon is less than those of small intestine. It is considered that the colon can be more easily deformed. The experimental results provide the theoretic basis for research on intestinal endoscopic microrobot.
Biomechanical Phenomena ; Colon, Transverse ; physiology ; Elasticity ; Humans ; In Vitro Techniques ; Intestine, Small ; physiology ; Stress, Mechanical ; Tensile Strength

The biomechanical properties of eight human corneas from four normal Chinese fresh corpses were investigated by use of one dimension tensile test, tensile stress relaxation and creep test. The destructive load, stretchy ratio, spreading stress, spreading strain and elastic modulus were determined. Also obtained were the stress relaxation and creep data and curves. After reduction of data, the reduced stress relaxation and creep data and curves were worked out. The regression method was used to get the regression coefficient. The least square method was employed to fit the data of stress and strain; then the stress-strain formula was expressed and the curves of human cornea were plotted. The constitutive equation is K (lambda,t) = G(t) T(e) (lambda) and some conclusions are drawn.
Biomechanical Phenomena ; Cornea ; physiology ; Elastic Modulus ; Humans ; Stress, Mechanical

The purpose of this study was to investigate the effect of different backpack load on the plantar pressure of people during walking. By using three-dimensional force platform system, we collected the ground reaction force data from 20 college students, who were carrying different loads on their backs, and then we transformed the data into a characteristic two-peak curve. Seven characteristic parameters on the curve were selected and analyzed by using statistical methods. The results indicated that the peak ground reaction forces increased as the loads increased. Furthermore, in consideration of different genders, the amount increased was different. For the male subjects, when backpack load reached 17% body weight, changes in ground reaction force began to take place until the backloads reached 20% body weight changes in ground reaction force induced a significant difference. Por the female subjects, changes in ground reaction force began to take place with loads up to 14% body weight and while it reached 15% body weight it induced a significant difference.
Back ; physiology ; Biomechanical Phenomena ; physiology ; Female ; Foot ; physiology ; Humans ; Male ; Pressure ; Stress, Mechanical ; Walking ; physiology ; Weight-Bearing ; physiology ; Young Adult

Biomechanical Phenomena ; Humans ; Skin Physiological Phenomena ; Skin, Artificial ; Stress, Mechanical ; Tensile Strength

We tested the mechanical properties of fiber layers in adult anulus fibrosus of lumbar interverbral disc 4,5. Aulus fibrosus of lumbar interverbral disc was delaminated by using microsurgical technique. 8 testing points were taken in each layer according to the fibers going and 5 testing specimens were taken from each testing point. The length was 15-20mm, the width 1-2mm, and the thickness 0. 1-0. 5mm. By using tension test,the relationship curves of stress and strain were tested, the fitting curves and equations were obtained, and then the elastic modulus, damage strain and damage stress were obtained. Therefore we knew the parameters and equations of mechanical properties of each testing point. We got the result that the elastic modulus of each testing point, along the radius from outside to inside, decreased with the increase of layers. The damage stress decreased linearly from outside to inside. The damage strains of the outside 9 layers increased slightly with the increase of layers, and the others were almost constants, i. e. 0.34 +/- 0.14. We get the conclusion that analus fibrosus of intervertebral disc has special mechanical properties corresponding with its functions, which is in a close relationship with lumbar vertebral diseases.
Adult ; Biomechanical Phenomena ; Elasticity ; Humans ; Intervertebral Disc ; physiology ; Lumbar Vertebrae ; physiology ; Male ; Stress, Mechanical ; Tensile Strength ; physiology

A detailed three-dimensional nonlinear finite element model of lumbar segment L3-L5 was developed to investigate the influence of vibration on the components of human spine. The results show that the vibration effects of different spinal components are not exactly the same, and the stress near the posterior region of L4-L5 annulus is higher than that of its anterior region. The vibration exerts a great influence on the facet joint of L4-L5 segment. The changing amplitudes of stress and deformation of spine reduce by 50% on the condition that the damping ratio is 0.08.
Biomechanical Phenomena ; Cadaver ; Computer Simulation ; Finite Element Analysis ; Humans ; Lumbar Vertebrae ; physiology ; Models, Biological ; Nonlinear Dynamics ; Stress, Mechanical ; Vibration ; Weight-Bearing ; physiology