| Bone,as one kind of extreme singular complex material,its mechanical character has caused widespread interests,especially the compact bone,which started long time before.The compact bone is a kind of composite material and from the point that nearly all kinds of biological solid are viscoelastic,we consider bones to be a kind of viscoelastic and anisotropical composite material.In the commonly used term of solid mechanics,this kind of adhesive material called matrix.For the reason above,we take fiber reinforced material theory to carry out creep analysis.Based on the analysis to macroscopic structure and microscopic structure of the bone and the structure character of the viscoelastic material,we studied the mechanic character of the compact bone,made a analysis of the viscoelastic and anisotropical character of human shaft compact bone,and consider it to be a transverse isotropy material,and put forward a cylindrical shell mechanical model of viscoelastic complex material of cattle shinbone.In our study,we considered the biotic shinbone to be a kind of cylindrical shell of complex material which had viscous properties,and according to the joint character of the shinbone,we simplified the boundary conditions to be two-side simply supported boundary conditions,and the creep buckling control equation of viscoelastic cylindrical shell that was under axially load was given.Based on laplace-transform,the control equation was transformed in phase space,in which we obtained the critical load expression formula.Followed by inverse laplace-transform, the time-dependent creep load curve was obtained.Finally,according to the specific viscosity coefficient of human shinbone,we calculated and made a analysis to the axial compression buckling pressure,and obtained creep buckling critical load curve,figured the variation curve of creep buckling load to the length of the shinbone and the time,and found out that the buckling pressure increased as the length of the shinbone deceased.. |
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