松质骨粘弹性的数值分析

Numerical Analysis on the Viscoelastic Characteristic of Cancellous Bone

引入基于连续介质力学框架基础之上的现代两相多孔介质模型来描述松质骨的力学行为 ,对松质骨在给定恒应力和变形下的蠕变和应力松弛等与时间相关的粘弹性行为进行了研究。采用Laplace变换技术 ,得到了松质骨蠕变和应力松弛的解析结果。研究表明 ,由于松质骨中流体组分的扩散和流动 。

A one dimensional creep and stress relaxation response of cancellous bone to instant loading is investigated based on the studies with scanning microscope, can cancellous bone be viewed as a cellar solid consisting of an interconnected skeleton filled with medulla. A two phase poroelastic model is introduced to describe the cancellous bone, in which the tissue(material) densities of the skeleton and medulla are assumed to be unchangeable while the corresponding apparent densities are changeable due to the change of volume fraction. The governing equations are derived for the case of a linear poroelastic solid skeleton saturated with an inviscid medulla. Under the loading, responses of the skeleton stress as well as the medullary pressure are obtained with Laplace transform technique. The computational result shows that the cancellous bone is provided with certain features similar to those appearing in viscoelastic solids, which means the responses do not only depend on time, but furthermore depend on previous loading history. It is worth paying attention to the result that the medullary pressure can be negative. This point is due to the recovery of the skeleton after unloading whereas the medulla is not squeezed out but absorbed into the pores by suction.