密质骨损伤机理的实验研究

AN EXPERIMENTAL STUDY ON THE DAMAGE MECHANISM OF COMPACT BONE

用Ｉｎｓｔｒｏｎ试验机对新鲜人股骨密质骨试样进行了一维拉伸实验研究，利用实验结果对由平行粘弹性杆系统建立的密质骨损伤本构模型待定参数进行拟合，获得了较高的相关系数（Ｒ≥０．９０）和较好的显著性水平（α≤０．０１）。此外，对拉伸试样破坏断面进行扫描电镜（ＳＥＭ）观察和分析。实验发现，在准静态加载情形下，微裂纹沿着粘合线扩展，骨单位被从骨组织中拔出，并呈粘性特征。

Tests in tension at strain rates from 4.0 ×10￣-5/s to 9.0×10￣-3/s are performed on wet human compact bone specimens by the Instron Testing Instrument. The unknown parameters in the damage model based on the parallel viscoelastic bar system are determined by experimental data and the higher correlation coefficient (R≥0.90) is obtained. The fracture surfaces of the specimens are observed and analyzed by scanning electron microscope. The results indicate that, under the quasi-static loading condition, microfractures propagate through cement lines and Haversian osteons are pulled out of bone matrix, just as a creep move. This shows that the damage mode of the sequential pull-out of the osteons from bone matrix is reasonable.