加载速率对大鼠股骨3点弯曲实验的影响

目的:探讨在大鼠股骨标本的3点弯曲实验中,加载速率变化对实验结果的影响. 方法:选取32个雄性SD大鼠股骨标本,以常选用的加载速率范围内的1、3、5 mm/min和较大值的20 mm/min分4组进行3点弯曲实验,观察各标本最大载荷、弹性载荷、最大桡度、弹性桡度、最大应力、弹性应力、最大应变、弹性应变、弹性模量等9项骨生物力学指标的变化情况. 结果: 以1、3、5 mm/min速率加载时,速度越快,大鼠股骨标本9项指标越高,但差异无显著性(P＞0.05);而以20 mm/min的速率加载时,与1、3、5 mm/min速率加载相比较, 9项指标均显著增加(P＜0.05). 结论: 在大鼠股骨3点弯曲实验中,常选用的加载速率范围内(1～5 mm/min)变化时, 对骨的结构力学和材料力学指标无显著改变.而当加载速率超过一定范围时,对骨的结构力学和材料力学指标可产生显著影响.

Effects of Loading Speeds on Three-point Bending Experiments Using Rat Femoral Samples

Objective:To investigate the effects of varied loading speeds in three-point bending experiments using rat femoral samples.Methods: 32 femoral samples of SD male rats were selected and studied under varied loading speeds(1mm/min,3mm/min,5mm/min,20mm/min),to observe the changes of their ultimate load,elastic load,ultimate deformation and elastic deformation,ultimate stress and elastic stress,ultimate strain and elastic strain,elastic modul.Results: At 1mm/min,3mm/min and 5mm/min loading speeds,all of the data increased gradually but not significantly(P>0.05);in contrast,at 20 mm/min loading speeds,the data increased significantly(P<0.05).Conclusion: In three-point bending experiments of rat femoral samples,loading speeds within common range(1-5 mm/min) had no effects on structural and material properties,but when increased considerably beyond this,may change the structural and material properties significantly.