链状橡皮圈应力松弛的研究

目的通过定期测量链状橡皮圈负载后应力的变化，研究它应力松弛的过程及在不同负载下应力松弛率的异同。方法选取链状橡皮圈30个，随机分为3组，每组10个，3组试样分别负载100克、150克和200克。通过定期测量链状橡皮圈在不同负载下的应力了解应力的变化过程。对3组试样的应力变化进行统计分析。结果链状橡皮圈在最初的48小时内应力衰减较快，负载48小时后残余应力为初始应力的87％左右（86．8％～88．6％），之后应力松弛的速率逐渐减小，至第32天时残余应力为初始应力的69．59，6～88．39，6。在负载较小时（100克），链状橡皮圈应力松弛较少。结论应用链状橡皮圈时宜使用轻力，以利于矫治力值的持续与稳定。当负载较大时，则应缩短复诊间隔，防止矫治力出现太大的衰减而影响正畸治疗的效果。

The Stress Relaxation of Elastomeric Chain

Objective By way of measure the stress of elastomeric chain periodically after three different loads were load on,to evaluate the stress relaxation of it,comparing the stress relaxation of the three different loads.Methods The selection elastomeric chain thirty,divide randomly into three groups randomly,each group of ten,every group distinction load 100 grams,150 grams and 200 grams.In the experiment measure the stress of elastomeric chain under different load regularly.Carries on the comparison to different load rate of change and makes the statistical analysis.Results It was discovered elastomeric chain are biggest in the experimental initial 48 hour internal stress weaken,after load 48 hours remaining stress for about initial stress 87%(86.8%~88.6%).After 48 hours their stress relaxation speed reduces gradually,to 32nd day remaining stress for initial stress 69.5%~88.3%.The stress relaxation rate of elastomeric chain is different,initially when the load 100 grams stresses weaken slowly.Conclusion The small the load is,the slightly the elastomeric chain stress weakens.