粘弹性对SMP正畸弓丝弹性回复力的影响研究

发布时间：2018-05-12 03:18

  本文选题：正畸弓丝 + 形状记忆聚合物　； 参考：《浙江工业大学》2014年硕士论文

【摘要】：口腔正畸中,固定矫治器常用的金属镍钛弓丝会释放镍离子,可能引起过敏,同时矫治力释放较快。针对这一问题,提出一种聚氨酯形状记忆聚合物弓丝。形状记忆聚合物(SMP, Shape memory polymer)材料与形状记忆合金(SMA, Shape memory Alloy)材料相比具有很多优点：耐腐蚀、形变量大、无色、良好的生物相容性,以及形状记忆恢复温度可在很大范围内调节。另外该材料容易成型,很方便通过注射、挤压、涂覆等方法成型得到所需要的特殊形状。本文主要采用实验和仿真相结合的方法,研究SMP粘弹性对其正畸弓丝弹性回复力影响,探究其初步应用于正畸矫正弓丝的可行性,所做的工作主要如下：首先通过挤出成型的方法加工出聚合物弓丝,然后进行拉伸实验,并对应力-应变曲线进行拟合,得到该弓丝不同温度下的弹性模量和粘性系数,构建材料参数与温度之间的关系。在此基础上,将现有SMP只能描述简单受力状态的一维热力学本构方程,拓展到三维形式,基于ABAQUS的二次开发功能,对聚合物弓丝进行拉伸形变,并对聚合物弓丝完整的形状记忆过程和形状记忆性能进行了仿真分析。结果表明：在不同的应变条件下,形状固定率接近80%；加热过程中应变完全回复；弓丝应力随着温度的升高而减小,具有良好的形状记忆性能,直径为0.5mm弓丝回复力的大小在65g-120g范围内。然后,通过实验和仿真的方法研究了SMP粘弹性对其正畸弓丝弹性回复力的影响并对结果进行了分析。通过分析正畸弓丝在口腔中的约束并进行简化,对聚合物弓丝进行了三点弯曲实验、简支梁和悬臂梁实验；为探究其缓慢释放正畸力的性能进行了应力松弛实验；并在typodont正畸模拟牙颌架上进行了正畸效果的验证。结果表明：由于聚合物弓丝具有粘弹性,在简支梁和悬臂梁实验中,发现只有在小变形范围内,聚氨酯SMP弓丝的挠度变形曲线符合标准弹性杆的挠度方程；通过三点弯曲实验得到的加载和卸载应力-应变曲线,发现由于粘弹性作用,聚氨酯SMP弓丝弹性回复力能够缓慢释放具有力学稳定性;而应力松弛实验则反映了在粘弹性作用下,聚氨酯SMP弓丝具有良好的缓慢释放正畸力的性能；在typodont模型上正畸验证实验结果也比较理想。因此,聚氨酯SMP弓丝具有应用于正畸矫治的前景。
[Abstract]:In this paper , the effect of elastic restoring force on the orthodontic arch wire is studied by means of extrusion molding , and the relationship between the elastic modulus and the temperature of the shape memory alloy is studied .
the strain is fully recovered during the heating process ;
The effects of SMP viscoelasticity on the elastic restoring force of orthodontic archwire in the range of 65 g - 120 g were studied by means of experiments and simulation .
The stress relaxation experiment was carried out to investigate the performance of slow release of orthodontic force .
The results show that the deflection deformation curve of the polyurethane SMP arch wire conforms to the deflection equation of the standard elastic rod only in the small deformation range due to the viscoelasticity of the polymer arch wire .
Through three - point bending experiment , the stress - strain curve is loaded and unloaded , and it is found that the elastic restoring force of the polyurethane SMP arch wire can release the mechanical stability slowly due to the viscoelastic effect , and the stress relaxation experiment shows that the polyurethane SMP arch wire has good properties of slowly releasing the orthodontic force under the action of viscoelasticity ;
The results of the orthodontic verification experiment are also ideal in the orthodontic treatment model . Therefore , the polyurethane SMP arch wire has the prospect of being applied to orthodontic treatment .

【学位授予单位】：浙江工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R783.5
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本文编号：1876885