控制记忆合金丝镍钛根管锉弯曲性能有限元分析模型的构建及力学分析
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摘要
目的:通过三维有限元实验方法建立模型,用来评价控制记忆合金丝(controlled memory,CM)镍钛根管锉的弯曲性能,并将其与其他相同几何形态的镍钛合金进行比较。方法:基于逆向工程技术,将21 mm长、25#/08锥度的Hyflex NT和Hyflex CM镍钛锉通过悬臂弯曲模型在距锉尖9. 5 mm处固定,力学检测仪压头在距锉尖3 mm处加载/卸载力,最大位移3 mm,得到载荷位移曲线,随后使用显微CT扫描(层间距8μm)镍钛锉,导入ABAQUS(6. 10)构建几何模型。Hyflex NT以形状记忆合金本构模型,Hyflex CM以幂硬化塑性本构模型,拟合悬臂弯曲的载荷位移曲线。结果:成功构建两个四面体单元模型,节点总数均为99 353,单元总数均为63 744。当加载位移为1 mm时,对距锉尖6. 1 mm处的横截面进行应力分布观测,上、下表面受到的弯曲应力最大,并率先进入相变屈服阶段,有限元模拟能够清楚地给出锉在变形过程中的变形特点、应力分布等各种信息,与实际实验曲线拟合度好。结论:材料本构行为对于镍钛根管锉力学行为的影响十分显著,针对CM丝镍钛根管锉的特性调试参数而建立的有限元模型能够精确地捕捉镍钛根管锉各种变形过程中的特点,且与实际实验曲线拟合度好,可用于CM丝镍钛锉弯曲性能研究。
Objective: To construct a model for a controlled memory(CM) nickel-titanium(Ni Ti) file and another M-wire Ni Ti file with the same geometry by using finite element analysis. To evaluate the flexibility of a CM Ni Ti file by using three dimensional finite element method and to compare its mechanical responses with that M-wire Ni Ti. Methods: Based on the reverse engineering,the 21 mm long,25#/08 taper Hyflex NT Ni Ti file and Hyflex CM Ni Ti file were fixed by the cantilever bending model at a distance of 9. 5 mm from the tip of the file. The mechanical tester's indenter was loaded/unloaded at a distance of 3 mm from the tip of the file. The maximum displacement was 3 mm,the load displacement curve was obtained. Subsequently,by using a micro-CT to scan(layer spacing of 8 μm) Ni Ti files,and ABAQUS(6. 10) was introduced to construct a geometric model. Hyflex NT was considered as a shapememory alloy constitutive model,Hyflex CM was considered as a power-hardening plastic constitutive model,respectively. Comparing the load-displacement curve of cantilever bending in the three-dimensional finite element model with the load-displacement curve in the experiment. Results: Two tetrahedral element models were constructed,the total number of nodes was 99 353 and the total number of cells was63 744. When the loading displacement was 1 mm,the stress distribution of the cross section at 6. 1 mm from the tip of the file was observed. The upper and lower surfaces were subjected to the maximum bending stress and entered the phase transformation yield stage. The finite element simulation could clearly show the deformation of the file. Various information such as deformation characteristics and stress distribution in the process were well fitted to the actual experimental curve. Conclusion: The constitutive behavior of the material has a significant effect on the mechanical behavior of Ni Ti file. The finite element model established for the Ni Ti file of the CM wire can accurately capture the characteristics of various deformation processes of the Ni Ti root canal file,and it has a good fit with the actual experimental curve.The finite element model can be used for study on bending properties of CM wire.
Objective: To construct a model for a controlled memory(CM) nickel-titanium(Ni Ti) file and another M-wire Ni Ti file with the same geometry by using finite element analysis. To evaluate the flexibility of a CM Ni Ti file by using three dimensional finite element method and to compare its mechanical responses with that M-wire Ni Ti. Methods: Based on the reverse engineering,the 21 mm long,25#/08 taper Hyflex NT Ni Ti file and Hyflex CM Ni Ti file were fixed by the cantilever bending model at a distance of 9. 5 mm from the tip of the file. The mechanical tester's indenter was loaded/unloaded at a distance of 3 mm from the tip of the file. The maximum displacement was 3 mm,the load displacement curve was obtained. Subsequently,by using a micro-CT to scan(layer spacing of 8 μm) Ni Ti files,and ABAQUS(6. 10) was introduced to construct a geometric model. Hyflex NT was considered as a shapememory alloy constitutive model,Hyflex CM was considered as a power-hardening plastic constitutive model,respectively. Comparing the load-displacement curve of cantilever bending in the three-dimensional finite element model with the load-displacement curve in the experiment. Results: Two tetrahedral element models were constructed,the total number of nodes was 99 353 and the total number of cells was63 744. When the loading displacement was 1 mm,the stress distribution of the cross section at 6. 1 mm from the tip of the file was observed. The upper and lower surfaces were subjected to the maximum bending stress and entered the phase transformation yield stage. The finite element simulation could clearly show the deformation of the file. Various information such as deformation characteristics and stress distribution in the process were well fitted to the actual experimental curve. Conclusion: The constitutive behavior of the material has a significant effect on the mechanical behavior of Ni Ti file. The finite element model established for the Ni Ti file of the CM wire can accurately capture the characteristics of various deformation processes of the Ni Ti root canal file,and it has a good fit with the actual experimental curve.The finite element model can be used for study on bending properties of CM wire.
引文
[1] Santos AL,BahiaMG,De ELC,et al. Comparison of the mechanical behavior between controlled memory and superelastic nickeltitanium files via finite element analysis[J]. J Endod,2013,39(11):1444-1447.
[2] Montalvao D,Alcada FS,Braz FM,et al. Structural characterization and mechanical FE analysis of conventional and M-Wire Ni-Ti alloys used in endodontic rotary instruments[J]. Sci World J,2014,2014:1-8.
[3] Montalvao D,Alcada FS. Numeric comparison of the static mechanical behavior between Pro File GT and Pro File GT series X rotary nickel-titanium files[J]. J Endod,2011,37(8):1158-1161.
[4] Auricchio F,Taylor RL. Shape-memory alloys:modelling and numerical simulations of the finite-strain superelastic behavior[J].Comput Methods Mech Engrg,1997,143(1):175-194.
[5]徐秉业.应用弹塑性力学[M].北京:清华大学出版社,1995.
[6] Santos L,López JB,Casas EB,et al. Mechanical behavior of three nickel-titanium rotary files:A comparison of numerical simulation with bending and torsion tests[J]. Mater Sci Eng C Mater Biol Appl,2014,37(1):258-263.
[7] Hou X,Yahata Y,Hayashi Y. Phase transformation behaviour and bending property of twisted nickel-titanium endodontic instruments[J]. Int Endod J,2011,44(3):253-258.
[8] Pongione G,Milana V. Flexibility and resistance to cyclic fatigue of endodontic instruments made with different nickel-titanium alloys:a comparative test[J]. Ann Stomatol,2012,3(3-4):119-122.
[9] Zinelis S,Eliades T,Eliades G. A metallurgical characterization of ten endodontic Ni-Ti instruments:assessing the clinical relevance of shape memory and superelastic properties of Ni-Ti endodontic instruments[J]. Int Endod J,2010,43(2):125-134.
[10] Yahata Y,Yoneyama T,Hayashi Y,et al. Effect of heat treatment on transformation temperatures and bending properties of nickel-titanium endodontic instruments[J]. Int Endod J,2010,42(7):621-626.
[11] Alapati SB,Brantley WA,Lijima M,et al. Metallurgical characterization of a new nickel-titanium wire for rotary endodontic instruments[J]. J Endod,2009,35(11):1589-1593.
[12] Shen Y,Coil JM,Zhou H,et al. Hy Flex nickel-titanium rotary instruments after clinical use:metallurgical properties[J]. Int Endod J,2013,46(8):720-729.
[13] Ninan E,Berzins DW. Torsion and bending properties of shape memory and superelastic nickel-titanium rotary instruments[J]. J Endod,2013,39(1):101-104.
[14] Shen Y,Qian W,Abtin H,et al. Fatigue testing of controlled memory wire nickel-titanium rotary instruments[J]. J Endod,2011,37(7):997-1001.
[2] Montalvao D,Alcada FS,Braz FM,et al. Structural characterization and mechanical FE analysis of conventional and M-Wire Ni-Ti alloys used in endodontic rotary instruments[J]. Sci World J,2014,2014:1-8.
[3] Montalvao D,Alcada FS. Numeric comparison of the static mechanical behavior between Pro File GT and Pro File GT series X rotary nickel-titanium files[J]. J Endod,2011,37(8):1158-1161.
[4] Auricchio F,Taylor RL. Shape-memory alloys:modelling and numerical simulations of the finite-strain superelastic behavior[J].Comput Methods Mech Engrg,1997,143(1):175-194.
[5]徐秉业.应用弹塑性力学[M].北京:清华大学出版社,1995.
[6] Santos L,López JB,Casas EB,et al. Mechanical behavior of three nickel-titanium rotary files:A comparison of numerical simulation with bending and torsion tests[J]. Mater Sci Eng C Mater Biol Appl,2014,37(1):258-263.
[7] Hou X,Yahata Y,Hayashi Y. Phase transformation behaviour and bending property of twisted nickel-titanium endodontic instruments[J]. Int Endod J,2011,44(3):253-258.
[8] Pongione G,Milana V. Flexibility and resistance to cyclic fatigue of endodontic instruments made with different nickel-titanium alloys:a comparative test[J]. Ann Stomatol,2012,3(3-4):119-122.
[9] Zinelis S,Eliades T,Eliades G. A metallurgical characterization of ten endodontic Ni-Ti instruments:assessing the clinical relevance of shape memory and superelastic properties of Ni-Ti endodontic instruments[J]. Int Endod J,2010,43(2):125-134.
[10] Yahata Y,Yoneyama T,Hayashi Y,et al. Effect of heat treatment on transformation temperatures and bending properties of nickel-titanium endodontic instruments[J]. Int Endod J,2010,42(7):621-626.
[11] Alapati SB,Brantley WA,Lijima M,et al. Metallurgical characterization of a new nickel-titanium wire for rotary endodontic instruments[J]. J Endod,2009,35(11):1589-1593.
[12] Shen Y,Coil JM,Zhou H,et al. Hy Flex nickel-titanium rotary instruments after clinical use:metallurgical properties[J]. Int Endod J,2013,46(8):720-729.
[13] Ninan E,Berzins DW. Torsion and bending properties of shape memory and superelastic nickel-titanium rotary instruments[J]. J Endod,2013,39(1):101-104.
[14] Shen Y,Qian W,Abtin H,et al. Fatigue testing of controlled memory wire nickel-titanium rotary instruments[J]. J Endod,2011,37(7):997-1001.