骨的逆压电效应的实验探究

发布时间：2018-05-29 12:20

本文选题：骨 + 压电性　；参考：《天津大学》2012年硕士论文

【摘要】：骨是具有压电性的各向异性材料,然而由于骨的复杂的微观结构,其压电性质也非常复杂。骨内由于应力的作用产生电信号,电信号有可能影响到骨细胞的生长,因此研究骨的压电效应有重要的现实意义。然而仅仅研究骨的正压电效应是不够的,不足以全面掌握骨压电效应的具体性质。因此也同样需要我们对骨的逆压电效应进行探究。本实验研究测量了牛骨薄梁试样逆压电效应弯曲变形的位移。选取7个牛骨试件,分别在其厚度为1mm、0.8mm、0.6mm、0.5mm、0.3mm(高度均为50mm,宽均为10mm)的状态下进行试验。牛骨试件被放置于由两个电极板产生的外电场中(电极板外接高压稳态直流电源)。在外电场的作用下(外接电源分别在200v、400v、600v、800v、1000v的状态下进行实验)骨试件会发生弯曲变形,即骨的力电性质。利用高倍数字光学显微镜以及数字图像处理技术观测和计算骨试件自由端的位移。研究骨逆压电效应的各种性质。通过实验发现:同一试件,随着电压的减小,试件位移逐渐减小。不同试件之间,相同电压作用下,试件位移虽然不同,但是随着电压的变化,其位移大小的变化趋势是一样的。同一试件,随着厚度的减小,在相同电压下试件位移变大。在外电场作用下不同试件之间,随着厚度的变化(电压相同)位移大小不同,但趋势相同。不同的试件在相同厚度的情况下,相同外电压作用下,位移大小不同,有的相差很大。同时实验研究了产生外电场的电极板在一端接地的情况下试件位移的大小及其它性质。采用4种加载电场的方式进行测试,第1、2种加载方式以及第3、4种加载方式分别为不改变接地的电极而是通过电源输出电压的极性改变电场方向,然而前两种加载方式与后两种加载方式接地的极板方向不同,第1、2种加载方式右侧极板接地,第3、4种加载方式左侧极板接地。在通过改变电源输出电压的极性来改变电场方向的情况下,牛骨薄梁试样在外电场作用下位移的方向没有发生变化,且大小几乎相同。而在通过仪器自身的改变(改变接地极板的方向)来改变电场方向的情况下,牛骨薄梁试样在外电场作用下位移的方向会发生变化,正向位移大小要大于负向位移的大小,这种现象随着外接电压的增加以及牛骨试件厚度的减小而越发明显。
[Abstract]:Bone is an anisotropic material with piezoelectric properties, but its piezoelectric properties are very complicated because of the complex microstructure of bone. Because of the effect of stress in bone, electrical signals may affect the growth of bone cells, so it is very important to study the piezoelectric effect of bone. However, it is not enough to study the positive piezoelectric effect of bone. Therefore, we also need to explore the inverse piezoelectric effect of bone. In this paper, the displacement of bending deformation of bovine bone thin beam specimen with inverse piezoelectric effect has been measured. Seven bovine bone specimens were tested under the condition of 0. 3 mm (50 mm in height and 10 mm in width) with a thickness of 0. 6 mm and 0. 5 mm. The bovine bone specimen is placed in an external electric field generated by two electrodes (the electrode plate is externally connected to a high voltage steady-state DC power supply). Under the action of an external electric field (the external power supply is tested at the condition of 200v / 400v / 600V / 100V respectively), the bone specimen will bend and deform, that is, the mechanical and electrical properties of the bone. The displacement of free end of bone specimen was observed and calculated by high power digital optical microscope and digital image processing technology. The properties of inverse piezoelectric effect of bone were studied. It is found that the displacement of the same specimen decreases with the decrease of voltage. The displacement of different specimens is different under the same voltage, but the change trend of displacement is the same with the change of voltage. With the thickness decreasing, the displacement of the same specimen increases at the same voltage. Under the action of external electric field, the displacement of different specimens varies with the change of thickness (same voltage), but the trend is the same. Under the same thickness and the same external voltage, the displacement of different specimens varies greatly. At the same time, the displacement and other properties of the electrode plate with external electric field are studied under the condition of earthing at one end. Four ways of loading electric field were used to test. The first two loading modes and the third four loading modes changed the electric field direction by the polarity of the output voltage instead of changing the grounding electrode, respectively. However, the first two loading modes are different from the latter two ways in the direction of the earthing plate, the first and the second loading modes are the right side polar plate grounding, and the third one is the fourth loading mode, the left pole plate is grounded. When the direction of electric field is changed by changing the polarity of the output voltage of the power supply, the direction of displacement of the specimen of the thin beam of bovine bone does not change under the action of the external electric field, and the magnitude is almost the same. In the case of changing the direction of the electric field by changing the instrument itself (changing the direction of the electrode plate), the direction of the displacement of the specimen of the thin beam of bovine bone will change under the action of the external electric field, and the magnitude of the forward displacement is larger than the magnitude of the negative displacement. This phenomenon becomes more and more obvious with the increase of the external voltage and the decrease of the thickness of the bovine bone specimen.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：O482.41;R312

【参考文献】