骨的电致伸缩效应研究

发布时间：2018-09-10 05:53

【摘要】：骨的力电性质,即骨内应力产生电位的情况,产生于两种机理,压电效应和动电现象。一般来说,骨在电场中会产生弯曲变形一般是由于逆压电效应造成的,目前许多对于骨的研究都是基于骨的压电效应展开的。但是作为一种二次效应,一般电介质内部的压电效应与电致伸缩效应一般是同时发生的,而牛干骨在均匀电场下是否会产生电致伸缩效应却鲜有人进行研究。本文的目的就是通过实验的方法,对牛干骨是否会产生电致伸缩效应进行研究。本文设计了分离的电极对牛干骨试件加载均匀电场,减少了原来预置电极对试件弯曲的影响。用高分辨率显微镜分别对加载前后试件顶端截面进行图像采集,然后通过数字图像相关的方法计算得到试件在加载电压下的位移。通过改变电场的大小及方向,对试件在电场下的位移情况进行了测量,发现试件的弯曲方向与加载电场的方向无关,并且弯曲位移大小与加载电压的二次方成正比,所以弯曲现象与电致伸缩效应相符,发生此现象的原因可能是试件内部的电荷与带电的电极相互吸引引起,此时试件可以等效于受均布载荷的悬臂梁,并计算了试件弯曲时的最大应变值。本文也测试了不同厚度下的试件在电场中的位移,并将试件的弹性模量和惯性矩引入到数据处理当中,对试件在电场中所受的等效均布载荷进行了分析,发现不同厚度下的试件所受的载荷有集中趋势,并且载荷也与电压的平方成正比。
[Abstract]:The electromechanical properties of bone, I. e., the potential generation of bone stress, arise from two mechanisms, the piezoelectric effect and the electrokinetic phenomenon. Generally speaking, the bending deformation of bone in electric field is usually caused by inverse piezoelectric effect. At present, many researches on bone are based on the piezoelectric effect of bone. However, as a kind of secondary effect, the piezoelectric effect and electrostrictive effect in general dielectric generally occur at the same time, but there are few studies on whether the bovine dry bone will produce electrostrictive effect under the uniform electric field. The purpose of this paper is to study the electrostrictive effect of dried bovine bone by experimental method. In this paper, the separation electrode is designed to load uniform electric field on the dried bone specimen, which reduces the effect of the preset electrode on the bending of the specimen. The top section of the specimen before and after loading was collected by high resolution microscope, and then the displacement of the specimen under the loading voltage was calculated by the method of digital image correlation. By changing the magnitude and direction of the electric field, the displacement of the specimen under the electric field is measured. It is found that the bending direction of the specimen is independent of the direction of the loading electric field, and the magnitude of the bending displacement is proportional to the quadratic power of the loading voltage. So the bending phenomenon is consistent with the electrostrictive effect, and the reason for this phenomenon may be that the charge inside the specimen and the charged electrode attract each other, so that the specimen can be equivalent to the cantilever beam subjected to uniform load. The maximum strain value of the specimen in bending is calculated. In this paper, the displacement of specimens with different thickness in electric field is also measured, and the elastic modulus and moment of inertia of the specimen are introduced into the data processing, and the equivalent uniform load on the specimen in the electric field is analyzed. It is found that the load of specimens with different thickness is concentrated and the load is proportional to the square of voltage.
【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

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