仿生层结构耐冲蚀性能试验研究与模拟分析

发布时间：2018-07-21 14:52

【摘要】：磨损失效是工程应用中设备的主要失效形式，而冲蚀磨损导致的失效占据了较大的比例。仿生学是一门逐步走向成熟的学科，，通过研究生物体的结构特点、性状、行为、功能、原理及相互作用，择优模仿并应用于工程当中，用以优化装置和机器的性能。本文将以仿生学为研究手段提高材料的耐冲蚀性能。现代工程应用中对材料耐冲蚀性能的要求越来越高，如何在保证工况要求的前提下提高材料的耐冲蚀性能成为了重要的研究方向。沙漠蜥蜴能够生活在风沙冲击极为严重的沙漠之中，说明其表皮分层结构优异的耐冲蚀性能。本文以生活在沙漠中的蜥蜴为仿生对象，根据已有研究成果，进一步研究沙漠蜥蜴头部和背部表皮结构特点及表皮分层结构耐冲蚀磨损的机理。首先，对研究意义做出论证。综合相关的冲蚀磨损理论，结合靶体表面发生变形后的情形进行冲蚀磨损机理分析，证明了变形的产生很大程度上影响了冲蚀磨损。在工程应用中，当延性材料受到固体粒子冲击时，不论角度是大是小，变形的产生都会增加冲蚀磨损率，应变越大，冲蚀磨损越严重。其次，利用应力波基本理论分析层结构的动态力学特性。通过公式得出应力波从波阻抗较大的材料传入波阻抗较小的材料时产生反射卸载，相当于减震缓冲；而当应力波反方向传播时则会引起反射加载，导致透射强于入射。通过应力波传播时内碰撞的分析可得出仿生层结构能有效降低材料的破坏。以上结论证明了仿生层结构力学特性的优越。再次，根据研究方向进行冲击应变测试试验，研究靶体受冲击时的应力应变大小并分析不同结构的性能优劣。采用DH-5923（4CH）动态信号测试采集仪及DHDAS（5923-1394）信号分析系统对靶体的冲击应变做采集和分析，以304不锈钢及轧制纯铜作为靶体，利用摆锤对不同仿生层结构进行90°冲击。试验分为单因素对比试验、多因素正交试验及三层结构对比试验三部分：单因素对比试验得出性能最优结构为304不锈钢/硅胶，耐冲蚀性与仿生层结构中两种材料的波阻抗比有关；正交试验分析了靶体材料、层数、冲击速度及软层材料等因素，利用SPSS软件对试验数据进行了方差和均值分析，得出靶体材料对耐冲蚀性能影响最大，之后依次为冲击速度、软层材料及结构层数，并得出当靶材为304不锈钢、层结构为三层、冲击速度为V2及软层材料为硅胶时耐冲蚀性能最好；三层结构对比试验分析下层硬结构波阻抗差异对耐冲蚀性能的影响，对比得出，下层结构波阻抗大于靶体材料波阻抗时性能最优。最后，本文通过ABAQUS软件对试验中的层结构进行了球形金属单粒子冲击的数值模拟分析，通过分析后的数据得出了与冲击应变测试试验相同的结论，更有力的证明了实体试验中的结论。本文通过理论、试验及模拟分析对仿生层结构进行了细致的研究验证，得出多个相关结论，研究内容及方法为仿生层结构在材料耐冲蚀及碰撞耐冲击等领域提供了有力的依据。
[Abstract]:Wear failure is the main failure form of equipment in engineering applications, and the failure of erosion and wear leads to a larger proportion. Bionics is a gradually mature subject. By studying the structure characteristics, characters, behavior, functions, principles and interaction of organisms, the imitation and should be used in the engineering to optimize the device and to optimize the device. The performance of the machine will be improved by bionics.
The demand for erosion resistance of materials is becoming more and more high in modern engineering applications. How to improve the corrosion resistance of materials under the condition of ensuring the working conditions has become an important research direction. Desert lizard can live in the desert with severe wind and sand impact, indicating the excellent erosion resistance of the layer structure of its epidermis. The lizards living in the desert are bionic objects. According to the existing research results, we further study the characteristics of the skin structure of the head and back of the desert lizard and the mechanism of erosion and abrasion resistance of the stratified structure of the epidermis.
First, the significance of the research is demonstrated. The comprehensive related erosion wear theory is combined with the analysis of the erosion wear mechanism of the target body after the deformation of the surface. It is proved that the formation of the deformation has a great influence on the erosion and wear. In engineering application, when the ductile material is impacted by the solid particles, the deformation is large and small. The erosion wear rate is increased, and the larger the strain is, the more serious erosion wear is.
Secondly, the dynamic mechanical characteristics of the layer structure are analyzed by the basic theory of stress wave. It is found that the stress wave produces the reflection unloading when the material with a larger impedance of the material has a smaller impedance of the material afferent wave, which is equivalent to the damping buffer, and when the reverse direction of the stress wave propagates, the back loading will be caused, which leads to the transmission stronger than the incident wave. The analysis of internal collisions during propagation shows that the biomimetic structure can effectively reduce the damage of materials. The above conclusion proves that the mechanical properties of bionic layers are superior.
Thirdly, according to the research direction, the impact strain test is carried out to study the size of the stress and strain of the target body and analyze the performance of different structures. The impact strain of the target body is collected and analyzed by DH-5923 (4CH) dynamic signal testing collector and DHDAS (5923-1394) signal analysis system, and 304 stainless steel and rolled pure copper are used as the analysis system. The target body has a 90 degree impact on the structure of different biomimetic layers by the pendulum. The test is divided into single factor contrast test, multi factor orthogonal test and three layer structure contrast test, three parts: the optimum structure of the single factor comparison test is 304 stainless steel / silica gel, and the resistance to erosion is related to the wave impedance ratio of the two materials in the biomimetic layer; The test analysis of the target material, the number of layers, the impact velocity and the soft layer material, using the SPSS software to analyze the variance and the mean value of the test data. It is concluded that the target material has the greatest impact on the erosion resistance, followed by the impact velocity, the soft layer material and the structure layer, and the target material is 304 stainless steel, the layer structure is three layers and the impact is impacted. When the velocity is V2 and the soft layer material is silica gel, it has the best erosion resistance, and the three layer structure contrast test analyses the influence of the difference of the wave impedance of the lower layer on the erosion resistance. The comparison shows that the performance of the lower structure wave impedance is greater than the wave impedance of the target material.
Finally, through the ABAQUS software, the numerical simulation analysis of the single particle impact of the spherical metal in the test is carried out. The same conclusion is obtained by the analysis of the data after the analysis of the impact strain test. The conclusion is proved more strongly in the solid test.
In this paper, through the theory, test and simulation analysis, the structure of the bionic layer is carefully studied and verified, and many relevant conclusions are obtained. The research contents and methods provide a powerful basis for the biomimetic layer structure in the field of material erosion resistance and impact and impact resistance.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG174.4

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