不同生境下蝎子体表抗冲蚀特性的比较仿生研究

发布时间：2018-07-28 17:16

【摘要】：作为机械零部件的三大主要失效形式之一,磨损造成了严重的经济、能源损失与材料浪费。冲蚀磨损是磨损的重要分支领域,它广泛存在于汽轮机、管道、离心式压缩机、离心风机、旋风分离器、气体钻井钻杆、节流管汇、天线罩、直升机旋翼等机械产品上,已成为设备失效的重要原因之一。目前,科研人员主要通过选用耐磨材料、采取表面强化工艺或热处理技术来提高材料表面的抗冲蚀磨损性能,然而这些方法并没有达到理想的效果。因此,寻求一种优异的抗冲蚀磨损新技术、新工艺已经成为材料科学研究的热点与难点。受仿生学启发,本文以生活在沙漠、灌木丛和半干旱地区的黑粗尾蝎(Parabuthus transvaalicus)为生物原型,以生活在亚洲热带雨林中的彼得异蝎(Heterometrus petersii)为参比对象,对两种蝎子的生境特征进行了差异性分析,采用显微分析手段从4个层次对其体表形态及结构进行了对比研究。发现蝎子的各背板之间通过节间膜连接形成凹槽,且黑粗尾蝎体表的凹槽宽度大于彼得异蝎的凹槽宽度;与彼得异蝎相比,黑粗尾蝎背板表面分布有密度不均、粒径更大的凸包颗粒,且其在背板侧部最为密集。在凸包与凸包之间,黑粗尾蝎背板表面还覆盖有微米级的类正六边形凹坑结构。对比两种蝎子的背板厚度,发现黑粗尾蝎的背板厚度更大,且其随位置的不同而出现明显的变化规律。此外,两种蝎子的背板都存在梯度分层结构,其中内表皮由纤维螺旋排列形成Bouligand结构,内表皮上的蜂窝微孔道也进一步增强了背板的顺应性,两种蝎子背板横截面的差异性主要体现在各分层之间的厚度。由于冲蚀磨损性能与材料本身的性能密切相关,因此,对两种蝎子背板的化学成分与宏微观力学性能进行了研究。发现黑粗尾蝎背板中含有Fe元素,且Fe元素的分布特性与蛋白质的分布特性相一致;彼得异蝎背板中基本不含Fe元素,且所含蛋白质也无显著性分布规律。此外,黑粗尾蝎背板的弹性模量大于彼得异蝎相应背板的弹性模量。在背板横截面弧形方向上,黑粗尾蝎背板的微观硬度H、弹性模量E以及H3/E2值,均呈现出侧部最大、中间次之、边缘最小的变化规律,彼得异蝎的以上力学参数为随机波动数值。对于以上两种蝎子,其背板的微观硬度与弹性模量在沿上表皮到内表皮的方向上均呈现出逐渐减小的变化趋势。对于黑粗尾蝎背板横截面的凸包与非凸包位置,前者的微观硬度、弹性模量以及H3/E2值均要显著优于后者。在研究了两种蝎子体表的生物学以及材料学特征之后,通过设计小型生物体冲蚀磨损试验装置,对活体黑粗尾蝎、彼得异蝎体表以及普通玻璃板的冲蚀磨损性能进行了对比研究,发现活体黑粗尾蝎体表具有最为优异的抗冲蚀磨损性能。之后,围绕体表形态与结构、内部软硬(刚柔)梯度分层结构、化学成分以及力学性能对黑粗尾蝎的抗冲蚀机理进行了多角度分析。ANSYS-FLUENT流体仿真分析发现,V型槽、凸包以及正六边形凹坑对蝎子体表构成了全方位防御;赫兹接触以及赫兹弹性碰撞理论的结果证明,梯度分层结构不仅避免了蝎子体表被直接磨损穿透,而且还缓释了粒子的冲击能量;Fe参与到了蛋白质基质的交联之中,使得黑粗尾蝎背板具有较高的弹性模量,从而使其具有更为优异的抗冲蚀磨损性能。此外,黑粗尾蝎对风沙环境的适应性,导致背板侧部逐渐进化出较厚的外骨骼和更密集的体表形态。在对黑粗尾蝎的形态、结构及尺寸信息进行提取后,结合加工工艺精度,设计了V、VC、VH200、VH300、VH500、VCH200、VCH300、VCH500共8种具有复合结构的仿生表面样件,为了对比分析,同时设计了一个同样大小的光滑样件。以EOS Stainless Steel GP1金属粉末为打印材料,利用EOSINT M280激光烧结系统分别打印出了以上9种试验样件。接着,采用线切割设备、砂轮机以及喷砂机对样件进行了后处理,用自制的喷射式冲蚀磨损系统对样件表面进行了冲蚀测试。试验结果表明,复合结构有助于提升样件表面的冲蚀磨损性能,且V型槽对结果的影响最大,其次为凸包,正六边形凹坑结构的影响最小。与光滑样件相比,VCH500样件的抗冲蚀磨损性能提高了约31.9%。
[Abstract]:As one of the three major failure forms of mechanical parts, wear and tear have caused serious economic, energy loss and material waste. Erosion wear is an important branch of wear and tear. It is widely used in steam turbine, pipe, centrifugal compressor, centrifugal fan, cyclone separator, gas drilling rig, throttle manifold, radome, helicopter rotor. On mechanical products, it has become one of the important reasons for the failure of the equipment. At present, the researchers mainly use the wear-resistant material to improve the erosion resistance and wear resistance of the material surface by using the surface strengthening technology or heat treatment technology. However, these methods have not reached the ideal results. Therefore, a new technique for resisting erosion and abrasion is sought. The new technology has become a hot and difficult point in the research of material science. Inspired by bionics, this paper uses the Parabuthus transvaalicus (Parabuthus transvaalicus) living in the desert, Bush and semi-arid area as the biological prototype, with the Heterometrus petersii of the Asian tropical rainforest as the reference object, and to the birth of two kinds of scorpions. The morphology and structure of the body surface were compared by microanalysis. It was found that the back plates of the scorpion were connected through the internode membrane to form the grooves, and the groove width of the black rough tail Scorpion was larger than the groove width of Peter. Compared with Peter, the black coarse tail scorpion back plate table was compared. The surface distribution has uneven density and larger particle size, and it is the most dense in the side of the back plate. Between the convex hull and the convex hull, the surface of the black coarse tail scorpion is also covered with a micron like hexagonal concave pit structure. Comparing the thickness of the back plate of the two scorpion, it is found that the back plate of the black scorpion is more thick and appears clearly with the different position. In addition, there are gradient stratification in the back plates of the two scorpion, in which the inner epidermis is formed by the spiral arrangement of the fibers, and the cellular microchannels on the inner epidermis further enhance the compliance of the back plates. The difference of the cross section of the two kinds of scorpion back plates should be reflected in the thickness between the layers. Because of the erosion mill, the difference of the cross section of the two kinds of scorpion backplates should be reflected. The loss performance is closely related to the performance of the material itself. Therefore, the chemical composition and macro and micro mechanical properties of the two kinds of scorpion backplates are studied. It is found that the Fe element is contained in the black coarse tail scorpion back plate, and the distribution characteristics of the Fe element are in accordance with the distribution characteristics of the protein. The Peter backboard contains basically no Fe elements, and the protein is also contained. In addition, the elastic modulus of the back plate of the black rough tail scorpion is larger than the elastic modulus of the corresponding back plate of Peter. In the curved direction of the cross section of the back plate, the microhardness H, the modulus of elasticity E and the H3/E2 value of the back plate of the black coarse Scorpion are all showing the maximum side of the side, the middle time, the smallest edge, and the above forces of the Peter scorpion. For the above two scorpion, the micro hardness and elastic modulus of the backplane of the above two scorpion are gradually decreasing in the direction of the upper epidermis and the upper epidermis. For the convex and non convex positions of the cross section of the black coarse scorpion back plate, the micro hardness, the elastic modulus and the H3/E2 value of the former are superior to those of the scorpion. After studying the biological and material characteristics of two kinds of scorpion body surface, the erosion wear performance of the living body black coarse scorpion, Peter scorpion body surface and the ordinary glass plate was compared by the design of the small biological erosion wear test device. It was found that the body surface of the living body black coarse tail scorpion has the most excellent erosion resistance. .ANSYS-FLUENT fluid simulation analysis shows that V groove, convex hull and hexagonal pits constitute the full defense of the scorpion body surface and Hertz contact. The results of the Hertz elastic collision theory show that the gradient stratified structure not only avoids the direct wear and penetration of the scorpion body surface, but also sustains the impact energy of the particle, and Fe participates in the cross-linking of the protein matrix, making the black coarse tail scorpion back have a higher elastic modulus, thus making it have a more excellent erosion resistance. In addition, the adaptability of the black coarse tail scorpion to the sand environment leads to the gradual evolution of the thicker exoskeleton and more dense body surface morphology in the side of the backplane. After the extraction of the shape, structure and size information of the black coarse scorpion, combined with the processing precision, a total of 8 kinds of complex knot, V, VC, VH200, VH300, VH500, VCH200, VCH300, VCH500, are designed. In order to compare and analyze the sample of the bionic surface, a smooth sample of the same size was designed for comparison and analysis. With EOS Stainless Steel GP1 metal powder as the printing material, the above 9 samples were printed out by the EOSINT M280 laser sintering system. Then, the sample was carried out by wire cutting equipment, grinding wheel machine and sandblasting machine. The results show that the composite structure helps to improve the erosion and abrasion performance of the sample surface, and the V groove has the greatest impact on the results, followed by the convex hull, the regular hexagonal concave structure has the smallest impact. Compared with the smooth sample, the impact of the VCH500 sample is compared with the smooth sample. The erosion and wear performance improved by about 31.9%.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：Q811

【参考文献】