Biomimetic Study Of Erosion Resistance Characteristics And Mechanisms Of Tamarisk (Tamarix Aphylla)

Erosive wear is caused by particles that impinge on a materials surface at an angleof impingement and an impact velocity, and remove material from that surface due tomomentum effects. Helicopter propeller, aircraft engines and centrifugal fan blades areimportant mechanical parts. The tiny particles in the gas stream strike the blade surfacewhen the blades work in the gas–solid media. Erosive wear failure may occur on theblade surface. Erosion not only consumes energy and material, decreases equipmentefficiency, but also accelerates equipment failure and causes frequent componentreplacement, which lead to significant economic losses. Hence, researching on materialerosion, including the mechanism, erosion factors, and optimal selection of materials,plays a significant role in saving the materials, reducing energy consumption, andimproving economic efficiency. The general methods used to reduce erosion wear byresearchers involved enhancing the wear resistance of the material surface using texturemediated wear, friction–resistance surfaces, wear–resistant materials or coating materialswith better wear resistance.Biomimetics or bionics, a cutting–edge science, was born in1960s. Biomimetics isan emerging science of the mutual penetration and combination of biology, mathematics,materials science and engineering science. Organism forms a number of special featuresin the long process of evolution. It can effectively solve many major engineeringproblems by learning and imitating these special features. The biological characteristicsand mechanism of erosion resistant of the tamarisk （Tamarix Aphylla） were studied inthis paper. A new approach was to improve the erosion resistance of mechanical partsbased on the idea of biomimetics. This paper selects typical desert plants—tamarisk as a biological prototype. Thetamarisk was collected in Baicheng City, Jilin Province and Aksu Prefecture, XinjiangUygur Autonomous Region. The climate of two regions was analyzed. It is provided abasis for research the relationships between wind sand erosion and morphologicalstructure of the tamarisk. The windward side and leeward side surface morphology offive different diameters tamarisk in Baicheng city were analyzed by the OpticalMicroscope and reverse engineering techniques. The ring structure of the transversesection and the structure of the tangential section of the tamarisk were studied by theScanning Electron Microscopy （SEM）. The results show that the tamarisk lives in thedrought, high salinity levels and frequent sandstorms environment. The size of thewindward side surface grooves cracks was greater than that of the leeward side. Thenumber of the windward side surface grooves cracks was more than that of the leewardside. The eccentric growth of the tamarisk was a universal phenomenon. The windwardside ring width was greater than that of the leeward side.The lignin, cellulose, hemi-cellulose and CaC2O4components of the windward side,transition zone and leeward side of the tamarisk were analyzed by Fourier TransformInfrared Spectroscopy （FTIS）, Energy Dispersive Spectroscopy （EDS） and X–raydiffraction （XRD）. Their distribution was revealed. Biomechanical properties and theirdistribution of the tamarisk, strength, hardness, modulus of elasticity, toughness andresidual stress, were tested by the Universal Testing Machine （UTM） andNanoindentation. The results show that the lignin, cellulose and CaC2O4of the tamariskwindward side were higher than that of the leeward side. The comprehensivebiomechanical properties of the windward side were superior to that of the leeward side.The tensile stress of the windward side surface was greater than that of the second edgesurface.The surface and interior erosion performances of the windward side and leewardside of five different diameters tamarisk were tested by erosion testing device. Thetamarisk in Aksu Prefecture was as evidence. The regular pattern of the directioneccentric structure was analyzed. The relationships of wind-sand erosion, surfacemorphology, internal structure and biomechanical properties were studied. The erosionresistance mechanism of the tamarisk was revealed from the perspective of the surfacemorphology and biomechanics. The results show that the windward side surface andinterior erosion performance of the tamarisk have better erosion resistance propertiesthan that of the leeward side. The wind-sand erosion direction was consistent with the direction of the width ring. The Eccentric growth of the tamarisk was due to rapid celldivision. The directionally eccentric growth rings of tamarisk, which are attributed toreduced stress and accelerated cell division, promote the formation of surface cracks. Thewindward rings are more extensive than the leeward side rings. The windward surfacesare more prone to cracks.The three kinds of biomimetic models, square groove, V–shaped groove andU–shaped groove, were established on the basis of the surface morphology of thetamarisk. The biomimetic surfaces were designed and processed on the Q235steelsurface. And the erosion performance of the biomimetic samples was tested. Thebiomimetic surface erosion morphology and surface micro-strain were analyzed andcalculated by SEM and XRD. The secondary erosion mechanism in the biomimeticsurface was revealed. The results show that the optimum design parameters ofbiomimetic surfaces were as follows: V–shaped groove, groove size of3mm, groovedistance of2mm. Compared with smooth sample, the best combination of biomimeticsample could effectively improve erosion resistance performance, which increased byabout26%. The presence of the rib of the biomimetic groove surface increased erosivewear of the surface in a distal position with respect to the rib itself. Some erosionparticles rebounded backwards after impacting on the ribs. Then, they impacted on thedistal position.The erosion characteristic of the impeller blades of centrifugal fan was designed andprocessedon the basis of the results of biomimetic erosion resistance surface samples test.The biomimetic surface blades were tested by the centrifugal fan blade surface erosivewear testing device. The experimental scheme was arranged according to the experimentoptimized technology. The biomimetic blade surface morphology, size and spacing forthe influence of erosive wear characteristic were analyzed by the range analysis and theregression analysis. The results show that the bionic blades of centrifugal fan had a gooderosion resistance performance. The optimum design parameters of bionic blades were asfollows: V–groove surface, groove size of4mm, groove distance of2mm. The bionicblades could effectively improve erosion resistance performance of the impeller, whichincreased by about29%. The regression equation for V–shaped groove isy_V=74.84-1.83z₂+4.33z₃Where groove size z2, groove distance z3.The distribution of the large–diameter cells and the micro cells in the cell wall of the transverse section and tangential section of the tamarisk and its charring was studied. Theepoxy erosive surface self-healing model using the channel of the tamarisk wasestablished. The Liquid epoxy resin flowing characteristics inside the tamarisk channelwere analyzed. The biomimetic self-healing properties of the epoxy eroded surface werestudied. The results show that the epoxy eroded surface was successful healing by usingchannel of the tamarisk and its charring. The epoxy had better flowing properties of thecharring than that of the tamarisk. It provides the new ideas and methods to designself-repair materials.