Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Experimental Study on Drag Reduction Characteristics of Bionic Earthworm Self-Lubrication Surface

Experimental Study on Drag Reduction Characteristics of Bionic Earthworm Self-Lubrication Surface Hindawi Applied Bionics and Biomechanics Volume 2019, Article ID 4984756, 8 pages https://doi.org/10.1155/2019/4984756 Research Article Experimental Study on Drag Reduction Characteristics of Bionic Earthworm Self-Lubrication Surface 1,2 3 3 2 3 Guomin Liu, Xueqiao Wu, Meng Zou , Yuying Yan, and Jianqiao Li College of Civil Engineering, Jilin Jianzhu University, Changchun 130118, China Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, UK Key Laboratory of Bionic Engineering, Jilin University, Changchun 130022, China Correspondence should be addressed to Meng Zou; zoumeng@jlu.edu.cn Received 24 June 2019; Accepted 20 September 2019; Published 23 October 2019 Academic Editor: Raimondo Penta Copyright © 2019 Guomin Liu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. In the present study, a coupling bionic method is used to study the drag reduction characteristics of corrugated surface with lubrication. In order to test the drag reduction features, bionic specimen was prepared inspired by earthworm surface and lubrication. Based on the reverse engineering method, nonsmooth curve of earthworm surface was extracted and the bionic corrugated sample was designed, and the position of lubrication hole was established by experimental testing. The lubricating drag reduction performance, the influence of normal pressure, the forward velocity, and the flow rate of lubricating fluid on the forward resistance of the bionic specimens were analyzed through a single factor test by using the self-developed test equipment. The model between the forward resistance and the three factors was established through the ternary quadratic regression test. The results show that the drag reduction effect is obvious, the drag reduction rate is 22.65% to 34.89%, and the forward resistance decreases with the increase of the forward velocity, increases with the increase of the normal pressure, and decreases first and then becomes stable with the increase of flow rate of lubricating fluid. There are secondary effects on forward resistance by the three factors, and the influencing order is as follows: normal pressure>flow rate of lubricating fluid>forward velocity. [9, 10] put forward the surface electroosmosis technology 1. Introduction according to the phenomenon of earthworm surface electro- Soil adhesion is a major problem in the field of ground trans- osmosis and applied it to soil-engaging components. In the portation, excavation, and farming machinery. The adhesion late 1990s, Ren et al. [11] studied the surface flexibility of of soil to soil-engaging components will seriously affect the earthworms and their antiviscosity characteristics. After 2004, Sun et al. [12, 13] and Li et al. [14–16] have successively working efficiency and quality of ground machinery, thus increasing energy consumption [1–4]. With the aggravation carried out biomimetic research on the viscosity reduction of energy and environmental crises, it is imperative to design and drag reduction of earthworm’s nonsmooth surface. Shi and produce soil-engaging components with high efficiency et al. [17] carried out a biomimetic study on earthworm and low consumption. Earthworm is a typical soil animal, telescopic motion. Zu and Yan [18, 19] used the lattice which has an excellent function of reducing drag and remov- Boltzmann method to simulate the surface electroosmosis ing soil in long-term evolution. It can also move freely in of earthworms and further studied the adhesion reducing clayey soil and does not have clay [5, 6]. Since early 1990s, the mechanism of earthworm surface electroosmosis. These scholars at home and abroad have gradually carried out studies mainly focus on the unit biomimetic of a certain bionic research on reducing soil adhesion and scouring soil aspect or a certain factor. of earthworm. Li et al. [7] carried out the extraction of earth- With the deepening of bionic research, researchers have worm surface fluid and studied the adhesion reducing the found that the functions, which biologically adapt to the mechanism of earthworm surface self-lubrication. Sun et al. external environment, are not only the role of a single factor [8] measured the surface potential of earthworms; Ren et al. or the simple addition of multiple factors but also the results 2 Applied Bionics and Biomechanics selecting the yellow clay of Changchun city, when the soil of synergistic action that a variety of interdependent, mutually affecting factors are coupled through a certain mechanism moisture content was 22.2% and the forward velocity was [20, 21]. The research shows that earthworm has an excellent 200 cm/min, the experiment was carried out with five differ- ent normal pressure conditions, and each group was repeated function of viscosity reduction and drag reduction, which is the result of multifactor coupling action such as body surface three times. As shown in Figure 2, the adhesion was at a nor- structure, body surface flexibility, body surface electroosmo- mal pressure of 34 N. sis, body surface lubrication, and its unique movement mode The adhesion data is shown in Table 1. According to [22–25]. Based on the nonsmooth structure and the self- Table 1, there is more adhesion to the head and body, but there is no adhesion in the tail. lubricating characteristics of earthworm surface, this paper discusses the drag reduction characteristics of earthworm In order to prevent clogging, the bionic dorsal foramen by a dual-coupling biomimetic method, in order to provide was designed in the top of the sulcus of the head and body a new theory and method for the design of soil-engaging backward-forward direction according to the adhesion and components with high efficiency and low consumption. model characteristics. They are including the anterior fora- men of the head (HF), the posterior foramen of the head (HB), the anterior foramen of the body (BF), and the poste- 2. Materials and Methods rior foramen of the body (BB), as shown in Figure 3. 2.1. Coupling Bionic Sample Design. Earthworms are com- mon animals that can move freely in the soil; it can adapt 2.2. Test Rig and Methods. According to the test require- ments, the test rig for lubricating and drag reduction perfor- to different soil environments. The viscosity reduction ability of earthworms mainly depends on its flexible nonsmooth mance of soil-engaging components was designed, as shown in Figure 4(a). The rig consists of support frame, soil bin, body surface, bioelectroosmotic system, surface lubrication, corrugated body surface, and other factors [12]. In this paper, motion control device, data acquisition device, and lubrica- Eisenia foetida was used as bionic prototype, and according tion adjustment device. The soil is fixed on the support frame, and the motion to the previous studies, the corrugated body surface of earth- worm has the characteristics of reducing viscosity and drag control device is fixed directly above the soil bin, mainly [21]. The effect of viscosity and drag reduction of the differ- including servomotor, pulley motion pair, and sliding plate, which is responsible for the bidirectional motion of the ent states of the body from large to small is contraction state, motionlessness state, and stretched state, and the effect of soil-engaging components in the soil bin. The lubrication adjustment device is fixed on the upper left side of the soil viscosity and drag reduction of the head is more obvious than that of the body. Therefore, the head contraction state of bin, mainly including peristaltic pump, peristaltic pump earthworm has the best viscosity and drag reduction effect frame, and water tank, which can convey lubricating fluid during the movement of soil-engaging components. The [14, 15], as shown in Figure 1(a). Based on the reverse engineering method, the corrugated pump is compiled by external software and connected to the computer. According to the conditions, the flow rate body surface of earthworm was scanned by a 3D laser scan- ner, and the data of point cloud was processed by Geomagic can be set and the number of the opening pump and the software. There are about ten knots involved in each lubricating position can also be set, so that the flow rate can be accurately adjusted. The data acquisition device is fixed extension-contraction movement of earthworms, the head and body are the main position of soil adhesion and force, at the top of the soil bin, including computer, object board, and angle steel, which is responsible for collecting data and and the tail are weak [14–16], so they are equivalent to a cyl- inder when designing biomimetic samples, composed of 10 controlling each device compiled by software. body knots, and the tail curve is designed as the symmetrical After the equipment connection is completed, the bionic sample is placed in the soil bin and the moving speed, the curve of the head. Through the commands of three-point arc, tangent arc, and curve curvature extension in CAXA, the flow rate, and the number and position of the peristaltic pump are set up by the control software, and then the motor smooth curve which is close to the contour curve of the cor- rugated body surface of earthworm is drawn, and the coor- is started. The lead screw moves the bionic sample forward, dinate point data of the smooth curve are extracted. Then, and the data acquisition is transmitted to the computer by the data collector in actual time. The force sensor is Kistler the spline curves of the head shape are drawn by using coor- dinate points. At last, amplifying the size by six times for Triaxial Force Sensor Type 9027C and assembly located and fixed between the traction rope and moving plate. The engineering needs, the biomimetic sample was printed in 3D. As shown in Figure 1(b), the length is 207.18 mm, the test image and the data can be obtained by software. For width is 62.59 mm, the thickness is 31.28 mm, the sample the testing procedure, see Figure 4(b). material is photosensitive resin, and the printing precision is 0.1 mm. For comparative analysis, a smooth specimen of 3. Test and Result Analysis the same size was designed, as shown in Figure 1(c). The lubrication hole’s position of earthworm surface has 3.1. Single Factor Test and Result Analysis. Forward velocity, direct influence on the lubricating effect [26], and the hole flow rate of lubricating fluid, and normal pressure are impor- location of the corrugated surface sample is determined by tant factors affecting forward resistance. In order to investi- the test method. According to previous studies, normal pres- gate their effects, a single factor test was carried out when sure is the most important factor affecting adhesion force. So, soil moisture content was 22.2% with lubrication and Applied Bionics and Biomechanics 3 31.28 mm 4.7 mm 54.24 m 98.7 mm 54.24 m 0.44 mm Unit size Head Body Tail (a) Surface specimen of earthworm (b) Bionic specimen (c) Smooth contrast specimen Figure 1: Specimen. resistance is 18.01 N~70.08 N without lubrication and 11.23 N~48.47 N with lubrication, and the drag reduction rate is 36.27%~58.46%. With the increase of normal pressure, the reducing effect is more and more obvious, and the for- ward resistance of unlubricated and lubricated conditions will increase continuously, because the contact area between corrugated surface and soil increases with the increase of nor- mal pressure, and the gap between corrugated surface and soil decreases, which make soil compacted and the friction resistance increased. Figure 2: Adhesion when normal pressure was 34 N. When the normal pressure is 34 N and the forward velocity is 300 cm/min, the effect of the flow rate of lubricat- Table 1: Adhesive quality of different parts. ing fluid on the forward resistance is shown in Figure 5(c). From Figure 5(c), it can be seen that the forward resistance Head Body Tail Total Normal decreases first and then remains unchanged with the increase adhesion adhesion adhesion adhesion pressure (N) of the flow rate of the lubricating fluid. When the velocity rate (g) (g) (g) (g) is 0.08 ml/s, the forward resistance is 21.32 N that is close to 17 7.4 6.53 0.29 14.22 20.09 N when the rate is 0.1 ml/s. This is because with the 34 13.83 6.95 0.09 20.87 increase of the flow rate of the lubricating fluid, the fluid fully 51 16.21 9.58 0.22 26.01 permeates into the contact interface between corrugated sur- 68 19.36 13.17 0.46 32.99 face and soil and then forms the interfacial lubrication, mak- 85 28.02 14.44 0.12 42.58 ing the resistance decrease. When it increases to a certain condition, the interface water film is saturated, so the forward resistance is almost unchanged. nonlubrication, and three repeated tests were carried out to 3.2. Ternary Quadratic Regression Combination Test and reduce the error. The test plan is shown in Table 2. Result Analysis. In order to further explore the effect of these The effect of forward velocity on forward resistance three factors and establish the equation between forward is shown in Figure 5(a) when the normal pressure is 34 N resistance and each factor, the three-element quadratic and the flow rate of lubricating fluid is 0.06 ml/s. From Figure 5(a), it can be seen that the forward resistance regression combination test [27] was carried out, and the repeated test with m is between 26.32 N~33.14 N without lubrication and =3, r =1:831 was selected. The factor 18.11 N~23.46 N with lubrication, and the drag reduction level and coding are shown in Table 3. According to the testing requirements and the designing rate is 24.19% to 33.71%. In addition, the forward resistance decreases with the increase of the forward speed under both principle of quadratic regression orthogonal, the experimen- lubricated and nonlubricated conditions. Without lubrica- tal scheme is worked out and the regression coefficients and tion, it decreases obviously with the increase of velocity, squares of each sequence are calculated as shown in Table 4. because when the velocity is small, the contact time between By testing the regression coefficient, the equation is obtained as follows: corrugated body surface and soil becomes longer and the dis- turbance to the soil increases in the course of movement. With lubrication, the forward resistance of 500 cm/min is ̂y =16:10 + 5:68x − 0:81x − 1:29x 1 2 3 ð1Þ greater than that of 400 cm/min, which is due to that the fluid 2 2 2 +1:61x − 0:96x − 0:23x : 1 2 3 cannot penetrate the interface between corrugated surface and soil sufficiently with the increase of velocity, resulting Therefore, the sum of regressing squares is in a reduced lubrication effect. When the forward velocity is 300 cm/min, and the flow rate of lubricating fluid is 0.06ml/s, the effect of normal S = S + S + S + S + S + S = 287:69, 回 x x x ′ ′ ′ x x x 1 2 3 1 2 3 ð2Þ pressure on the forward resistance is shown in Figure 5(b). f =6: From Figure 5(b), it can be seen that the forward 4 Applied Bionics and Biomechanics BB BF HB HF Hose straight connection Rapid-plug joint Infusion hose (a) Lubricating hole design (b) Physical drawing Figure 3: Coupling bionic specimen. 12 11 10 9 8 7 6 5 4 3 2 1 (a) Structure diagram of the test equipment (b) Testing procedure Figure 4: Test and equipment. 1: data acquisition device, 2: support frame, 3: soil bin, 4: force sensor, 5: bionic sample, 6: peristaltic pump, 7: lubricating adjustment device, 8: water tank, 9: moving plate, 10: motion control device, 11: screw drive set, 12: pulley block. Table 2: Single factor test scheme. s = 〠ðÞ y − y =0:93, i0 0 Factors i=1 ð5Þ Level Forward velocity Flow rate of lubricating Normal f =2, (cm/min) fluid (ml/s) pressure (N) 1 100 0.01 17 2 200 0.02 34 s = 〠 y − y =0:93, ðÞ e i0 0 3 300 0.03 51 ð6Þ i=1 4 400 0.04 68 f =4: lf 5 500 0.05 85 So Because s /f 回 回 F = =51:83 > F 6, 6 =8:47, ð7Þ ðÞ ! 回 s /f 13 17 R R S = 〠 y − 〠 y = 293:24, i i i=1 i=1 ð3Þ s /f lf lf F = =2:97 < F 4, 2 =3:23: ð8Þ ðÞ lf 0:25 f = 12, s /f e e The statistical test results show that the significant level of the equation is 0.01 and the fitting is very good, which can be s = s − s =5:55, R 回 considered as the best regression equation. The central pro- ð4Þ f =6, R cessing and coding formula of the factors in the table are Applied Bionics and Biomechanics 5 100 200 300 400 500 17 34 51 68 85 Forward velocity (cm/min) Normal pressure (N) Lubrication Lubrication Without lubrication Without lubrication (a) The effect of forward velocity on forward resistance (b) The effect of normal pressure on forward resistance 0.02 0.04 0.06 0.08 0.1 Flow rate of lubricating fluid (ml/s) (c) The effect of flow rate of lubricating fluid on forward resistance Figure 5: Results of a single factor test. Table 3: Natural factor level and its coding table. x z Z (N) Z (ml/s) Z (cm/min) j j 1 2 3 51 0.1 500 1 46.56 0.09 447.82 0 34 0.06 300 1 21.44 0.03 152.18 -r 17 0.02 100 z − z 2j 1j Δ = 12.56 0.03 147.82 2r z − z j 0j x = x =0:076 ×ðÞ z − 34 x =33:33 ×ðÞ z − 0:06 x =0:006 ×ðÞ z − 300 1 1 2 1 3 1 Note: Z means normal pressure; Z means flow rate of lubricating fluid; Z means forward velocity. 1 2 3 put into equation (1) and the regression equation is obtained cating fluid>forward velocity, and the three factors have a as follows: significant effect on the forward resistance. From formula (9), we can see that normal pressure Z , flow rate of lubricating fluid Z , and forward velocity Z have 2 3 y =12:21 + 0:2z + 100:98z − 0:0028z 1 2 3 a secondary effect on the forward resistance, but there is no ð9Þ 2 2 −6 2 +0:0093z − 1066:45z +8:28 × 10 z : interaction between them, as shown in Figure 6. 1 2 3 By testing the regression coefficient of formula (1), it is 4. Conclusion found that the order of the test factors affecting the forward resistance is as follows: normal pressure>flow rate of lubri- We can conclude the following: Forward resistance (N) Forward resistance (N) Forward resistance (N) Forward velocity (cm/min) Forward velocity (cm/min) Normal pressure (N) 6 Applied Bionics and Biomechanics Table 4: Orthogonal rotation combination test plan and results. 2 2 2 X X z X z X z Y ðÞ ðÞ ðÞ ′ ′ ′ X X X X X X 0 1 1 2 2 3 3 i 1 1 2 2 3 3 1 1 1 1 1 1 1 1 20.09 2 1 1 -1 -1 1 1 1 22.64 3 1 -1 1 -1 1 1 1 9.84 4 1 -1 -1 1 1 1 1 10.14 51 01 r 0 0 26.96 61 -r 00 r 0 0 11.6 r r 71 0 00 0 13.65 -r 81 0 00 r 0 16.18 r r 91 0 0 00 13.53 -r 10 1 0 0 00 r 18.78 11 1 0 0 0 0 0 0 15.35 12 1 0 0 0 0 0 0 15.21 13 1 0 0 0 0 0 0 15.39 j 13 7.66 7.66 7.66 6.19 6.19 6.19 j 209.36 43.53 -6.27 -9.95 10 -5.98 -1.44 16.10 5.68 -0.81 -1.29 1.61 -0.96 -0.23 3371.66 247.37 5.13 12.92 16.16 5.78 0.33 27701.11 574.72 1447.32 1809.08 646.93 37.51 0.01 0.01 0.01 0.01 0.01 0.05 21.5 20.5 19.5 18.5 0.01 400 0.05 0.02 0.04 100 0.03 0.03 80 200 60 0.04 0.02 100 0.01 0.05 (a) Z =17N (b) Z =0:05 ml/s 1 2 400 100 100 0 (c) Z = 100 N Figure 6: Results of orthogonal rotation combination test. Normal pressure (N) Flow rate of lubricating fluid (ml/s) Flow rate of lubricating fluid (ml/s) Forward resistance (N) Forward resistance (N) Forward resistance (N) Applied Bionics and Biomechanics 7 (1) Based on the reverse engineering method, earthworm References corrugated curves are extracted; bionic samples [1] L. Q. Ren, D. X. Chen, and B. C. Chen, “A summary of study matched with real earthworm’s body surface are on soil adhesion,” Transactions of the CSAE, vol. 6, no. 1, designed. The bionic sample was printed by 3D print- pp. 1–7, 1990. ing, the location of lubricating hole was determined [2] L. Q. Ren, J. Tong, J. Q. Li, and B. C. Chen, “Biomimetics of by the experiment method, and the bionic coupling machinery for soft terrain,” Transactions of the Chinese Society of corrugated self-lubrication was realized for Agricultural Machinery, vol. 31, no. 1, pp. 5–9, 2000. (2) A test rig was designed and developed to test the [3] L. Q. Ren, “The progress of the research on terrain-machine lubricating drag reduction performance of soil- bionics of reducing soil adhesion,” Science in China Series E: Technological Sciences, vol. 38, pp. 1353–1364, 2008. engaging components, which can accurately control the flow rate of lubricating fluid and measure the [4] L. Q. Ren, J. Tong, J. Q. Li, and B. C. Chen, “Soil adhesion and forward resistance of the sample quickly biomimetics of soil-engaging components: a review,” Journal of Agricultural Engineering Research, vol. 79, no. 3, pp. 239– (3) The results of a single factor test show that the drag 263, 2001. reduction of the bionic coupling sample is obvious, [5] T. Shelley, “Lubrication-Worms show way to efficiently move- the drag reduction rate is 22.65%-34.89%, and the Tom Shelley reports on an animal-inspired way to improve the forward resistance decreases with the increase of for- efficiency of agricultural equipment,” Eureka-Innovative Engi- ward velocity, which is proportional to the normal neering Design, vol. 24, no. 1, pp. 28-29, 2004. pressure, and at the same time, when the flow rate [6] Y. Lu, “Significance and progress of bionics,” Journal of Bionic of lubricating fluid increases gradually, the forward Engineering, vol. 1, no. 1, pp. 1–3, 2004. resistance decreases first and then tends to stabilize [7] A. Q. Li, L. Q. Ren, B. C. Chen, and X. X. Cui, “Constitution and mechanism analysis of reducing soil adhesion for the body (4) The regression equations between forward resistance surface liquid of earthworms,” Transactions of The Chinese and normal pressure, flow rate of lubricating fluid, Society of Agricultural Engineering, vol. 6, no. 3, pp. 8–14, and the forward velocity of the bionic coupling sam- ple were obtained by using the ternary quadratic [8] J. R. Sun, B. N. Sun, J. H. Wei et al., “Measurement and deter- regression combination test. The regression analysis mination earthworm skin potential related to moving,” Jour- shows that the three factors have secondary effects nal of Jilin University of Technology, vol. 21, no. 4, pp. 18–24, on the forward resistance, and the order is as follows: normal pressure>flow rate of lubricating fluid>for- [9] L. Q. Ren, Q. Cong, L. K. Wu, and D. X. Chen, “Study on the ward velocity, but there was no interaction between reduction of soil adhesion and resistance by the application them of non smooth surface electroosmosis,” Transactions of The Chinese Society of Agricultural Engineering, vol. 11, no. 3, pp. 24–28, 1995. Data Availability [10] Q. Cong, L. K. Wu, L. Q. Ren, and B. Chen, “The principled experiment of reducing soil adhesion and scouring soil by We have submitted the raw data used in our manuscript and nonsmooth surface electroosmosis,” Transactions of the the other supplementary date are shown in the attachment. Chinese Society of Agricultural Engineering, vol. 11, no. 3, Other researchers can access the data supporting the conclu- pp. 19–23, 1995. sions of the study. (1) The nature of the data is the source [11] L. Q. Ren, Y. P. Wang, J. Q. Li, and S. Sun, “Bionic research on data of the image in the paper; (2) the data can be accessed flexible nonsmooth surface of typical animals,” Transactions of on the submitting system or through email to zoumeng@j- the Chinese Society of Agricultural Engineering, vol. 12, no. 4, lu.edu.cn; (3) there are no restrictions on the data access. pp. 31–36, 1996. [12] Z. J. Zhao, Bionic study on the mechanism of reducing adhesion and desorption of earthworms, Peking University, Beijing, Disclosure [13] J. R. Sun and Z. D. Dai, “Non-smooth surface bionics(II),” The results were originally presented at ICBE2019. Journal Advances in Natural Sciences, vol. 18, no. 7, pp. 727– 733, 2008. [14] G. M. Liu, J. Q. Li, X. M. Tian, M. Zou, and Y. Li, “Experiment Conflicts of Interest on reduction of soil adhesion force and sliding resistance of earthworm non-smooth surface,” Transactions of the Chinese No potential conflict of interest was reported by the authors. Society for Agricultural Machinery, vol. 39, no. 9, pp. 138– 143, 2008. [15] J. Q. Li, B. X. Kou, G. M. Liu, W. Fan, and L. Liu, “Resistance Acknowledgments reduction by bionic coupling of the earthworm lubrication This project is supported by the National Natural Science function,” Science China Technological Sciences, vol. 53, Foundation of China Youth Science Foundation (Grant No. no. 11, pp. 2989–2995, 2010. 5140051354). The project is also supported from China [16] W. P. Shi, L. Q. Ren, and Y. Y. Yan, “The creeping mechanism Scholarship Council (CSC) for the first author’s scholarship. of the non-smooth wavy surface of earthworm body,” Chinese 8 Applied Bionics and Biomechanics Journal of Mechanics and Engineering, vol. 27, no. 3, pp. 73-74, [17] Y. Q. Zu and Y. Y. Yan, “Numerical simulation of electro- osmotic flow near earthworm surface,” Journal of Bionic Engineering, vol. 3, no. 4, pp. 179–186, 2006. [18] Y. Y. Yan, Y. Q. Zu, L. Q. Ren, and J. Q. Li, “Numerical modeling of electro-osmotically driven flow within the microthin liquid layer near an earthworm surface-a biomi- metic approach,” Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, vol. 221, pp. 1201–1209, 2007. [19] Y. Zhang, C. H. Zhou, and L. Q. Ren, “Biology coupling char- acteristics on soil-engaging components of mole crickets,” Journal of Bionic Engineering, vol. 5, Suppl 1, pp. 164–171, [20] L. Q. Ren and Y. H. Liang, “Biological couplings: classification and characteristic rules,” Science in China Series E: Technolog- ical Sciences, vol. 40, no. 1, pp. 5–13, 2010. [21] L. H. Shu, K. Ueda, and I. Chiu, “Biologically inspired design,” CIRP Annals - Manufacturing Technology, vol. 60, pp. 673– 693, 2011. [22] D. Zhang, Y. Chen, Y. Ma, G. Li, J. Sun, and J. Tong, “Earth- worm epidermal mucus: rheological behavior reveals drag- reducing characteristics in soil,” Soil and Tillage Research, vol. 158, pp. 57–66, 2016. [23] Y. Q. Gu, T. X. Fan, J. G. Mou, L. F. Jiang, D. H. Wu, and S. H. Zheng, “A review of bionic technology for drag reduction based on analysis of abilities the earthworm,” International Journal of Engineering Research in Africa, vol. 19, pp. 103– 111, 2016. [24] G. M. Liu, Coupling bionic research on the adhesion and resis- tance reduction of the earthworm surface, Jilin University, Changchun, China, 2009. [25] Y. Q. Gu, J. G. Mou, D. S. Dai et al., “Characteristics on drag reduction of bionic jet surface based on earthworm’s back ori- fice jet,” Acta Physica Sinica, vol. 64, no. 2, pp. 306–315, 2015. [26] Y. Gu, J. Mu, S. Zheng, G. Zhao, J. Ru, and C. G. Wang, “Effect of jet hole arrangement on drag reduction characteristics of jet surface,” Transactions of the Chinese Society for Agricultural Machinery, vol. 45, no. 10, pp. 340–346, 2014. [27] L. Q. Ren, Optimum design and analysis of experiments, L. Ren, Ed., Higher Education Press, Beijing, 2003. International Journal of Advances in Rotating Machinery Multimedia Journal of The Scientific Journal of Engineering World Journal Sensors Hindawi Hindawi Publishing Corporation Hindawi Hindawi Hindawi Hindawi www.hindawi.com Volume 2018 http://www www.hindawi.com .hindawi.com V Volume 2018 olume 2013 www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 Journal of Control Science and Engineering Advances in Civil Engineering Hindawi Hindawi www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 Submit your manuscripts at www.hindawi.com Journal of Journal of Electrical and Computer Robotics Engineering Hindawi Hindawi www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 VLSI Design Advances in OptoElectronics International Journal of Modelling & Aerospace International Journal of Simulation Navigation and in Engineering Engineering Observation Hindawi Hindawi Hindawi Hindawi Volume 2018 Volume 2018 Hindawi www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 www.hindawi.com www.hindawi.com www.hindawi.com Volume 2018 International Journal of Active and Passive International Journal of Antennas and Advances in Chemical Engineering Propagation Electronic Components Shock and Vibration Acoustics and Vibration Hindawi Hindawi Hindawi Hindawi Hindawi www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Applied Bionics and Biomechanics Hindawi Publishing Corporation

Experimental Study on Drag Reduction Characteristics of Bionic Earthworm Self-Lubrication Surface

Loading next page...
 
/lp/hindawi-publishing-corporation/experimental-study-on-drag-reduction-characteristics-of-bionic-XTUA6eLCMz
Publisher
Hindawi Publishing Corporation
Copyright
Copyright © 2019 Guomin Liu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
ISSN
1176-2322
eISSN
1754-2103
DOI
10.1155/2019/4984756
Publisher site
See Article on Publisher Site

Abstract

Hindawi Applied Bionics and Biomechanics Volume 2019, Article ID 4984756, 8 pages https://doi.org/10.1155/2019/4984756 Research Article Experimental Study on Drag Reduction Characteristics of Bionic Earthworm Self-Lubrication Surface 1,2 3 3 2 3 Guomin Liu, Xueqiao Wu, Meng Zou , Yuying Yan, and Jianqiao Li College of Civil Engineering, Jilin Jianzhu University, Changchun 130118, China Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, UK Key Laboratory of Bionic Engineering, Jilin University, Changchun 130022, China Correspondence should be addressed to Meng Zou; zoumeng@jlu.edu.cn Received 24 June 2019; Accepted 20 September 2019; Published 23 October 2019 Academic Editor: Raimondo Penta Copyright © 2019 Guomin Liu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. In the present study, a coupling bionic method is used to study the drag reduction characteristics of corrugated surface with lubrication. In order to test the drag reduction features, bionic specimen was prepared inspired by earthworm surface and lubrication. Based on the reverse engineering method, nonsmooth curve of earthworm surface was extracted and the bionic corrugated sample was designed, and the position of lubrication hole was established by experimental testing. The lubricating drag reduction performance, the influence of normal pressure, the forward velocity, and the flow rate of lubricating fluid on the forward resistance of the bionic specimens were analyzed through a single factor test by using the self-developed test equipment. The model between the forward resistance and the three factors was established through the ternary quadratic regression test. The results show that the drag reduction effect is obvious, the drag reduction rate is 22.65% to 34.89%, and the forward resistance decreases with the increase of the forward velocity, increases with the increase of the normal pressure, and decreases first and then becomes stable with the increase of flow rate of lubricating fluid. There are secondary effects on forward resistance by the three factors, and the influencing order is as follows: normal pressure>flow rate of lubricating fluid>forward velocity. [9, 10] put forward the surface electroosmosis technology 1. Introduction according to the phenomenon of earthworm surface electro- Soil adhesion is a major problem in the field of ground trans- osmosis and applied it to soil-engaging components. In the portation, excavation, and farming machinery. The adhesion late 1990s, Ren et al. [11] studied the surface flexibility of of soil to soil-engaging components will seriously affect the earthworms and their antiviscosity characteristics. After 2004, Sun et al. [12, 13] and Li et al. [14–16] have successively working efficiency and quality of ground machinery, thus increasing energy consumption [1–4]. With the aggravation carried out biomimetic research on the viscosity reduction of energy and environmental crises, it is imperative to design and drag reduction of earthworm’s nonsmooth surface. Shi and produce soil-engaging components with high efficiency et al. [17] carried out a biomimetic study on earthworm and low consumption. Earthworm is a typical soil animal, telescopic motion. Zu and Yan [18, 19] used the lattice which has an excellent function of reducing drag and remov- Boltzmann method to simulate the surface electroosmosis ing soil in long-term evolution. It can also move freely in of earthworms and further studied the adhesion reducing clayey soil and does not have clay [5, 6]. Since early 1990s, the mechanism of earthworm surface electroosmosis. These scholars at home and abroad have gradually carried out studies mainly focus on the unit biomimetic of a certain bionic research on reducing soil adhesion and scouring soil aspect or a certain factor. of earthworm. Li et al. [7] carried out the extraction of earth- With the deepening of bionic research, researchers have worm surface fluid and studied the adhesion reducing the found that the functions, which biologically adapt to the mechanism of earthworm surface self-lubrication. Sun et al. external environment, are not only the role of a single factor [8] measured the surface potential of earthworms; Ren et al. or the simple addition of multiple factors but also the results 2 Applied Bionics and Biomechanics selecting the yellow clay of Changchun city, when the soil of synergistic action that a variety of interdependent, mutually affecting factors are coupled through a certain mechanism moisture content was 22.2% and the forward velocity was [20, 21]. The research shows that earthworm has an excellent 200 cm/min, the experiment was carried out with five differ- ent normal pressure conditions, and each group was repeated function of viscosity reduction and drag reduction, which is the result of multifactor coupling action such as body surface three times. As shown in Figure 2, the adhesion was at a nor- structure, body surface flexibility, body surface electroosmo- mal pressure of 34 N. sis, body surface lubrication, and its unique movement mode The adhesion data is shown in Table 1. According to [22–25]. Based on the nonsmooth structure and the self- Table 1, there is more adhesion to the head and body, but there is no adhesion in the tail. lubricating characteristics of earthworm surface, this paper discusses the drag reduction characteristics of earthworm In order to prevent clogging, the bionic dorsal foramen by a dual-coupling biomimetic method, in order to provide was designed in the top of the sulcus of the head and body a new theory and method for the design of soil-engaging backward-forward direction according to the adhesion and components with high efficiency and low consumption. model characteristics. They are including the anterior fora- men of the head (HF), the posterior foramen of the head (HB), the anterior foramen of the body (BF), and the poste- 2. Materials and Methods rior foramen of the body (BB), as shown in Figure 3. 2.1. Coupling Bionic Sample Design. Earthworms are com- mon animals that can move freely in the soil; it can adapt 2.2. Test Rig and Methods. According to the test require- ments, the test rig for lubricating and drag reduction perfor- to different soil environments. The viscosity reduction ability of earthworms mainly depends on its flexible nonsmooth mance of soil-engaging components was designed, as shown in Figure 4(a). The rig consists of support frame, soil bin, body surface, bioelectroosmotic system, surface lubrication, corrugated body surface, and other factors [12]. In this paper, motion control device, data acquisition device, and lubrica- Eisenia foetida was used as bionic prototype, and according tion adjustment device. The soil is fixed on the support frame, and the motion to the previous studies, the corrugated body surface of earth- worm has the characteristics of reducing viscosity and drag control device is fixed directly above the soil bin, mainly [21]. The effect of viscosity and drag reduction of the differ- including servomotor, pulley motion pair, and sliding plate, which is responsible for the bidirectional motion of the ent states of the body from large to small is contraction state, motionlessness state, and stretched state, and the effect of soil-engaging components in the soil bin. The lubrication adjustment device is fixed on the upper left side of the soil viscosity and drag reduction of the head is more obvious than that of the body. Therefore, the head contraction state of bin, mainly including peristaltic pump, peristaltic pump earthworm has the best viscosity and drag reduction effect frame, and water tank, which can convey lubricating fluid during the movement of soil-engaging components. The [14, 15], as shown in Figure 1(a). Based on the reverse engineering method, the corrugated pump is compiled by external software and connected to the computer. According to the conditions, the flow rate body surface of earthworm was scanned by a 3D laser scan- ner, and the data of point cloud was processed by Geomagic can be set and the number of the opening pump and the software. There are about ten knots involved in each lubricating position can also be set, so that the flow rate can be accurately adjusted. The data acquisition device is fixed extension-contraction movement of earthworms, the head and body are the main position of soil adhesion and force, at the top of the soil bin, including computer, object board, and angle steel, which is responsible for collecting data and and the tail are weak [14–16], so they are equivalent to a cyl- inder when designing biomimetic samples, composed of 10 controlling each device compiled by software. body knots, and the tail curve is designed as the symmetrical After the equipment connection is completed, the bionic sample is placed in the soil bin and the moving speed, the curve of the head. Through the commands of three-point arc, tangent arc, and curve curvature extension in CAXA, the flow rate, and the number and position of the peristaltic pump are set up by the control software, and then the motor smooth curve which is close to the contour curve of the cor- rugated body surface of earthworm is drawn, and the coor- is started. The lead screw moves the bionic sample forward, dinate point data of the smooth curve are extracted. Then, and the data acquisition is transmitted to the computer by the data collector in actual time. The force sensor is Kistler the spline curves of the head shape are drawn by using coor- dinate points. At last, amplifying the size by six times for Triaxial Force Sensor Type 9027C and assembly located and fixed between the traction rope and moving plate. The engineering needs, the biomimetic sample was printed in 3D. As shown in Figure 1(b), the length is 207.18 mm, the test image and the data can be obtained by software. For width is 62.59 mm, the thickness is 31.28 mm, the sample the testing procedure, see Figure 4(b). material is photosensitive resin, and the printing precision is 0.1 mm. For comparative analysis, a smooth specimen of 3. Test and Result Analysis the same size was designed, as shown in Figure 1(c). The lubrication hole’s position of earthworm surface has 3.1. Single Factor Test and Result Analysis. Forward velocity, direct influence on the lubricating effect [26], and the hole flow rate of lubricating fluid, and normal pressure are impor- location of the corrugated surface sample is determined by tant factors affecting forward resistance. In order to investi- the test method. According to previous studies, normal pres- gate their effects, a single factor test was carried out when sure is the most important factor affecting adhesion force. So, soil moisture content was 22.2% with lubrication and Applied Bionics and Biomechanics 3 31.28 mm 4.7 mm 54.24 m 98.7 mm 54.24 m 0.44 mm Unit size Head Body Tail (a) Surface specimen of earthworm (b) Bionic specimen (c) Smooth contrast specimen Figure 1: Specimen. resistance is 18.01 N~70.08 N without lubrication and 11.23 N~48.47 N with lubrication, and the drag reduction rate is 36.27%~58.46%. With the increase of normal pressure, the reducing effect is more and more obvious, and the for- ward resistance of unlubricated and lubricated conditions will increase continuously, because the contact area between corrugated surface and soil increases with the increase of nor- mal pressure, and the gap between corrugated surface and soil decreases, which make soil compacted and the friction resistance increased. Figure 2: Adhesion when normal pressure was 34 N. When the normal pressure is 34 N and the forward velocity is 300 cm/min, the effect of the flow rate of lubricat- Table 1: Adhesive quality of different parts. ing fluid on the forward resistance is shown in Figure 5(c). From Figure 5(c), it can be seen that the forward resistance Head Body Tail Total Normal decreases first and then remains unchanged with the increase adhesion adhesion adhesion adhesion pressure (N) of the flow rate of the lubricating fluid. When the velocity rate (g) (g) (g) (g) is 0.08 ml/s, the forward resistance is 21.32 N that is close to 17 7.4 6.53 0.29 14.22 20.09 N when the rate is 0.1 ml/s. This is because with the 34 13.83 6.95 0.09 20.87 increase of the flow rate of the lubricating fluid, the fluid fully 51 16.21 9.58 0.22 26.01 permeates into the contact interface between corrugated sur- 68 19.36 13.17 0.46 32.99 face and soil and then forms the interfacial lubrication, mak- 85 28.02 14.44 0.12 42.58 ing the resistance decrease. When it increases to a certain condition, the interface water film is saturated, so the forward resistance is almost unchanged. nonlubrication, and three repeated tests were carried out to 3.2. Ternary Quadratic Regression Combination Test and reduce the error. The test plan is shown in Table 2. Result Analysis. In order to further explore the effect of these The effect of forward velocity on forward resistance three factors and establish the equation between forward is shown in Figure 5(a) when the normal pressure is 34 N resistance and each factor, the three-element quadratic and the flow rate of lubricating fluid is 0.06 ml/s. From Figure 5(a), it can be seen that the forward resistance regression combination test [27] was carried out, and the repeated test with m is between 26.32 N~33.14 N without lubrication and =3, r =1:831 was selected. The factor 18.11 N~23.46 N with lubrication, and the drag reduction level and coding are shown in Table 3. According to the testing requirements and the designing rate is 24.19% to 33.71%. In addition, the forward resistance decreases with the increase of the forward speed under both principle of quadratic regression orthogonal, the experimen- lubricated and nonlubricated conditions. Without lubrica- tal scheme is worked out and the regression coefficients and tion, it decreases obviously with the increase of velocity, squares of each sequence are calculated as shown in Table 4. because when the velocity is small, the contact time between By testing the regression coefficient, the equation is obtained as follows: corrugated body surface and soil becomes longer and the dis- turbance to the soil increases in the course of movement. With lubrication, the forward resistance of 500 cm/min is ̂y =16:10 + 5:68x − 0:81x − 1:29x 1 2 3 ð1Þ greater than that of 400 cm/min, which is due to that the fluid 2 2 2 +1:61x − 0:96x − 0:23x : 1 2 3 cannot penetrate the interface between corrugated surface and soil sufficiently with the increase of velocity, resulting Therefore, the sum of regressing squares is in a reduced lubrication effect. When the forward velocity is 300 cm/min, and the flow rate of lubricating fluid is 0.06ml/s, the effect of normal S = S + S + S + S + S + S = 287:69, 回 x x x ′ ′ ′ x x x 1 2 3 1 2 3 ð2Þ pressure on the forward resistance is shown in Figure 5(b). f =6: From Figure 5(b), it can be seen that the forward 4 Applied Bionics and Biomechanics BB BF HB HF Hose straight connection Rapid-plug joint Infusion hose (a) Lubricating hole design (b) Physical drawing Figure 3: Coupling bionic specimen. 12 11 10 9 8 7 6 5 4 3 2 1 (a) Structure diagram of the test equipment (b) Testing procedure Figure 4: Test and equipment. 1: data acquisition device, 2: support frame, 3: soil bin, 4: force sensor, 5: bionic sample, 6: peristaltic pump, 7: lubricating adjustment device, 8: water tank, 9: moving plate, 10: motion control device, 11: screw drive set, 12: pulley block. Table 2: Single factor test scheme. s = 〠ðÞ y − y =0:93, i0 0 Factors i=1 ð5Þ Level Forward velocity Flow rate of lubricating Normal f =2, (cm/min) fluid (ml/s) pressure (N) 1 100 0.01 17 2 200 0.02 34 s = 〠 y − y =0:93, ðÞ e i0 0 3 300 0.03 51 ð6Þ i=1 4 400 0.04 68 f =4: lf 5 500 0.05 85 So Because s /f 回 回 F = =51:83 > F 6, 6 =8:47, ð7Þ ðÞ ! 回 s /f 13 17 R R S = 〠 y − 〠 y = 293:24, i i i=1 i=1 ð3Þ s /f lf lf F = =2:97 < F 4, 2 =3:23: ð8Þ ðÞ lf 0:25 f = 12, s /f e e The statistical test results show that the significant level of the equation is 0.01 and the fitting is very good, which can be s = s − s =5:55, R 回 considered as the best regression equation. The central pro- ð4Þ f =6, R cessing and coding formula of the factors in the table are Applied Bionics and Biomechanics 5 100 200 300 400 500 17 34 51 68 85 Forward velocity (cm/min) Normal pressure (N) Lubrication Lubrication Without lubrication Without lubrication (a) The effect of forward velocity on forward resistance (b) The effect of normal pressure on forward resistance 0.02 0.04 0.06 0.08 0.1 Flow rate of lubricating fluid (ml/s) (c) The effect of flow rate of lubricating fluid on forward resistance Figure 5: Results of a single factor test. Table 3: Natural factor level and its coding table. x z Z (N) Z (ml/s) Z (cm/min) j j 1 2 3 51 0.1 500 1 46.56 0.09 447.82 0 34 0.06 300 1 21.44 0.03 152.18 -r 17 0.02 100 z − z 2j 1j Δ = 12.56 0.03 147.82 2r z − z j 0j x = x =0:076 ×ðÞ z − 34 x =33:33 ×ðÞ z − 0:06 x =0:006 ×ðÞ z − 300 1 1 2 1 3 1 Note: Z means normal pressure; Z means flow rate of lubricating fluid; Z means forward velocity. 1 2 3 put into equation (1) and the regression equation is obtained cating fluid>forward velocity, and the three factors have a as follows: significant effect on the forward resistance. From formula (9), we can see that normal pressure Z , flow rate of lubricating fluid Z , and forward velocity Z have 2 3 y =12:21 + 0:2z + 100:98z − 0:0028z 1 2 3 a secondary effect on the forward resistance, but there is no ð9Þ 2 2 −6 2 +0:0093z − 1066:45z +8:28 × 10 z : interaction between them, as shown in Figure 6. 1 2 3 By testing the regression coefficient of formula (1), it is 4. Conclusion found that the order of the test factors affecting the forward resistance is as follows: normal pressure>flow rate of lubri- We can conclude the following: Forward resistance (N) Forward resistance (N) Forward resistance (N) Forward velocity (cm/min) Forward velocity (cm/min) Normal pressure (N) 6 Applied Bionics and Biomechanics Table 4: Orthogonal rotation combination test plan and results. 2 2 2 X X z X z X z Y ðÞ ðÞ ðÞ ′ ′ ′ X X X X X X 0 1 1 2 2 3 3 i 1 1 2 2 3 3 1 1 1 1 1 1 1 1 20.09 2 1 1 -1 -1 1 1 1 22.64 3 1 -1 1 -1 1 1 1 9.84 4 1 -1 -1 1 1 1 1 10.14 51 01 r 0 0 26.96 61 -r 00 r 0 0 11.6 r r 71 0 00 0 13.65 -r 81 0 00 r 0 16.18 r r 91 0 0 00 13.53 -r 10 1 0 0 00 r 18.78 11 1 0 0 0 0 0 0 15.35 12 1 0 0 0 0 0 0 15.21 13 1 0 0 0 0 0 0 15.39 j 13 7.66 7.66 7.66 6.19 6.19 6.19 j 209.36 43.53 -6.27 -9.95 10 -5.98 -1.44 16.10 5.68 -0.81 -1.29 1.61 -0.96 -0.23 3371.66 247.37 5.13 12.92 16.16 5.78 0.33 27701.11 574.72 1447.32 1809.08 646.93 37.51 0.01 0.01 0.01 0.01 0.01 0.05 21.5 20.5 19.5 18.5 0.01 400 0.05 0.02 0.04 100 0.03 0.03 80 200 60 0.04 0.02 100 0.01 0.05 (a) Z =17N (b) Z =0:05 ml/s 1 2 400 100 100 0 (c) Z = 100 N Figure 6: Results of orthogonal rotation combination test. Normal pressure (N) Flow rate of lubricating fluid (ml/s) Flow rate of lubricating fluid (ml/s) Forward resistance (N) Forward resistance (N) Forward resistance (N) Applied Bionics and Biomechanics 7 (1) Based on the reverse engineering method, earthworm References corrugated curves are extracted; bionic samples [1] L. Q. Ren, D. X. Chen, and B. C. Chen, “A summary of study matched with real earthworm’s body surface are on soil adhesion,” Transactions of the CSAE, vol. 6, no. 1, designed. The bionic sample was printed by 3D print- pp. 1–7, 1990. ing, the location of lubricating hole was determined [2] L. Q. Ren, J. Tong, J. Q. Li, and B. C. Chen, “Biomimetics of by the experiment method, and the bionic coupling machinery for soft terrain,” Transactions of the Chinese Society of corrugated self-lubrication was realized for Agricultural Machinery, vol. 31, no. 1, pp. 5–9, 2000. (2) A test rig was designed and developed to test the [3] L. Q. Ren, “The progress of the research on terrain-machine lubricating drag reduction performance of soil- bionics of reducing soil adhesion,” Science in China Series E: Technological Sciences, vol. 38, pp. 1353–1364, 2008. engaging components, which can accurately control the flow rate of lubricating fluid and measure the [4] L. Q. Ren, J. Tong, J. Q. Li, and B. C. Chen, “Soil adhesion and forward resistance of the sample quickly biomimetics of soil-engaging components: a review,” Journal of Agricultural Engineering Research, vol. 79, no. 3, pp. 239– (3) The results of a single factor test show that the drag 263, 2001. reduction of the bionic coupling sample is obvious, [5] T. Shelley, “Lubrication-Worms show way to efficiently move- the drag reduction rate is 22.65%-34.89%, and the Tom Shelley reports on an animal-inspired way to improve the forward resistance decreases with the increase of for- efficiency of agricultural equipment,” Eureka-Innovative Engi- ward velocity, which is proportional to the normal neering Design, vol. 24, no. 1, pp. 28-29, 2004. pressure, and at the same time, when the flow rate [6] Y. Lu, “Significance and progress of bionics,” Journal of Bionic of lubricating fluid increases gradually, the forward Engineering, vol. 1, no. 1, pp. 1–3, 2004. resistance decreases first and then tends to stabilize [7] A. Q. Li, L. Q. Ren, B. C. Chen, and X. X. Cui, “Constitution and mechanism analysis of reducing soil adhesion for the body (4) The regression equations between forward resistance surface liquid of earthworms,” Transactions of The Chinese and normal pressure, flow rate of lubricating fluid, Society of Agricultural Engineering, vol. 6, no. 3, pp. 8–14, and the forward velocity of the bionic coupling sam- ple were obtained by using the ternary quadratic [8] J. R. Sun, B. N. Sun, J. H. Wei et al., “Measurement and deter- regression combination test. The regression analysis mination earthworm skin potential related to moving,” Jour- shows that the three factors have secondary effects nal of Jilin University of Technology, vol. 21, no. 4, pp. 18–24, on the forward resistance, and the order is as follows: normal pressure>flow rate of lubricating fluid>for- [9] L. Q. Ren, Q. Cong, L. K. Wu, and D. X. Chen, “Study on the ward velocity, but there was no interaction between reduction of soil adhesion and resistance by the application them of non smooth surface electroosmosis,” Transactions of The Chinese Society of Agricultural Engineering, vol. 11, no. 3, pp. 24–28, 1995. Data Availability [10] Q. Cong, L. K. Wu, L. Q. Ren, and B. Chen, “The principled experiment of reducing soil adhesion and scouring soil by We have submitted the raw data used in our manuscript and nonsmooth surface electroosmosis,” Transactions of the the other supplementary date are shown in the attachment. Chinese Society of Agricultural Engineering, vol. 11, no. 3, Other researchers can access the data supporting the conclu- pp. 19–23, 1995. sions of the study. (1) The nature of the data is the source [11] L. Q. Ren, Y. P. Wang, J. Q. Li, and S. Sun, “Bionic research on data of the image in the paper; (2) the data can be accessed flexible nonsmooth surface of typical animals,” Transactions of on the submitting system or through email to zoumeng@j- the Chinese Society of Agricultural Engineering, vol. 12, no. 4, lu.edu.cn; (3) there are no restrictions on the data access. pp. 31–36, 1996. [12] Z. J. Zhao, Bionic study on the mechanism of reducing adhesion and desorption of earthworms, Peking University, Beijing, Disclosure [13] J. R. Sun and Z. D. Dai, “Non-smooth surface bionics(II),” The results were originally presented at ICBE2019. Journal Advances in Natural Sciences, vol. 18, no. 7, pp. 727– 733, 2008. [14] G. M. Liu, J. Q. Li, X. M. Tian, M. Zou, and Y. Li, “Experiment Conflicts of Interest on reduction of soil adhesion force and sliding resistance of earthworm non-smooth surface,” Transactions of the Chinese No potential conflict of interest was reported by the authors. Society for Agricultural Machinery, vol. 39, no. 9, pp. 138– 143, 2008. [15] J. Q. Li, B. X. Kou, G. M. Liu, W. Fan, and L. Liu, “Resistance Acknowledgments reduction by bionic coupling of the earthworm lubrication This project is supported by the National Natural Science function,” Science China Technological Sciences, vol. 53, Foundation of China Youth Science Foundation (Grant No. no. 11, pp. 2989–2995, 2010. 5140051354). The project is also supported from China [16] W. P. Shi, L. Q. Ren, and Y. Y. Yan, “The creeping mechanism Scholarship Council (CSC) for the first author’s scholarship. of the non-smooth wavy surface of earthworm body,” Chinese 8 Applied Bionics and Biomechanics Journal of Mechanics and Engineering, vol. 27, no. 3, pp. 73-74, [17] Y. Q. Zu and Y. Y. Yan, “Numerical simulation of electro- osmotic flow near earthworm surface,” Journal of Bionic Engineering, vol. 3, no. 4, pp. 179–186, 2006. [18] Y. Y. Yan, Y. Q. Zu, L. Q. Ren, and J. Q. Li, “Numerical modeling of electro-osmotically driven flow within the microthin liquid layer near an earthworm surface-a biomi- metic approach,” Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, vol. 221, pp. 1201–1209, 2007. [19] Y. Zhang, C. H. Zhou, and L. Q. Ren, “Biology coupling char- acteristics on soil-engaging components of mole crickets,” Journal of Bionic Engineering, vol. 5, Suppl 1, pp. 164–171, [20] L. Q. Ren and Y. H. Liang, “Biological couplings: classification and characteristic rules,” Science in China Series E: Technolog- ical Sciences, vol. 40, no. 1, pp. 5–13, 2010. [21] L. H. Shu, K. Ueda, and I. Chiu, “Biologically inspired design,” CIRP Annals - Manufacturing Technology, vol. 60, pp. 673– 693, 2011. [22] D. Zhang, Y. Chen, Y. Ma, G. Li, J. Sun, and J. Tong, “Earth- worm epidermal mucus: rheological behavior reveals drag- reducing characteristics in soil,” Soil and Tillage Research, vol. 158, pp. 57–66, 2016. [23] Y. Q. Gu, T. X. Fan, J. G. Mou, L. F. Jiang, D. H. Wu, and S. H. Zheng, “A review of bionic technology for drag reduction based on analysis of abilities the earthworm,” International Journal of Engineering Research in Africa, vol. 19, pp. 103– 111, 2016. [24] G. M. Liu, Coupling bionic research on the adhesion and resis- tance reduction of the earthworm surface, Jilin University, Changchun, China, 2009. [25] Y. Q. Gu, J. G. Mou, D. S. Dai et al., “Characteristics on drag reduction of bionic jet surface based on earthworm’s back ori- fice jet,” Acta Physica Sinica, vol. 64, no. 2, pp. 306–315, 2015. [26] Y. Gu, J. Mu, S. Zheng, G. Zhao, J. Ru, and C. G. Wang, “Effect of jet hole arrangement on drag reduction characteristics of jet surface,” Transactions of the Chinese Society for Agricultural Machinery, vol. 45, no. 10, pp. 340–346, 2014. [27] L. Q. Ren, Optimum design and analysis of experiments, L. Ren, Ed., Higher Education Press, Beijing, 2003. International Journal of Advances in Rotating Machinery Multimedia Journal of The Scientific Journal of Engineering World Journal Sensors Hindawi Hindawi Publishing Corporation Hindawi Hindawi Hindawi Hindawi www.hindawi.com Volume 2018 http://www www.hindawi.com .hindawi.com V Volume 2018 olume 2013 www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 Journal of Control Science and Engineering Advances in Civil Engineering Hindawi Hindawi www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 Submit your manuscripts at www.hindawi.com Journal of Journal of Electrical and Computer Robotics Engineering Hindawi Hindawi www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 VLSI Design Advances in OptoElectronics International Journal of Modelling & Aerospace International Journal of Simulation Navigation and in Engineering Engineering Observation Hindawi Hindawi Hindawi Hindawi Volume 2018 Volume 2018 Hindawi www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 www.hindawi.com www.hindawi.com www.hindawi.com Volume 2018 International Journal of Active and Passive International Journal of Antennas and Advances in Chemical Engineering Propagation Electronic Components Shock and Vibration Acoustics and Vibration Hindawi Hindawi Hindawi Hindawi Hindawi www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 www.hindawi.com Volume 2018

Journal

Applied Bionics and BiomechanicsHindawi Publishing Corporation

Published: Oct 23, 2019

References