【作者】 朱凤武；

【导师】 佟金；

【作者基本信息】 吉林大学 ， 农业机械化工程， 2005， 博士

【摘要】 深松作为保护性耕作的重要措施之一,耕作阻力大,能耗高是其主要特征。本论文从工程仿生学角度出发,通过对深松部件进行仿生设计和参数化分析,以降低深松部件的耕作阻力作为研究的重点。首先对金龟子科动物体形特征参数进行分析,比较各科属体形参数的变化规律。并分析了以蜣螂为代表的金龟子科动物前足胫节各齿形态特征:基齿、中齿及端齿角度;前足胫节各齿顶端轮廓线及其外缘轮廓线的形状,属于二次抛物线形状,拟合精度较高,这种抛物线形状有利于动物挖掘土壤和减小阻力,为深松部件的仿生设计提供了依据。其次,对金龟子前足楔形爪趾与土壤相互作用进行受力分析,以二面楔和三面楔的工作原理为理论基础,将其应用到深松铲的受力分析,建立了深松铲牵引阻力的数学模型。并利用动态三轴仪对耕作土壤进行了三轴测试试验,得出了试验土壤的机械特性参数,以Drucker-prager 弹塑性本构关系为土壤材料模型,进行了深松部件与土壤相互作用的有限元分析。最后,基于金龟子前足胫节齿顶轮廓线与外缘轮廓线的抛物线形状,采用VC 程序设计语言并结合ANSYS 程序,建立了深松铲形状参数化程序,得出各种参数下的深松铲牵引阻力,以此对深松铲形状参数进行优化。在上述研究的基础上对仿生深松部件进行田间测试,分析了影响深松牵引阻力的主次因素,并对实测值与参数化程序的计算值进行比较,结果表明,用参数化设计的方法来优化深松部件的仿生设计是可行的,而且采用UHMWPE 基复合材料对深松铲面进行处理能有效地减小深松铲的牵引阻力。上述研究工作及其所取得的成果突破了传统深松部件形状设计研究思路,提出了参数化程序设计和优化的方法,为深松部件的设计提供了一定基础。更多还原

【Abstract】 The morphology features of scarabaeoidea and tibiae teeth of its fore leg , their bionic applications in subsoiling components and the optimization of shape parameters of subsoiling components is the main emphasis of research in this dissertation, which is projects supported by Nationl science Fund for Distinguished Young Scholars(Grant No.50025516) and by National science Foundation of China(Grant No.50275037). The figures parameters of dung beetle was analyzed, which is the results of the lasting evolution and adaptation for environments. The teeth angles of fore-leg tibiae of the dung beetle was measured, which is radix tooth 69.3°, the first middle tooth 44.3°, the second tooth 32.1°and the apical tooth 27.5°and has a descending trend. The wedge shape of teeth top of scarabaeoidea is suited for anti-adhesion against soil thereby reducing adhesion and resistance.The contour lines of teeth and its top are measured, which can be fitted by parabolic. The parabolic shapes of teeth contour have the characteristics of digging process and reducing the cutting resistance, which offers the base on the bionics design of subsoiling components. The force of the wedge teeth of fore-leg of scarabaeoidea and soil interaction was analysed by the work theory of two-surfaces and three-surfaces wedges and apply to the forces analysis of subsoiling components cutting the soil. The results have showed the draft force is composed of three parts: the first R1 is brought by shovel edges and handle edges cutting soil, the second R2 is brought by the soil smashed and the third is the friction force between the subsoiler and soil. The draft force of subsoiler is the sum of three parts force along to the advance directions. The mathematic model of subsoiler draft force was concluded by the analysis and applied the theory of subsoiler force and the parameterized design of the bend surface of subsoiler. The subsoiler components —soil interaction is researched by the Finite Element Methods based on the Drucker –Prager elastic—plastic soil construction relationship model. The shape parameters of subsoiler component was established by the parabolic shape of the teeth contour lines of scarabaeoidea fore-leg tibiae. The inter-contour lines of the subsoiler components is the parabolic shape and selects the three sections (A-A,B-B and C-C) to determine the subsoiler shapes. The subsoiler surface was optimised by the parameters L1,L2,L5 and L6. The parabolic shapes was adopted in the subsoiler tip and the digging angleαwas determined by the angle A1, A2. The parameterized program of subsoiler components was established by the Vc programmer combining the ANSYS finite element program and realized the parameterized analysis of subsoiler. The draft force of subsoiler component can be calculated by inputting the soil parameters (elastic module, poission’s ratio, soil cohesion and angle of internal friction in soil et. al ), subsoiler materials parameters and the friction coefficients between the subsoiler and soil. The stress status of the soil and subsoiler can also be showed by the ANSYS program. The design method of bionic subsoiler is summarized based on the above research wherein subsoiler of different digging angles shapes are designed. The draft force of subsoilers was tested by orthogonally experimental design in field. The results shows that the best digging angles is 27.50 consistent with the apical tooth angle of fore-leg tibiae of scarabaeiodea. The comparative results between the actual test draft force and the calculated force value of parameterized program shows the test value is comparable to the calculated value and has only 0.9% error. It shows the parameterized program can be calculated the draft force of subsoiler and also optimize the shapes parameters of subsoiler components.更多还原