Chirende Benard, Li Jian Qiao, Vheremu Wonder
School of Agricultural Sciences, University of Mpumalanga, Private Bag X11283, Mbombela 1200, South Africa.
Key Laboratory for Terrain-Machine Bionics Engineering (Ministry of Education), Jilin University, Changchun 130025, China.
Biomimetics (Basel). 2019 Sep 3;4(3):61. doi: 10.3390/biomimetics4030061.
Ansys software was used to carry out three-dimensional finite element analysis (FEA) for biomimetic design of harrowing discs based on the body surface morphology of soil burrowing animals like dung beetle () which have non-smooth units such as convex domes and concave dips. The main objective was to find out the effects of different biomimetic surface designs on reducing soil resistance hence the horizontal force acting on the harrowing disc during soil deformation was determined. In this FEA, soil deformation was based on the Drucker-Prager elastic-perfectly plastic model which was applied only at the lowest disc harrowing speed of 4.4 km/h which is within the limits of model. The material non-linearity of soil was addressed using an incremental technique and inside each step, the Newton-Raphson iteration method was utilized. The model results were analyzed and then summation of horizontal forces acting on the soil-disc interface was also done. An experiment was then conducted in an indoor soil bin to validate the FEA results. The FEA results are generally in agreement with those of the indoor experiment with a difference of less than or equal to the acceptable 10% with an average difference of 4%. Overall, convex bionic units gave the highest resistance reduction of 19.5% from 1526.87 N to 1228.38 N compared to concave bionic units.
基于蜣螂等穴居动物的体表形态，其体表具有诸如凸穹和凹坑等非光滑单元，利用Ansys软件对耙片进行仿生设计的三维有限元分析（FEA）。主要目的是找出不同仿生表面设计对降低土壤阻力的影响，从而确定土壤变形过程中作用在耙片上的水平力。在该有限元分析中，土壤变形基于Drucker-Prager弹塑性模型，该模型仅应用于最低耙地速度4.4 km/h，此速度在模型限制范围内。采用增量技术处理土壤的材料非线性，在每个步骤中，使用牛顿-拉夫逊迭代法。对模型结果进行分析，然后对作用在土壤-圆盘界面上的水平力进行求和。随后在室内土槽中进行实验以验证有限元分析结果。有限元分析结果与室内实验结果总体一致，差异小于或等于可接受的10%，平均差异为4%。总体而言，与凹形仿生单元相比，凸形仿生单元的阻力降低幅度最大，从1526.87 N降至1228.38 N，降幅为19.5%。
