挖掘机獾爪趾仿生斗齿提高其入土性能仿真与试验

为解决挖掘机斗齿入土阻力大，易断裂的问题，该文利用Handyscan700扫描仪获取獾右前爪中趾表面的三维点云，提取獾爪趾的侧面轮廓曲线，并进行拟合得到曲线方程，将获取的曲线方程运用到斗齿的设计中，利用三维软件建立斗齿模型。运用有限元分析软件对仿生斗齿和80型斗齿的力学性能和切土过程进行数值模拟，对比分析了力学性能的差异以及能量损耗与切土深度的关系。采用快速成型加工技术加工出了仿生斗齿与80型斗齿试样。利用电子万能试验机对2种试样进行了楔土试验，测定了楔入阻力与楔入深度的关系。结果表明：在施加相同载荷的情况下，仿生斗齿所产生的最大等效应力小于80型斗齿的，破坏的可能性小，比较安全；当斗齿的入土深度相同时，仿生斗齿的消耗的能量总小于80型斗齿；在同样条件下，仿生斗齿的楔入阻力较80型斗齿低11.9%～12.6%。该文以獾爪趾为仿生原型设计的挖掘机斗齿不仅解决了工程中遇到的问题，还为减阻部件的开发提供了新思路，具有重要的参考价值。

Simulation and experiment of badger claw toe bionic excavator bucket tooth for improving performance of digging and cutting

In order to solve the problems of high resistance and fracture in excavator bucket tooth, a bionic excavator bucket tooth was designed. Bucket tooth is assembled in the bucket tip, which is an important component of excavator, and its performance directly impacts the performance of bucket and even excavator. The bucket tooth is prone to abrasive wear during the operation, which could result in the reduction of cutting capacity. Improvement of bucket tooth configuration is one of the methods to improve the performance of bucket tooth. In this paper the badger was selected as the research object. Badger is a mammal, which is distributed in most parts of Europe and Asia. Badger is good at digging and it is a kind of burrowing animal. Badger owns slender and bending front claws, which are a powerful tool for digging. Therefore, by inspiration of that, the claws could provide a good bionic prototype for the design of bucket tooth. All of the following experiments were finished in the Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University. Handheld three-dimensional (3D) scanner (Handyscan700, Canada, Creaform company) was used to obtain the 3D point cloud of badger claw toe. This experiment was carried out in April 15, 2015. Due to the darker surface of badger claw toe, the toe had been sprayed with a layer of white power to enhance the results before scanning. The scanning results were imported into the reverse engineering software (Geomagic), and the contour curve of the longitudinal section of the badger claw toe was obtained through a series of processing. Then, the curve equation of the inner surface and the outer surface of the badger claw was obtained by curve fitting. Taking 80 type bucket tooth as a reference, the curve equations were applied to the design of bionic bucket tooth, and the bucket tooth model was established by utilizing the curves. Finite element analysis software (Abaqus) was implemented to analyze the mechanical properties of 80 type bucket tooth and bionic bucket tooth. The material, density, elastic modulus, Poisson ratio, yield strength of bucket tooth model were Mn13, 7900 kg/m3, 210 GPa, 0.3 and 390 MPa respectively. The working face of the 80 type bucket tooth model was applied to a positive pressure, and the pressure value was increased from 1 to 12 MPa. For each simulation, the positive pressure load was increased by 1 MPa. The equivalent stress of bucket tooth models was analyzed. The result showed that the maximum equivalent stress of the bionic bucket tooth was less than the 80 type bucket tooth in the same case of applying load. The models of bucket tooth wedging soil were established by Abaqus. In order to save computation time, the size of the bucket tooth models was the quarter of reality, which could not affect the results. The depth into earth was 20 mm. The result showed that when the depth was the same, the energy loss of the bionic bucket tooth was less than 80 type bucket tooth. The bucket tooth models were imported into 3D printer (ProJet5500X, 3D Systems Company, America) for processing. The bucket tooth material was ABS (acrylonitrile-butadiene-styrene copolymer) rubber. In addition, in order to save the material and processing cost, the sample size was 0.6 times of the prototype. This experiment was carried out on December 28, 2015. The bucket teeth samples were installed in the Electromechanical Universal Testing Machine, and then the buried resistance was tested. This experiment was carried out on October 25, 2015. The cutting direction selected was vertically downward, and the cutting speed was 100 cm per minute. Five times repeated trials were implemented, and the average values were attained. The maximum cutting depth was set to 40 mm. The results showed that the wedging resistance of bionic bucket tooth was 11.9%-12.6%lower than the 80 type bucket tooth under the same condition. In this paper, the bionic bucket tooth can provide a reference for designing excavator bucket tooth with better mechanical properties. Further more, it can provide a new idea for the contact soil parts to reduce resistance and has important reference value for design.