Study Of The Reducing Resistance And The Genetic Optimization Of The Pit Bionic Non-smooth Surface

As a work supported by the National Key Grant Program of Basic (Grant No. 2002CCA01200) and the National Natural Science Foundation of China (50175045), the core of the paper is the discussion about the soil frictional resistance and the optimization of capacity of reducing frictional resistance of the pit bionic non-smooth surface.Adhesive and frictional interface system exists between the soil and the surfaces of soil-engaging components on a variety of terrain machines including tillage and sowing machines. This phenomenon of soil adhesion and friction not only increases the working resistance and energy consumption of these machines, but also decreases the quality of work. Adhesive and frictional interface system is an important object in the study of Soil Mechanics. The bionic surface design of soil engaging components is one of the important techniques for reducing soil adhesion and frictional resistance. The optimal bionic surface design is an object that people want to obtain. In this paper the mathematical modeling is built according to the body surface of dung beetle and it provide the modeling base for the optimization of the non-smooth surface. The reasons are got for the first time by analysizing the experiment phenomenon of the soil frictional interface. In order to analysize the soil resistance of the pit non-smooth surface, the pressure-sinkage experiment of the holly circular plate was done for the first time and the sinkage equation are obtained by regression. Then combined the Morh-Kuln equation and the soil resistance regress equation, the mechanical modeling of non-smooth surface are established. The average reducing resistance rate is made the standard to evaluate the non-smooth surface. According to work condition, the mathematical programming is built and solved by the genetic algorithm. The optimal parameters of the non-smooth surface are got and anlysized. Finally the experiments of the soil frictional resistance were done to valid the optimal result. It will provide a new study method for the bionic design of the soil engineering component.The shape, the size and the distribution of the non-smooth surface unit are important impact factors that affect the resistance between the soil and the solid surface. So it is very important to study the mathematical modeling of the non-smooth surface. In this paper, the non-smooth structures of the dung beetle body surface which have the best ability of reducing adhesive and frictional resistance are made the bionic modeling object. The unit shape and the distribution of the pit non-smooth are built according the non-smooth body structures of the dung beetle. It is very significant for the diversity and optimization of the non-smooth surfaces and provide.Bionic non-smooth surface technique to reduce the adhesive and frictional resistance is a very hot problem for many researchers. Some researchers explored the reasons and the mechanism of the reducing adhesive and frictional resistance of the non-smooth surface. The interface phenomenon analysis of the soil frictional procedure was black because the phenomenon can not be observed by traditional experiment method. In order to explore the phenomenon, the members in our research team adopted the glass plate to observe the changes of the soil and the air etc. in the soil frictional procedure. The reasons of the reducing resistance of the non-smooth surface were analyzed by the experimental phenomenon photos. The results showed that the holes and air films were easily formed for the pit non-smooth surface in comparison to the smooth surface, and the existence of the pits of the non-smooth surface made the contact area decreased and the water films discontinuous obviously. Consequently the pit non-smooth surface could reduce resistance between the soil and the solid.The soil resistance of the non-smooth surface was always got by the soil resistance experiments for a few kinds of the non-smooth surface. In this paper a new method that was to study the procedure of soil sinkage of holly circular plate was applied for the soil resistance study of the pit non-smooth surface for the first time. Combined the Morh-Kuln equation and the pressure-sinkage equation and the soil resistance of certain non-smooth surface, the mathematical relation between the soil frictional resistance and the press, the velocity, the water contain, the pit area rate and the pit radius were established.The pressure of natural selection is an irresistible force shaping all of nature. The non-smooth surface of the soil animal is the optimization and evolution by hundreds of millions years. But the non-smooth body surface structures of the soil animal is not obviously fit for the bionic design the soil component because of the got-up technique and the cost. Many researchers are always eager to find the non-smooth surface which has the best ability of reducing resistance. Based on that aim, the average rate of reducing resistance is made standard for the ability of the reducing adhesive and frictional resistance. According to the different work conditions, the mathematical programming for the non-smooth surface parameters is established. The object function of the programming is very complicated linear and scatter and it is very difficult to solve by the traditional algorithms. Genetic algorithm is chosen because it excels on the traditional algorithm sometimes. The optimal parameters of non-smooth surface were got under the different work conditions and the results were analysized.In order to prove the optimal result is efficient, the soil frictional resistance experiment was performed with the smooth plate, the original non-smooth plate and the optimal non-smooth plate. The experimental results showed that the average rate of reducing resistance of the optimal plate was 9.36% and that of the original non-smooth plate was 6.51%. The average rate of reducing resistance of the optimal plate was increased by 2.85%. The experimental results were accord with the theoretical analysis.The study achievements in this research show that the pressure-sinkage method is efficient to solve the soil frictional resistance of the non-smooth surface problem, and genetic algorithm is feasible for the optimization problem of reducing resistance of the non-smooth surface. It provides a new study thought and method of the bionics and optimization for other soil engaging components.