Simulation Analysis Of Collision Process Of Soybean Based On The DEM

When the working parts of agricultural machinery works, it always follow the flow of agricultural material. For example, when seed-metering device meters, there is flow of seeds, fertilizer, soil of the time; while turning over and plowing the farmland, there is a movement of soil all the time; Agricultural product reaping, transporting, grading, processing and packing, are followed by relevant movement of agricultural particle material all the time too.The movement of agricultural particle material relates to not only one's own mechanics nature, but also has something to do with relevant agricultural machinery, especially the structure form and performance parameter of its working parts. A good agricultural machinery design should make agricultural particle material move according to the way that it is anticipated, such as the movement of seeds while seeding; it can reduce the unnecessary damage in the moving course, such as the seed is damaged while seeding; it can save mechanical motive force to consume, such as draw motive force to consume while ditching, plowing and turning over the soil; it must consider the interaction of working part of agricultural machinery particle material , including the dynamics characteristic at this moment.The research and design of seed-metering mechanism mainly have two kinds of methods. One is the design method and theory based on the continuum mechanics method, but it considers granular particles as a continuous whole, as a result it can not analyze the movement process of every particle and interactions between particles, so it can not solve problems existing during designing seed-metering device well. Another method is according to the experience and trial, whereas usually it is not only time-consuming but also strenuous without ideal results.DEM proposed by Cundall in seventies of the 20th century is popular method to research particles dynamics problems. The interactions between granular materials and seed-metering and the flow process of seeds are studied by the DEM, which can be used to estimate the working performance of seed-metering, such as the rate of single seed, the rate of empty cave and the rate of destroyed seeds etc., and also to simulate and evaluate the dynamic working process of seed-metering machine. Thus the seed-metering mechanism of new theory can be found, however, it can not be realized by the existing design methods and technologies.A basic theory of DEM of the 3-dimension round was built to simulate the soybean seed, based on studying the present conditions and existing problems concerning the DEM that the domestic and external literatures have been reported, two conceptions of fact boundary and false boundary were proposed to solve the graphic primitive imperfect and different graphic primitive's intersection, when building a model based on graphic primitive's 3-dimensions DEM boundary. The research object that regards the grain as the contact, judge with a few diagrams a boundary to grain, the coincidence matches the calculation, grain contact dint of the...