| It is significant for the Country and people, even for sustainable agricultural ecosystem to utilize and develop crop straw resources. Cutting process of straw is the first important tache for feeding and commercial production of straw during the utilization of straw feed. Cutting process of straw affects the energy consumption of the machine, causes wastage of cutters on the machine, and have an impact on the straw process quality. The physical properties of straw are important basis for designing and improving the machine and processing technics, and it varies greatly from the engineering materials. Therefore, the test-bed of physical properties which could simulate the cutting process of straw was designed to provide the academic basis for optimizing the parameters of the machine. The abrasion resistance and strength toughness of cutters with cutters of different materials, different structures and different processing were studied. Results have been showed as below.Firstly, mechanics properties of corn straws have been discussed by experiment on three-point bending corn straws on the materials testing instrument in the paper. The microstructure of corn straws has been observed by SEM. Results show that there were two phases during the rupture of corn straw. Maximum of broken force reached 215.44N, and that of displacement reached 15mm. The mechanics of corn straws is relative to its microstructure. Broken force was affected by cross area of straws, storage time and position of nodes.Secondly, based on analysis of the structural theory of the machine processing straw, a new test-bed cutting straws has been developed. It contains four systems, includes accelerating system, acquisition system of strain parameter, high-speed photographs system and main controlling system. And it is convenient to arrange testing apparatus on the test-bed. And it is easy to operate.Thirdly, The cutting process of straws has been recorded by high-speed photograpy camera. Motion law for the process of straw cutting was analyzed with MAS (motion analysis system).Fourthly, based on the experimental study and theoretic analysis, key factors affecting the process of cutting of corn straws have been researched on the new test-bed for cutting straw. Cutting speed and clearance between moving and fixed cutter are both the key parameters affecting the cutting resistance and rate of cutting straw for wheat and paddy straw which are acerose and flexile, influence of tartness of the cutters on the cutting resistance and rate of straws cutting was very important as well.Fifthly, the paper investigates the relationships between the cut resistance, cutting rate and key factors, such as cutting speed, clearance between moving and fixed cutters, count of cutting straws, and straws water content by means of regression orthogonal analysis method. Regression models about the relationships were established. A target function from cut resistance model and rate of straws cutting model has been constructed by weighted linear summation method. A bi-index optimization of straws cutting has been carried out by Matlab , and a group of optimized parameters were obtained.Finally, cutters abrasion experiment has been conducted on the 9RZ-60 model straw rubbing and cutting machine in the paper. Macro-analyses and micro-analyses, and analyses of chemical compositions of the cutter made of 65Mn and metallographic examinations are observed by SEM. It indicated that bladematerials and cutters position in the workroom on the machine and properties of straws were the main factors to the blade wear respectively. Because of over-heated, hardness of part blade on the cutter is inadequate. The cutter made of 65Mn was not heated specially after forging. A new heat treatment scheme was conducted, and collocation of cutters in the workroom was changed, and three kinds of feeding form were designed. Results show that the life of cutters was extended, and blade materials wastage was reduced, and productivity of the rubbing and cutting machine was increased, process quality was improve...
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