| There was a lot of crop straw in China, but little of it was used and most of it was discardedand wasted. It was important to tap the effective using mode for crop straw in the process ofconstructing the socialism new country. It would provide better reference for production, disposal,process, transportation, pack, store if physicochemical property of crop straw, especially themechanical characteristic of invarious engineering applications was understand and mastered. Teststeps of chemical composition is complex with a long test cycle time. There were relationsbetween chemical composition and mechanical properties, so extract mechanics index to realizethe chemical composition. The thesis studied the mechanical properties of corn straw such astensile, bending, shear and friction, the stress relaxation basing on components of corn straw,moisture, etc, in order to provide the basis for the traditional straw production and processing ofassignments, the further development and utilization of crop straw resources. The main researchcontent:（1）Based on image processing technology, extracted cross section characteristic parametersof irregular cross-section of corn stover, including the area, the least moment of inertia and theminimum flexural coefficient of cross section. The correlation coefficients between this methodand other area measurement method was0.96~0.99, and this relation was very significant; Theprecision of method was around2%through standard piece test; When calculated moment ofinertia and flexural coefficient of cross section, image processing method could exclude interiorhole of the straw, that made the calculation more accutacy and closer to the truth, this was a bettersection character computing method for stalk with a hollow.（2）Consided the growth period, breed, sampling part, moisture content, speed of load, etc,completed the tensile, bending, shear mechanical properties experimental research throughuniversal testing machine. Results show that straw resistance of the maturation superior to fillingstage; Moisture content and load speed exist interaction effects on the test, under the samecondition shear failure cost less energy than other forms, and it would be least power dissipationwhen moisture was about25%in the speed of20mm/min; Speed rate had a significant effect onshear and tensile test when speed rate was between1mm/min and20mm/min; Moisture contentwas beteen5%and45%, the elastic modulus of traw exsit the max value, and this value wasrelated to varieties.（3）Test maize straw granular materials angle of repose in the different contact material.Results show that the angle of repose of lower moisture content material is mainly affected byroughness, namely board>iron plate> organic glass plate; Moisture content was between5%and 45%, friction coefficient of wood exsited the minimun value, but iron and organic glass plate exsitthe maximum value, the extremum of wall friction coefficient of three kinds of materialcorresponding was about25%; Material internal friction coefficient with the moisture content25%is the largest.（4）Stress relaxation experiment was carried out under different moisture content. Resultsshow that relaxation modulus and relaxation time are significant nonlinear influence in differentmoisture content, the moisture content was between5%and45%, the relaxation modulus of twocomponents were reduced after rising first, maximum value exsit at25%, change rule of therelaxation time was rising after reduced first, the minimum value was at about25%.（5）Tested cellulose, hemicellulose, and lignin, determination of N elements, studied therelation between mechanical properties of corn stalk and composition and establish model of therelationship based on BP neural network. |
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