Experimental Research On The Mechanical Physical Parameters Of Wheat Stalks In Harvesting Period

Agriculture plays a very important role in the national economy in China, which is a large agricultural country in the world. Wheat as one of the three major food crops, its root, stem and leaf is a natural organic polymer materials, on the one hand, due to so many technical problems relevant to biological stalks are not resolved, bring about lack of critical foundation parameter for exploiting biomass more high efficiency and safety, which constrained development of comprehensive utilization to technological, safety and industrialization for biomass in our nation, which greatly limits its application. Wheat stem is the trunk of the plant that is the basis for normal growth, but lodging is one of the most major limiting factors in process of growing, more importantly, it decides the quality of the group better or not. Therefore, the wheat stalks were tested by tensile, shear and bending tests on the Texture Analyzer with different experimental factors, which consist of different internodes, loading rate and moisture content, obtaining mechanical properties parameters of wheat stalks under different experimental conditions, its results were analyzed by the mathematical statistical software of SPSS12.0for single factor analysis of variance, acquiring the factor that affect the mechanical properties parameters of wheat stalks under different test conditions. It can provide an important reference for lodging resistance and comprehensive utilization.The main contents and conclusions by testing are as follows:(1) Variation of the load in the curve of load-displacement were analyzed by tensile, shear and bending tests. When the wheat stalks were stretched, the maximum load and the ultimate strength on the second to fourth internodes of Yi-bin NO.1wheat stems growth along the direction of growing, but the Xi-nong NO.889is exactly the opposite. This result is different caused by the thickness between the stalk section. When the wheat stalks were sheared, the shear strength is trend to decreases and then increases for wheat stems of Yi-bin NO.1, Ai-kang NO.58, Zhou-mai NO.22and Yu-mai NO.7. When the wheat stalks were bending, the Young’s modulus of upper is bigger than middle internodes of Zheng-mai NO.9023, Zhou-mai NO.22and Ping-an NO.6.(2) There are diversity in different part of wheat stalks when the substance were transported and stored in the process of growing, so the different internodes of wheat stalks were tested by tensile, shear and bending experiment for get the mechanical properties parameters, its results were analyzed by the mathematical statistical software of SPSS12.0for single factor analysis of variance, the record shows that the different internodes has greatly significance impact on the ultimate strength, Young’s modulus and bending rigidity, but has no significance impact on the shear strength, which indicated that the internodes is an important factor to affect tensile and bending properties, but not to shear strength.(3) Due to reading related articles of domestic and foreign scholars about wheat stalks that were tested for tensile, shear and bending, each experiment use different loading rate. So the different loading rate was designed for it has a significant impact on the ultimate strength, shear strength and Young’s modulus of wheat stems in the same internodes. The result by analysis of statistical software shows that the different loading rate has no significance impact on the ultimate strength, shear strength and Young’s modulus of wheat stems in the same internodes, but has an greatly significance impact on the bending rigidity.(4) Moisture content has a greater impact on the mechanical properties of crop stalks, the wheat stalks were tested by tensile, shear and bending experiment under the different moisture content, the research by analysis of statistical software shows that the moisture content has an important significance impact on the ultimate strength, shear strength, Young’s modulus and bending rigidity of wheat stems in the same internodes. Therefore, the moisture content is an important factor for Characterization of tensile, shear and bending properties of wheat stalks.(5) The length gauge has an important significance impact on the Young’s modulus that shows it was a other greatly factor to affect bending mechanical properties.