Related Study On Mechanical Characteristic And Physicochemical Property Of Corn

Aim at study on the correlation between physical and chemical quality and mechanical properties of the grain is less, more study on the mechanical properties of corn, wheat, but other cereals research.In the study of physical and mechanical properties of grain quality, using our agricultural college exist experimental equipment, and experimental scheme drafting. and by using universal testing machine to do indentation, compression, shear test of grain. To get the correlation coefficient and establish the regression equation. Through the indentation loading-unloading experiments of the grain, the methods of the elastic plastic mechanical properties is applied to the study of micro mechanical properties of grain material. The elastic modulus, yield stress, calculated the contact stiffness are added to the material properties module of ABAQUS, to carry on the simulation of the indentation process, and according fitted curves between the simulation and experimental to verify the accuracy of T.A. Venkatesh reverse analysis algorithms in the study of cereal grain material properties, and discuss the relationship between the grain hardness and mechanical properties. This study provides a new thought and method to expand research fields of plant seed science and mechanics, provides mechanical index for links, food processing, grain breeding, has important significance for the future research on micro mechanics of grain.The main research work and conclusions are as follows:(1) The beans moisture content is in the range of 6.82%~13.79% under the condition of natural dry, the long bean 2 was the highest, 13.79%, and, Yan agricultural 2 water rate is the lowest, the average value is 6.82%. The 1000 grain weight distribution range is between179.64g~307.35 g, the weight of mung bean and red bean are smaller, respectively is179.64 g, 209.85 g, others are close, the difference is not large, the average value is 282.40 g.(2) The ash content range of legume crops are 1.12%~5.06%, the average value is 3.15%, the crude fat content range are 1.26%~6.12%, the average value is 3.48%, relatively close to the average ash content, but the overall difference varieties influence, the content of crude starch range are between 20.36%~53.37%, the average value is 41.45%, crude fiber content range are2.18%~8.28%, the average value is 5.93%, between the different legume species crude protein content range are 10.29%~34.15%, the average value is 22.45%, but on the whole is the main chemical composition of grain.(3) Indentation measured grain hardness distribution are 29.76MPa~38.94 MPa by tip, contact stiffness distribution are 431.04N/mm~116.44N/mm. Single factor in different placed ways can get flat elastic modulus, the maximum rupture force, breakage strength are slightly higher than that on the side, while on the side is greater than the value of the put, this is due to the contact area of flat on the side stand, stand at the contact area of the smallest, and the occurrence of stress concentration, so it is prone to rupture. The shear stress and shear surface area, grain ventral slit area is greater than the transverse area, so the final test results of longitudinal shear peak average value is greater than the transverse shear peak.(4) There is non-linear relationship between hardness and mechanical properties indexes. While the hardness is about 38.94 MPa, the damage intensity, elastic modulus, maximum rupture force are least. On the basis of correlation analysis, select the grain contact stiffness and hardness as the evaluation indexes to predict the corresponding index.(5) The contrast figure of the simulation analysis load curve and the experimental curve- depth are overlap, to explain and prove the validity of the simulation and T.A. Venkatesh reverse algorithm accuracy in the study of cereal grain material properties. Tin the process of abaqus simulation of indentation morphology resulting uplift occurred first for the cereal grains of four kinds that instructions the grain is plastic properties.(6) The grain hardness is proportional to the strain hardening index, the maximum equivalent stress residual stress, and yield stress are inversely proportional to the stress concentration area.hardness, contact stress, the yield stress of corn is the largest, that part of the corn surface layer are difficult to destroy during processing, transportation.