Study On Dynamic Mechanical Breaking Of Brown Rice

More than 30% of the world's population uses rice as the main food,and more than 60% of China's population uses rice as the main food.China is a major rice producing and consuming country.The use of a large number of machinery and equipment during rice harvesting,storage,transportation,and processing resulted in damage,cracking,and fragmentation of the rice.More than 70% of the broken rice came from the white milling process and the hulling of the barley.Rice with a high crushing rate is low in the international market.It is easy to breed bacteria and mold during storage and transportation,and the taste is worse when eating.At present,most of the research is on the statics of rice.In the process of rice milling,brown rice is mainly crushed by the impact force.The moisture content,variety and impact force of brown rice are the main causes of brown rice rupture.factor.Therefore,the dynamic mechanical properties and crushing mechanism of brown rice are studied in this paper.The main research contents and conclusions are as follows:1.The self-made impact test platform was used to study the impact mechanical characteristics of different varieties and different water contents of brown rice under different impact momentum.Orthogonal analysis and regression analysis were performed on the obtained test data.The analysis results show that: the impact momentum of brown rice is positively correlated with the impact force,and their relationship can be approximated as a linear function;the moisture content of brown rice is negatively correlated with the impact force;different brown rice varieties have different impact forces.According to orthogonal analysis,the primary and secondary order of factors affecting the impact force of brown rice was impact momentum> moisture content> variety.Different varieties of brown rice with different water content have obvious differences in their breaking power;as the water content increases,the breaking power of brown rice decreases.During rice milling,the impact of the white roller and brown rice played a major role in the crushing of the brown rice.The increase in the diameter and speed of the white roller increased the impact of the brown rice and the crushing rate increased.2.Using ABAQUS to conduct a finite element simulation of the brown rice's impact process,it is obtained that the images of the simulated impact force and the test impact force and time are quadratic functions of the opening downward;the regression lines of the simulated impact force and the test impact force and the impact momentum are very similar The upward trend of the two straight lines is the same,and there are stable errors between the two straight lines.These errors mainly come from the friction between the hammer and the guide sleeve,the geometrical mapping error of the brown rice,and the internal damage of the brown rice sample is not consistent.3.The scanning electron microscope was used to observe the fracture surface of the brown rice after the impact test.The analysis showed that when the brown rice was subjected to the impact force,it would be generated at the weakest part of the internal structure.Therefore,the structural strength of the brown rice depended on the binding force between the starches.The greater the impact force on brown rice,the wider the brown rice cracks and the more severe the damage.As the water content increases,the binding force between starches in brown rice decreases,and the binding force between cells also decreases.Therefore,the strength of the internal structure of brown rice decreases,and brown rice is more prone to cracks and damage.The structure of different varieties of brown rice is also different,and the degree of damage is also different when subjected to external loads.4.Scanning electron microscope images of brown rice sections were binarized using Image J image processing software,and then the fractal dimension was calculated using the Fralacac plug-in.The fractal dimension of the brown rice fracture surface was a quantitative description of the roughness of the fracture surface.Brown rice suffers from increased impact momentum,the fractal dimension of the fracture surface increases,and the impact surface increases,the fracture surface is rough,and the damage is severe.When wet brown rice is damaged by impact,the fractal dimension of the fracture surface becomes smaller,the required critical expansion force is reduced,and brown rice is more likely to be broken by impact.Different varieties of brown rice have different structural strengths,and the fractal dimension of the fracture surface when they are broken by impact is different.The above research results can provide a reference for the transportation and storage of brown rice and reduce the crushing rate of brown rice during transportation and storage.Control parameters can be provided for brown rice and rice processing personnel to reduce the crushing rate in the brown rice processing process;Design parameters can be provided for brown rice and rice processing equipment to improve the performance of brown rice and rice processing equipment and further reduce the crushing rate of brown rice.