基于数字图像测量技术的小麦剪切过程三轴试验研究

发布时间：2018-06-03 15:58

本文选题：数字图像测量技术 + 三轴试验　；参考：《河南工业大学》2017年硕士论文

【摘要】：粮仓是一种用来储存粮食的特种结构,粮食颗粒在卸料时,由于受自身重力的作用,粮食颗粒之间相互作用,颗粒与仓壁也发生相互作用,导致粮仓的仓壁上受到的动态侧压力急剧增大,远大于静态侧压力,动态侧压力是粮仓结构设计的主要荷载之一。研究表明,粮食力学特性,尤其是剪切强度、剪切变形特性对仓内粮食相互作用影响较大,因此有必要开展粮食剪切过程试验研究,为粮仓设计提供试验依据。本文基于数字图像测量技术对全自动三轴仪进行改造,以河南小麦为研究对象,进行三轴试验研究,探索数字图像测量技术应用于粮食三轴试验的适用性,研究粮食在三轴剪切试验过程中的强度和变形特性。本文的主要研究内容如下:(1)基于数字图像测量技术对全自动三轴仪进行改装,针对该仪器,以饱和砂土为例子进行标定,研究表明,该套仪器可以用于测定散体物料的应力、体积变化等参数。(2)利用上述仪器对河南小麦进行三轴试验,改变小麦孔隙比和围压等影响因素,进行平行对比试验,得到在某种影响因素下的小麦的应力-应变关系曲线和应变-体变关系曲线。(3)基于莫尔-库伦理论,得到试样的黏聚力c和内摩擦角φ,试验结果表明,在围压为25 kPa、50 kPa、75 kPa、100 kPa,孔隙比为0.58、0.62、0.68下小麦的粘聚力在0.56 kPa~0.32 kPa之间,内摩擦角在25.13°~23.57°之间。(4)计算出孔隙比为0.58时,低围压下小麦的剪胀角介于16.29°~13.85°之间;围压为25 kPa,孔隙比为0.58、0.62、0.68时小麦的剪胀角介于16.29°~15.13°之间。(5)对该套仪器采集的数据进行后处理后,采用surfer软件绘制出小麦试样变化的应变图以及对应的矢量图,结果表明,小麦试样被压缩,试样外观表现出良好的对称性,属于鼓状破坏。
[Abstract]:The granary is a special structure for storing grain. In the discharge of grain, grain particles interact with each other because of its own gravity, and the grain and the wall of the silo also interact, which causes the dynamic lateral pressure on the warehouse wall of the granary, which is much larger than the static side pressure, and the dynamic side pressure is the design of the granary structure. One of the main loads. The study shows that the mechanical properties of grain, especially shear strength, and shear deformation characteristics have great influence on the grain interaction in the warehouse. Therefore, it is necessary to carry out experimental research on grain shearing process and provide experimental basis for the design of granary. Based on the digital image measurement technology, the automatic three axis instrument is reformed to Henan. As the research object, the three axis test is carried out to explore the applicability of digital image measurement technology to the three axis test of grain, and to study the strength and deformation characteristics of grain during the three axis shear test. The main contents of this paper are as follows: (1) based on the digital image measurement technology, the full automatic three axis instrument is modified, and the instrument is aimed at the instrument, Taking the saturated sand as an example, the study shows that the instrument can be used to determine the stress and volume change of the bulk material. (2) the three axis test of Henan wheat was carried out with the above instruments to change the factors such as the pore ratio and the confining pressure of wheat, and the parallel ratio test was carried out to obtain the stress of the wheat under some influence factors. Strain relation curve and strain body variable relation curve. (3) based on the Mohr Kulun theory, the cohesive C and internal friction angle of the sample are obtained. The experimental results show that the confining pressure is 25 kPa, 50 kPa, 75 kPa, 100 kPa, and the cohesion of the wheat is between 0.56 kPa ~0.32 kPa under the pore ratio and the internal friction angle is 25.13 [4]. (4). When the void ratio is 0.58, the shear bulging angle of wheat under low confining pressure is between 16.29 ~13.85 degrees, the confining pressure is 25 kPa, and the shear bulging angle of the wheat is between 16.29 degrees ~15.13 when the pore ratio is 0.58,0.62,0.68. (5) after the data collected from this instrument are processed, the strain map of the change of wheat samples and the corresponding vector are drawn by the surfer software. The results showed that the wheat samples were compressed and the appearance of the samples showed good symmetry, which belonged to drum damage.
【学位授予单位】：河南工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP391.41;S512.1

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