DEFORMATION AND STRESS ONLINE MEASUREMENT SYSTEM IN SOIL BIN TEST BY THE APPLICATION OF PIV

本文的主要研究成果如下：1.利用PIV技术研制了土槽试验中土壤位移的在线测量系统（粒子图像测速仪）2.编制了由土的位移分布计算应变张量的计算机程序; 3.编制了由土的位移分布计算应力张量的计算机程序; 4.编制了由土的位移分布计算应力张量的计算机程序。4.在土槽试验装置上，测量了不同接触载荷和滑移情况下轮下土壤的位移、应变和应力（Hashiguchi和Ueno，1977年; Hashiguchi，1989年）和次加载摩擦模型（Hashiguchi，Ozaki和Okayasu，2004），而次加载面模型不仅能够处理材料的单调加载行为，而且能够处理材料的循环加载行为。7.通过试验结果与计算结果的对比，验证了分析的正确性; 8.通过分析，解释了车轮牵引力随滑移率增大而增大的现象，这不能用引入库仑摩擦定律的有限元程序来解释，因为它预测了即使在无限小的滑动下的最大牵引杆拉力。9.通过有限元分析来解释土壤压实过程。10.此外，对绿色房屋的拔桩和筒仓内颗粒的流动进行了分析，并与试验数据进行了对比，验证了分析的有效性，这些结果将有助于农业机械和器具的机械设计的发展。

The measurement of deformation and stress in soils beneath the traveling devices is of importance for the mechanical design of farm machinery The following results have been obtained.1.The online measurement system for displacement of soils in soil bin test is developed by using the PIV (Particle Image Velocimetry).2.The computer program for calculation of strain tensor from the displacement distribution of soils is developed.3.The computer program for calculation of stress tensor from the strain is developed.4.The displacement, strain and stress in soils beneath the wheel in soil bin test apparatus are measured for various contact loads and slips.5.The finite element program introducing the subloading surface model (Hashiguchi and Ueno, 1977 ; Hashiguchi, 1989) and the subloading friction model (Hashiguchi, Ozaki and Okayasu, 2004) is developed, while the subloading surface model is capable of not only the monotonic but also cyclic loading behavior of materials.6.The displacement, strain and stress in soils beneath the wheel are analyzed using the finite element program.7.The validity of the analysis is verified by the comparison of the experimental results and the calculated results.8.The phenomenon that the drawbar-pull of wheel increases with the increase of slip is explained by the analysis, it could not be explained by the finite element program introducing Coulomb friction law since it predicts the maximum drawbar-pull even in an infinitesimal slip.9.The soil compaction process is explained by the finite element analysis.10.Besides, the extraction of piles of green house and the flow of particles in silos are analyzed and their validity is verified by comparison with test data.These results would contribute to the development of mechanical design for agricultural machinery and apparatus.