耙吸挖泥船耙齿土体切削力学分析和数值仿真

发布时间：2018-04-23 01:17

本文选题：耙吸挖泥船 + 土体切削　；参考：《上海交通大学》2015年硕士论文

【摘要】：耙吸挖泥船因其具有作业时不碍航的优势,并能完成自航、吸挖、装运、吹填等疏浚全过程作业而得到广泛的应用,研究耙齿的土体切削过程对提高耙头的挖掘效率必不可少。本文从力学模型和数值仿真这两个方面入手,对此过程进行了深入研究。首先,分析对比学者基于被动土压力理论所建立的不同三维土体切削力学模型,为数值仿真所得到的结果提供参照,然后针对传统的Lagrange描述土体单元在切削模拟中所出现的网格扭曲所导致的迭代不收敛问题,引入单元删除技术的Lagrange方法和ALE方法,选用考虑土壤粘塑性的MAT147材料模型,运用LS-DYNA的动态显式算法分别对单个耙齿土体切削过程进行模拟,分析了切削过程中土的破坏形态、单元应力分布和应变特征,以及切削力与切削深度、切削速度之间的关系,指出了ALE方法在解决土体大变形与模拟土屑形态时的优势。随后进一步研究多耙齿的相互作用以及高压冲水预切削作用效果,以Godwin实验得到修正后土体侧边失效区的轮廓为基础,建立多耙齿以及存在预切削作用的力学模型,以单位破坏剖面上所需切削力的最小值为目标函数研究耙齿之间以及耙齿与冲水喷嘴的最优布置。最后运用ALE方法模拟多耙齿土体切削以及预切削作用效果,探讨了切削力随耙齿间距,槽型失效区与耙齿间距、相对位置变化的情况。
[Abstract]:Suction dredger is widely used in dredging operation because it has the advantage of not hindering navigation and can complete the whole process of dredging, such as self-navigation, suction, loading and filling. It is necessary to study the soil cutting process of rake teeth in order to improve the digging efficiency of rake head. In this paper, the mechanical model and numerical simulation are discussed in detail. First of all, different 3D soil cutting force models based on passive earth pressure theory are analyzed and compared to provide a reference for the results obtained by numerical simulation. Then, in order to solve the problem of iteration non-convergence caused by the mesh distortion that occurs in the cutting simulation of soil element by traditional Lagrange, the Lagrange method and ALE method of element deletion technique are introduced, and the MAT147 material model considering soil viscoplasticity is selected. In this paper, the dynamic explicit algorithm of LS-DYNA is used to simulate the cutting process of single rake soil. The failure pattern, stress distribution and strain characteristics of the soil, and the relationship between cutting force and cutting depth and cutting speed are analyzed. The advantages of ALE method in solving the large deformation of soil and simulating the shape of soil debris are pointed out. Then the interaction of multi-rake teeth and the effect of high-pressure flushing pre-cutting are studied. Based on the profile of the modified lateral failure zone obtained by Godwin experiment, the mechanical model of multi-rake teeth and pre-cutting is established. The optimal arrangement of teeth between rake teeth and between rake teeth and flushing nozzles is studied by taking the minimum value of cutting force required on the unit failure profile as the objective function. Finally, the ALE method is used to simulate the cutting effect of multi-rake soil and pre-cutting, and the change of cutting force with the spacing of the rake teeth, the slot failure zone and the rake tooth spacing, and the relative position of the cutting force are discussed.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U674.31

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