道路坚实冰雪清除机理及关键部件研究

发布时间：2018-03-05 01:20

本文选题：除雪机具　切入点：除雪机理　出处：《吉林大学》2015年博士论文　论文类型：学位论文

【摘要】：我国北方冬季大部分地区一直被清雪问题所困扰，这些地区降雪周期长、雪量大、范围广。未能及时清除的道路积雪经过车辆和行人的反复碾压、气温变化的反复融冻，形成了表明结冰、内部含杂的板状、冰膜状坚实冰雪。坚实冰雪覆盖的路面给车辆和行人带来不便的同时也增加了发生交通事故的几率。根据有关方面对全球各大中城市调查结果，城市路面积雪结冰造成的交通事故占冬季交通事故总量的20%以上，己成为世界公认的“白色”城市危害。因此，研发新型、快速、环保、高效的道路坚实冰雪清除设备至关重要。分析了坚实冰雪的类型转换过程及形成形式，阐述了冰雪密度、抗压强度、抗剪切强度、摩擦因数等物理特性参数，利用体视显微镜观测了自然冻结冰雪和碾压冰雪的表面结构。在对冰雪颗粒微观描述的基础上，基于Bazant思想构建了冰雪微观结构模型，将冰雪微观结构变形机理与宏观连续行为联系在一起，建立了坚实冰雪本构模型。利用冰雪单向压缩破坏试验和三轴加载破坏试验，分析了处于道路边缘无侧压的冰雪及处于道路中间有围压冰雪的受力状态及破坏特性。试验结果证明了所建立坚实冰雪本构模型的合理性及适用性。该本构模型较好的描述了坚实冰雪应力-应变关系的宏观性质，适用于应变率大于0.5×10-5/s的滑雪、碾压冰雪等密度较大的坚实冰雪，为坚实冰雪清除理论提供了理论参考。利用高速摄像仪对坚实冰雪切削破坏过程观察分析发现，坚实冰雪的破坏形式主要为脆性断裂，破坏的原因为刀刃切入和冰雪撕裂综合作用的结果。基于冰雪本构模型及切屑剥落过程，建立了刀具切入冰雪出现破坏裂纹临界状态的物理模型，对除雪刀具进行了力学特性分析，给出了坚实冰雪切削破坏的数学模型，建立了新的冰雪破坏准则。该准则考虑了冰雪本构特性，认为冰雪在最薄弱部位发生局部破坏，生长为较大裂纹，进而产生断裂破碎。新破坏准则的建立为坚实冰雪的高质高效清除提供了理论依据。搭建了测量冰雪切削阻力的试验台，进行了坚实冰雪切削破坏试验，试验证明了所建立破坏准则的合理性。以切削阻力最小为目标，安装角、刀具前角、切削深度为影响因素，实施了三因素五水平旋转正交除雪参数分析试验，试验证明了切削阻力数学模型的正确性，同时进一步证明了所建立破坏准则的可用性。针对不同状态、不同密度的坚实冰雪，研发了凹盘式及立铣式除雪关键部件，两种部件均创新的采用了分体组合独立随动仿形机构，仿形越障效果优良，除净率高。凹盘式除雪关键部件为除雪凹盘被动切削冰雪，针对低密度板状碾压冰雪，能耗低、效率高，可一次性完成压溃、切碎、掀动、刮除和推送五项作业。立铣式除雪关键部件为除雪刀主动切削冰雪，针对冰膜状、冻结状的高密度冰雪具有极强的破碎能力，同时兼有铣削、破碎、仿形、越障等功能。设计了四组单体组合凹盘式除雪试验机，以行进速度、入雪深度、凹盘刃口角度、凹盘与行进方向的夹角为影响因素，除雪阻力、除净率、清除雪块体积为目标函数，进行了四因素五水平二次回归旋转正交试验，确定了除雪作业最优参数组合。理论与试验综合分析确定了凹盘式除雪关键部件主要参数：凹盘与行进方向夹角为13°，凹盘盘片直径为400mm，，凹盘盘片厚度为3.5mm，凹盘刃口角度为20°，凹盘曲率半径为650mm。对立铣式破冰除雪关键部件进行了运动分析及动力学仿真，仿真运动轨迹曲线与除雪机实际运动轨迹曲线一致，验证了理论及仿真分析的正确性。设计了立铣式破冰除雪试验机，以刀具安装角、行进速度、主轴转速为影响因素，除净率、清除雪块体积为目标函数，进行了三因素五水平二次回归旋转正交试验，确定了立铣式试验机除雪作业最优参数组合。在三种路况条件下实施了凹盘式及立铣式两种样机除雪工作性能和作业质量的综合试验。试验结果表明，凹盘式及立铣式除雪样机均运转良好，除雪作业效率高，除净率均高于90%，参数设定及各项指标均能达到除雪作业要求。凹盘式除雪关键部件适用于密度小于550kg/m3，厚度范围为10~80mm的板状碾压冰雪。立铣式除雪关键部件适用于密度为300~750kg/m3，厚度小于50mm的板状、冰膜状冰雪，尤其适用于密度大于550kg/m3的冰膜状冻结冰雪。两种样机的除雪试验为坚实冰雪清除技术研究及除雪机具开发提供了理论依据。
[Abstract]:Most areas of our country has been the northern winter snow snow problems, these areas for a long period, large amount of snow, a wide range. Failed to clear roads of snow after the vehicles and pedestrians repeated rolling temperature, repeated freeze-thaw, formed that ice plate internal impurity, ice solid membrane solid ice. Snow covered road to vehicles and pedestrians inconvenience also increases the probability of traffic accidents. According to the relevant aspects of the world each big city city survey, snow and ice on the road traffic accidents caused by traffic accidents in winter accounted for more than 20% of the total, has become the world recognized the "white city" harm. Therefore, the research and development of new, fast, environmental protection, efficient road solid snow removing equipment is essential.
Analysis of the types of solid ice conversion process and form, elaborated the ice density, compressive strength, shear strength, friction coefficient and other physical parameters, the surface structure of the frozen snow and natural observation with microscope. The rolling snow ice particles based on the micro description, Bazant constructs the ice microstructure based on the model, the ice microstructure and deformation mechanism and macroscopic behavior together, to establish a solid ice constitutive model. Using ice uniaxial compression test and the three axle load damage failure test, analyzed in the edge of the road without lateral pressure snow and the middle of the road in a stress state and failure characteristics of the confining pressure of ice and snow. The test results prove the rationality and applicability of the established solid ice constitutive model. The constitutive model to describe the stress-strain relationship of solid ice macro It is suitable for skiing with greater density than 0.5 x 10-5/s, which provides a theoretical reference for the theory of solid ice and snow removal.
By using high speed camera on the solid ice cutting failure process analysis it is found that the damage in the form of solid ice, mainly for brittle fracture, the failure reason for the comprehensive effect of blade cut and snow tearing results. Ice constitutive model and chip peeling process based on a knife cut out ice physical model crack failure of critical state. The snow removing tool for the mechanical characteristic analysis, gives the mathematical model of solid ice cutting destruction, the establishment of a new ice failure criterion. The criterion considers the constitutive characteristics of snow, ice and snow that local failure in the weak position, growth for larger cracks, resulting in fracture failure criterion for the establishment of a new. High quality solid ice, clear provides a theoretical basis.
A test rig is set up to measure the cutting resistance of the ice, the ice cutting solid failure test, rationality test proved that the established failure criterion. As the goal, with the minimum cutting resistance setting angle, rake angle, cutting depth for the influencing factors, implementation of the snow parameter analysis test of three factors and five levels of positive rotation. The test proved the correctness of the mathematical model of cutting resistance, availability and further proved that the establishment of failure criterion.
According to the different state of solid ice of different density, and developed a concave milling disc type snow removing key parts, the two parts are the innovation of the split combination of independent servo profiling mechanism, obstacle profiling has good effect, in addition to the net rate is high. The key components for concave disc type snow snow snow passive cutting disc in low density, plate rolling snow, low energy consumption, high efficiency, can complete crushing, shredding, tilting, scraping and push five jobs. The milling type snow removing key components for snow removing knife cutting ice, ice freezing for a film, like high density ice has broken ability strong, with milling, crushing, copying, climbing and other functions.
Design of the four groups of monomer combination concave disc snow testing machine, with speed, snow depth, disc blade angle, angle and direction of the disc as the influence factors, snow resistance, in addition to the net rate, remove the snow block volume as objective function, the four factors and five levels two times by rotating orthogonal test, to determine the optimal parameters of snow removal operations. A comprehensive analysis of theory and experiment to determine the concave disc in addition to the main parameters of key components: snow disc and the direction angle of 13 DEG concave plate disk with a diameter of 400mm, thickness of 3.5mm disc disc, disc blade angle is 20 degrees, concave disk radius is 650mm.
The vertical milling type ice snow key components of the motion analysis and dynamic simulation, simulation of trajectory curve and snow machine actual trajectory curve, verify the correctness of theoretical analysis and simulation. The design of vertical milling type ice snow testing machine, the cutting tool installation angle and speed, spindle speed influence factors in addition, the net rate of removal of snow block volume as objective function, the three factors and five levels two times the rotation regression orthogonal test, determine the test machine vertical milling type snow removing optimal parameter combination.
In the three conditions the implementation of the comprehensive test and milling concave disc type two prototype snow in addition to the quality performance and operating. The experimental results show that the concave disc and milling type snow removing machine are working well, snow removal, high work efficiency, in addition to the net rate is higher than 90%, the parameters setting and the indexes can meet the operation requirements. Snow snow concave disc type key components for density is less than 550kg/m3, the thickness range of ice plate rolling 10~80mm. Milling type snow removing key components for density of 300~750kg/m3 plate thickness is less than 50mm, the ice film ice, especially in ice film density greater than 550kg/m3 the frozen snow. Two prototype snow test for solid snow removing technology and snow removing machinery development provides a theoretical basis.

【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U418.326

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