Modeling and simulation of crushing process of spiral mining head

1 INTRODUCTIONThe research of mining deep seabed cobalt-richcrust is a hotspot of international oceanology[1].Based on the mining manganese nodule ,lots of re-searches on mining cobalt crust have been madedeeply and many kinds of methods ,such as thei m-proved CLB, mining vehicle +lifting system +surface supporting ship have been put forward.Mining vehicle consists of collecting machine ,tracked treading machine and spiral mininghead[2 ,3].The first step of mining cobalt crust is tocrush…     

Simulation of Cobalt-Rich Crust''s Crushing Process Based on ANSYS

It is a great concern in international oceanology to mine cobalt-rich crust. At present, spiral mining head is regarded as the best crushing scheme. Based on the dynamic model of spiral mining head, the of cobalt crust's crushing process was simulated with the ANSYS software. The material model of Johnson and Cook Plasticity, maximal principal stress failure criterion, and eroding contact arithmetic were selected. At the same time, the influence of cutting depth, feed speed, rotational speed of mining head on torque and force subjected by mining head was taken into account. At last a computer simulation model of crushing process of cobalt crust was established. By analyzing simulation results, the relationships among these controllable process parameters, torque and force can be obtained, which will provide a technical reference for practical mining system.     

基于HJC模型的盾构刀具切削混凝土数值模拟

为了揭示盾构刀具切削混凝土材料时的阻力大小及变化规律,研究Holmquist-Johnson-Cook动态本构模型（HJC模型）参数的确定方法,并据此对混凝土受切削破坏过程进行数值模拟. 设计室内混凝土试块切削试验,根据试验结果对HJC模型参数进行修正,进一步计算分析切削速度与切削深度对切削阻力的影响. 研究表明,基于HJC模型的数值计算结果可基本反映盾构刀具切削混凝土的阻力大小及变化规律;刀具在切入混凝土表面时,法向切削阻力的波动幅度较大,在切削接近试块自由面时会出现剩余材料整块脱落、切削力骤降为0的现象,该过程在数值模拟中相对平缓;在相同条件下,率效应参数主要影响法向切削阻力的波动幅度,损伤参数则同时影响法向切削阻力的平均值与波动幅度;法向切削阻力随切削速度呈指数形式增加,随切削深度呈线性增加;HJC模型可反映混凝土压碎破坏与材料应变率间的关系及法向切削阻力随深度的线性叠加效应.     

Model test of the cutting properties of a shearer drum

According to similarity theory, we carded out a dimensional analysis of the shearer drum correlation parameters and built similarity criteria. Based on these, similarity models of shearer drums were developed. Simultaneously, based on an estab-lished cutting testbed of the coal and rock, cutting tests of different pick arrangements of the drum models were carried out, where the compressive strength of the analogous cutting material was 2.48 MPa and the drum rotary speed 67.5 r/min. The variance, the mean values, maxima and mean maxima of the torque load were analyzed for different type drum models. Moreover, the relation-ships between the type of pick arrangements and the cutting lump coal percentage were studied. The results indicate that the load fluctuation of the sequence drum is larger than that of the punnett square drum in the cutting process and the lump coal percentage and economic benefits of the sequence drum are inferior to the punnett square drum. We conclude that the punnett square drum is superior to the sequence drum.     

基于ADAMS的ROV采矿车近海底着地虚拟仿真

为了研究ROV采矿车在深海钴结壳开采中的作业性能,论证ROV用于深海采矿的可行性,为ROV深海采矿车作业进行预报,借助了多体动力学仿真软件ADAMS,运用了虚拟样机技术对ROV采矿车的近海底着地过程进行动力学仿真．首先应用SolidWorks软件建立起ROV采矿车的三维实体模型,并导入了机械系统动力学分析软件ADAMS中建立虚拟样机,在深海环境下对该虚拟样机近海底着地进行了多体动力学仿真,其结果表明ROV采矿车在近海底着地时切削头与地面存在着碰撞,该碰撞是强烈的．对此提出了一种改进策略,让采矿车在推进器控制下实现0速度着地,切削头与地面的碰撞大大减轻,该控制方法效果良好．     

车削加工过程中切削力的试验研究

运用DEFORM仿真软件对金属切削过程进行仿真实验,以金刚石为切削刀具,AISI52100淬硬钢为工件材料,采用正交仿真实验分析切削速度、进给量、切削深度对切削力的影响规律,并给出实验范围内的最优加工参数组合,当切削速度vc=120 m/min、进给量f=0.10 mm/r、切削深度为时ap=0.1 mm,切削力达到最小。最后运用回归分析方法建立切削力的经验模型,对得到的经验公式进行显著性检验,证明经验公式的可信性。     

滚轮平盘牵引式无级变速器自适应变速机构动力学分析

无级变速器（CVT）是一种理想的机械传动方案,现代工业和车辆技术的发展,希望CVT的变速机构对于负载改变能够实现自动/自适应变速,本文针对典型的同轴移动类牵引式CVT—滚轮平盘牵引式CVT,提出了一种基于螺纹-弹簧力封闭的自适应变速机构,并对其进行动力学研究。首先,给出具有螺纹-弹簧式自适应变速机构的滚轮平盘牵引式CVT结构模型;然后,分别对该CVT进行了运动学分析并给出运动学参数计算模型,根据赫兹接触理论建立其牵引点接触模型,采用分离体分析法建立了其动力学模型;最后,重点分析了变速过程中滚轮与平盘之间侧滑力的变化规律,分析出滚轮自适应负载变化的变速运动规律,研究了弹簧刚度系数对变速过程的影响,并对自适应变速过程的滚轮偏移规律进行了仿真实验验证。结果表明：（1）自适应变速过程中,当侧滑率系数大于0.55时,侧滑力大小基本恒定;（2）自适应变速过程为一振动过程,且变速机构中弹簧的刚度系数和负载力矩会直接影响变速响应时间和变速稳定时滚轮侧滑量大小;（3）在同样大小的负载作用下,不同的初始负载条件会影响到变速振动的振幅,但对于变速稳定时滚轮的偏移量无较大影响;（4）自适应变速过程的滚轮偏移规律的仿真结果与计算结果趋势吻合,但变速稳定时间有明显区别,仿真结果更接近实际情况。     

Optimization methods of cutting depth in mining Co-rich crusts

For optimizing the cutting depth of spiral drum type cutting head,the relations among collecting ratio,interfusing ratio of mullock and cutting depth of the mining cobalt-rich crusts in ocean were discussed.Furthermore,the multi-extremum problem about cutting depth was analyzed in mining at a certain interfusing ratio of mullock.Through introducing genetic algorithm(GA),the cutting depth-control problem when the collecting ratio is maximized by controlling the interfusing ratio of mullock was solved with global-optimization-search algorithms.Then optimization theory for cutting depth in mining cobalt-rich crusts by GA,and computer programming were given to realize the algorithm.The computation result of actual data proves the validity of this method.     

虚拟样机技术及其在ADAMS中的应用

阐述虚拟样机技术的概念、特点及应用，对著名的虚拟样机分析软件ADAMS的功能进行介绍，最后给出虚拟样机技术在ADAMS中的应用实例。     

基于光栅扭矩转速传感器动态测试系统设计

为了减少一般测试系统由于很多传动链而带来的测试误差,提出同轴集成传动,同轴光栅扭矩/转速传感器测试系统.不仅能够通过光栅实现高速高精度转速测试,而且利用同轴上两个光栅的信号差动性实现了高精度动态扭矩测试.运用高速数据采集卡PCI-1784进行了四轴信号同步采集,通过LABview软件搭建计算机虚拟仪器测试平台;在提取扭矩信号方面,还提出了软件相关分析鉴相法.     

滚切端铣刀的切削力试验研究

本文研究滚切端铣刀的切削力变化规律。针对滚切端铣刀的加工特点,改变刃倾角、刀片直径及切削用量,分别测量切削力,并给出切削力的变化规律。试验研究结果表明,铣削深度对切削力的影响较大,进给量的影响次之,刀片直径、刃倾角及铣削速度对切削力也有影响。本课题的研究结果,将有助于滚切端铣刀具的应用和推广。     

基于铣削力突变的拼接模具硬态铣削工艺优化

针对刀具磨损过快和加工稳定性下降的问题,进行了淬硬钢Cr12MoV拼接模具铣削过程中铣削参数和路径优化的研究.通过试验研究揭示了刀具铣削方向、切削速度、进给速度及切削深度对拼接处铣削力突变的影响规律,并借助多因素试验得到了铣削条件对铣削力突变影响的主次因素.为降低铣削力突变对铣削过程的影响,以铣削力突变最小为目标进行了正交试验研究,并在此基础上得到了优化后的铣削参数组合.研究成果可为拼接模具铣削工艺优化提供有意义的参考.     

压铸镁合金AZ91D钻削力经验公式

采用正交试验的方法对压铸镁合金AZ91D进行了钻削试验,用多元线性回归法对试验结果进行了处理,建立了压铸镁合金AZ91D的钻削力与扭矩的经验公式。由经验公式可以确定:对钻削力和扭矩影响最大的是钻头直径 d,进给量 f次之,切削速度 v的影响最小。因此在实际生产中可以采用提高转速的办法来提高加工效率,减少能耗。     

高能效高速稳态铣削参数优化

为了提高铣削加工的能量利用率,提出了一种以无颤振切削为约束条件,以能量利用率为优化目标的铣削参数优化方法.基于机床的能耗特性,建立了提高能量利用率的无颤振铣削参数优化模型.利用切削稳定域图确定主轴转速的优化区间,利用切削力、切削功率、切削速度等条件确定切削深度、切削宽度及进给速度的优化区间,并通过合理选择各参数的优化步长快速获得切削参数.以五轴雕铣机为实验机床,45#钢为切削材料进行了验证试验,结果表明,该参数优化方法使能量利用率得到了较大提高.     

变速切削系统的振动响应特征

研究了变速切削系统的振动响应特征，理论分析和实验结果均表明，在发生再生型颤振时，变速切削系统的振动响应和动态切削力的频率随时间的变化规律和机床主轴转速随时间的变化规律相同；动态切削力为一宽频的激励信号，振动响应为一窄带的响应信号；动态切削力和振动响应的包络变动周期与机床主轴的变动周期相同     

Strategy to control crawling vehicles with automated mechanical transmission

In order to move vehicles with automated mechanical transmission (AMT) a little bit of distance, such as reversing into or moving in a garage, a control strategy for crawling vehicles was proposed. Based on the dynamic analysis of vehicle starting process and requirements of crawl driving for the vehicle,a control strategy of the clutch was designed. The strategy increased the slipping friction torque first and then decreased it, in order to realize the crawl driving. The speed increased by the engagement of the clutch, and then the clutch turned to disengage to the half disengage point, when the speed met the requirements. Based on the control strategy, a control software was designed. In the end, the software was tested on a vehicle with AMT. The lowest steady vehicle speed was reduced to 40% of the original value, which was set in the control strategy.     

振动钻削过程监控系统的研究

介绍了一种麻花低频复合振动钻削在线监控系统，该系统以刀具状态为主要监测对象，以切削力为监测参数，具有预报刀具破损、监测刀具磨损，并在异常状态下适时地控制切削过程等功能。     

基于虚拟样机的减速器动力学分析

通过三维CAD软件SolidWorks创建了减速器的参数化实体模型;利用Parasolid文件接口在AD-AMS中实现了减速器虚拟样机的构建.基于虚拟样机的建模和仿真为机械设计提供了依据,提高了设计效率.     

高速铁路双块式无砟轨道车辆荷载动态传递特征

为研究车辆荷载在无砟轨道中的传递特征,建立车辆-双块式无砟轨道耦合动力学模型,对车辆荷载在无砟轨道主体结构内的动应力和振动加速度传递规律进行研究,并对行车速度、结构尺寸及层间接触状态等影响因素进行分析. 结果表明:车辆荷载的主承载区分布在道床板内,垂向动应力峰值在0.1 m深度之内衰减73%;车辆荷载的主振动区主要分布在道床板内并传递至支承层,垂向加速度峰值在0.1 m深度之内衰减89%;轨道结构动态受力及振动响应均随行车速度的增加而增大;适当减少轨道结构宽度,对其受力和振动特性影响较小. 无砟轨道结构层间插入隔离层,可减小轮轨动力响应及轨道结构动态受力,但结构层间垂向加速度明显增大,插入弹性层,可减小钢轨垂向加速度,但对轮轨动力响应、道床板和支承层动态受力及振动特性影响较小. 所得结论可为无砟轨道设计和优化提供理论参考.     

Method to determine installing angle of conical point attack pick

In order to obtain the determining method of the installing angle and decrease the performance indices (cutting force and wearing rate) of the pick, the relationships among the installing angles (impact angle, inclination angle and the skew angle) were studied, and the static model of installing angles of the pick was built. The relationships among the impact angle, the tip angle of pick and the kinematics parameters of the pick were built, too. Moreover, the mechanic models of the maximum clearance angle and the wearing angle of the pick were set up. To research the relationships of the installing angles and the change law of the wearing angle along with the kinematics parameters, the simulation was done. In order to verify the correctness of the models, the cutting experiments were done by employing two picks with different pick tip angles. The results indicate that, the cutting force is the smallest when the direction of the resultant force of pick follows its axis, and the relationship derived among the installing angles should be satisfied. In addition, to decrease the cutting force and the wearing of the pick, the tip angle of pick should not be larger than the half of the difference between the minimum wearing angle and the impact angle of the pick, and the clearance angle must not be less than zero.