Based on the working conditions of the variable center distance non-circular gear pair, this research provides the rounding theories and methods for the theoretical pitch curves of the gear pair, including establish the working conditions model of the variable center distance non-circular gear pair; group and classify the instantaneous working conditions and the instantaneous meshing arcs; design rounding algorithms for instantaneous meshing arc group category 1, 2, and 3; and propose the dynamic allocation strategy for distribute the total rounding amount on each pair of instantaneous meshing arcs. Finally, with the help of a variable center distance non-circular gear pair example, this research successfully proved the correctness and effectiveness of the above rounding theory and method, achieve the goal of rounding the theoretical pitch curves of the variable center distance non-circular gear pair.

影响V形工件弯曲回弹的工件尺寸、力学性能、负载条件和材料各向异性等众多因素相互耦合,表现出高度复杂的非线性,从而导致回弹预测结果的不确定性.把板料回弹后的张开角和圆角半径作为目标优化函数,将支持向量机模型部署到顺序向前筛选算法中以高效筛选出最优的特征变量参数子集,从而提高弯曲回弹模型预测结果的精度与可靠性.有限元分析和实验结果的对比验证了算法模型的可行性.

针对某典型小型行星减速器输出轴组件,对其销轴与行星架的过盈配合展开研究.首先根据理论计算得到过盈量的初始范围;再利用Ansys Workbench软件模拟分析设计参数对过盈装配的影响,其中重点分析了过盈量和摩擦系数对接触压力、等效应力和压装曲线的影响关系.研究发现过盈量对过盈配合的影响最大,摩擦系数对接触压力的影响可以忽略不计,在此基础上根据仿真结果对理论计算的初始过盈量范围进行优化,得到最佳过盈量范围为0.004～0.008 mm;最后将销轴结构进行改善,结果表明所提出的阶梯销轴不会改变联接的可靠性,且能改善结构应力情况,提升压装质量,为小型行星减速器输出轴组件的设计提供参考.

研究一种桥式卸船机在实际工作过程中,其主要运动参数(料斗运行速度及切入角度)对取料过程的影响,通过不同的参数设置,在EDEM中进行仿真,得到结果如下:料斗运行速度及切入角度对挖掘阻力有较大影响.在实际过程中,应当把料斗切入角度控制在40°～60°之间,当需要以不同的角度挖料时,需要控制料斗运行速度在1.5 m/s～1.8 m/s之内,此时可以获得较高的资源利用率.EDEM具有传统计算不具备的优势,能够研究速度参数对实际取料的影响.

研究雅克比旋量模型的建模原理及公式的物理意义,分析旋量模型的取值缺陷,并结合蒙特卡洛法进行优化.其优化内容包括优化旋量模型代入至雅克比旋量模型时的计算原理;增加旋量模型中矢量的约束条件;优化取值范围内的随机数生成方法,使旋量模型获得的随机变量与真实情况符合度更高.另外,将优化后的三维公差模型应用于板簧机构上,计算汽车起重机板簧卷耳孔的空间位姿变化,以此提高底盘装配时车轴孔同轴度的可控程度.

从双吊具单臂架门座起重机的总体构造、起升机构、吊具系统、跟随系统、吊具减摇系统等方面系统介绍了其关键技术,通过实际作业应用效果检验,表明集装箱双吊具单臂架门座起重机方案可行、综合性能良好,可大幅提高生产效率.

The size increasing of container cranes has resulted in vulnerability to seismic loads. To explore the response characteristics and failure mode of large container cranes under earthquake loads is one of the problems needed to be solved urgently. Currently, due to the limitation of test conditions, it is impossible to conduct seismic dynamic test for the prototype of the container cranes. Finite element simulation analysis is the most widely used method, but the reliability of this method and its results remains to be discussed. In this paper, finite element modeling of a large container crane structure is carried out, and a series of time-history analyses under different seismic load conditions is performed. Based on the shaking table seismic simulation tests for the scaled model, the seismic dynamic characteristics of the container crane structure are comprehensively analyzed. The analysis of test results can provide a reference for seismic research, vibration reduction and isolation treatment and model test of container cranes.

国内对木片的巨大需求,带动了相关产业的发展,但随之而来的问题是港口木片卸船设备的作业效率不能满足高效的发展需求.散货木片具有含水量大、流动性差等特点,堵塞、板结是木片卸料过程中最大的问题.为研究漏斗卸料时木片的流动特性,使用离散元分析软件EDEM建立了不同结构形式的漏斗,模拟仿真了漏斗内木片卸料的流动状态.针对木片的物理特性,从漏斗斗壁角度、漏斗栅格尺寸、漏斗栅格形状以及与后续带式输送机带速的配合等方面进行分析,从而选出最优方案,使整个系统合理、可靠、高效.

基于轮式移动装船机的设计方案及参数,对装船机进行总体设计;根据轮式移动装船机的臂架结构特点,提取其特征参数,然后运用Ansys的APDL语言建立臂架的参数化模型,并对臂架结构进行有限元分析;最后运用Ansys软件和优化设计技术对臂架结构进行优化分析,在满足设计要求的情况下,实现臂架的经济性和可靠性.得出结果如下:由于臂架下铰接距进料口较近,其受力也较大,臂架头部相当于悬臂梁且悬挂着溜筒,臂架最大应力出现在下铰接处,最大变形量出现在臂架头部;臂架结构采用变截面设计可以大大降低结构总重.

The Discrete Element Method (DEM) requires input parameters to be calibrated and validated in order to accurately model the physical process being simulated. This is typically achieved through experiments that examine the macroscopic behavior of particles, however, it is often difficult to efficiently and accurately obtain a representative parameter set. In this study, a method is presented to identify and select a set of DEM input parameters by applying a backpropagation (BP) neural network to establish the non-linear relationship between dynamic macroscopic particle properties and DEM parameters. Once developed and trained, the BP neural network provides an efficient and accurate method to select the DEM parameter set. The BP neural network can be developed and trained for one or more laboratory calibration experiments, and be applied to a wide range of bulk materials under dynamic flow conditions. (C) 2018 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.

针对块状颗粒在伸缩溜筒下料过程中的破碎问题,运用离散元Hertz-Mindlin with bonding粘结接触理论,建立煤炭颗粒破碎模型,基于岩石破碎的能量学说,采用虚拟标定法确定粘结参数.根据离散元仿真研究煤炭颗粒在伸缩溜筒中的输送及破碎情况,对伸缩溜筒系统提出结构优化建议.结果表明,改进后的伸缩溜筒系统能够有效降低下料过程中的块煤破碎情况,降低运输折损.

介绍桥式链斗卸船机的主要部件功能及其作业方式,卸船机通过大车行走与料斗的提升进行直线段取料,通过链斗的摆动实现分层取料,为了使生产率保持恒定值,对卸船机的料斗起升速度和大车行走速度二者的匹配推出了计算公式,并在取料能力最大的条件下对工作速度匹配进行了优化,在保证卸船能力最大和生产率恒定的条件下使大车行走速度和料斗速度在工作中达到最佳组合.

With the rapid development of cranes, crane teaching aids cannot follow up with new products in real time, and the teaching cost is high and the space utilization rate is low. In order to solve these problems, we used SolidWorks and 3ds Max to carry out mechanical modeling in the virtual environment. Based on the Unity3D development engine, we designed a virtual simulation teaching evaluation system for cranes, which completed the design of modules for cognitive teaching, maintenance, fault repairing and teaching assessment. The system takes advantage of virtual technology’s features of immersion, interaction and imagination. Therefore, it solves the problem of the slow update of teaching aids in the teaching process of cranes effectively, saves teaching costs greatly, overcomes the traditional teaching boring shortcomings, and improves the efficiency of port machinery education. And It plays an important role in promoting the application of virtual reality technology in education and training.

There are many factors influencing springback of high strength U-shaped bending parts,such as workpiece size,mechanical properties and load conditions,which make bending springback of high-strength bending parts be difficult to control. The minimum bending radius R and the springback angle α were taken as two objective functions. Firstly,supervised gaussian process latent variable model( SGPLVM) was used for variable selection and dimensionality reduction,the least squares support vector machine( LSSVM) model for U-shaped bending part was constructed. The prediction results of SGPLVM-LSSVM were compared with SVM,FEM prediction results and actual engineering parts to verify the feasibility of the proposed model.

In this paper, the particle dynamics and free surface in a simplified disc device are studied using experiments and the Discrete Element Method (DEM). Two different kinds of free surface formula for the motion of particles in a disc device are derived and calculated. The disc rotational speed, particle filling rate, and particle materials are used as three experimental control parameters, and the experimental results are compared with the numerical calculation results. In order to obtain the dynamic distribution of particles, the influence of contact friction parameters are discussed by the DEM simulation. Besides the operating conditions, it can be observed that the particle material properties play an important role in particle dynamic distribution and DEM granular flow prediction. The results prove a feasible prediction of the particle free surface physical models, which also provides a method and theoretical basis to predict the particle flow characteristics in the vertical screw conveying.

Given the effects of granular fluidity on the performance of the vertical screw conveyor, a numerical simulation based on discrete element method was conducted to analyze the motion law of the granular in the transport process with periodic boundary condition. By comparing the impacts of different screw rotational speeds on the distribution of granular rotation angular velocity, the accuracy of tradition angular velocity models were evaluated and then a correction of model was performed. Research results show that: the distribution of granular angular velocity was not only related to its radial position, but also to its vertical height, and an obvious defects existed in the tradition models; the relative error between the corrected model and simulation results was under 7％, which proves the corrected model to be better applicability. It makes a great sense to predict the performance of the vertical screw conveyor more exactly.

引入了一种特征提取方法——主成分分析法(PCA),通过降维,把高维的决策变量映射到低维空间,得到主成分(主要的决策变量),简化了模型,提高了效率,并结合极限学习机(ELM),使用一种改进的带精英策略的非支配排序遗传算法(NSGAⅡ),对建立的多目标优化模型进行求解,得到Pareto最优解集.

The use of port shore electricity when the ship is in port, which has a very important environmental and economic value. Ship charging pile is an important part of shore power system, according to the characteristics of the Yangtze River inland port, a new type of intelligent low-voltage shore power charging pile is designed. The overall structure and appearance of the charging pile are designed in detail, meanwhile, control system diagram and appearance design drawing of the ship charging pile are drawn out. In this paper, the design of the main circuit and the PLC control system of the charging pile are put forward, which is based on the specific function of the ship charging pile. At the same time, the main technical indexes and parameters of the low voltage shore power charging pile are presented. At last, the main function of low-voltage shore power charging pile is introduced.

In this paper, aiming at the nonlinear and non-stationary characteristics of the fault vibration signal of roller bearing, a hybrid fault feature extraction method based on improved Local Mean Decomposition (LMD) and spectral kurtosis is proposed. Firstly, the conventional LMD is improved by the Akima interpolation method. Then the original vibration fault signal is decomposed through Akima LMD (ALMD) into several product functions (PF) components carrying physical meaning. Secondly, the grey relational grade analysis and mutual information theory are combined to filter and acquire the PFs which contain the main fault signature. Lastly, these specific PFs are analyzed by spectral kurtosis and envelope demodulation method in order to extract the fault feature frequency. And the proposed hybrid method is verified by actual engineering signal.

In view of the problems in potential energy recycling and the detection of lifting mechanism of the portal crane, the paper analyzes energy flow use and loss of the lifting mechanism during operation , describes the energy efficien-cy computational formula for the entire operating cycle of the lifting mechanism , introduces the detection method for poten-tial energy recycling , and gives specific procedures of the detection and wiring diagram .With the hoisting mechanism of MQ4040 port portal crane as the test prototype , the energy efficiencies before and after installing the energy-saving device are compared.The result shows that , after the energy recovery unit is installed , the energy efficiency index improves by 41.4%, indicating significant energy-saving effect .