捕捉缓冲机构刚柔耦合多体动力学仿真研究

大部分动力学仿真分析采用的都是刚性构件，在现实生活中把构件看成刚性系统来处理可以满足要求，但这忽略了构件变形的影响。为了得到更真实有效的数据，就必须把模型的部分构件看作柔性体来处理。为研究某捕捉缓冲机构的动力学性能，从理论层面介绍动力学的研究方法和刚柔耦合研究的整体思路，并利用ANSYS和ADAMS导出的MNF文件和LOD文件，从刚柔耦合多体动力学的角度对捕捉缓冲机构进行了综合实验分析和对比。通过刚柔耦合研究实现了动力学和结构学的联合仿真，得到了更精确的仿真数据，在获得动力学测量数据的基础上又获得了结构学数据，使仿真结果更为全面，同时也为对结果要求较高的多体动力学工程仿真问题提供了参考。     

柔性输电线-带电作业机器人刚柔耦合特性分析

输电线路带电作业机器人通过双轮行驶于高压电缆,刚性的机器人系统和柔性的输电线路之间构成了复杂的刚柔耦合系统,特别是在刚性系统和柔性系统的轮线接触处表现出较强的非线性复杂耦合特性。为保障机器人作业过程的稳定性,获取较好的作业动态性能,分别建立了柔性导线、刚性机器人以及柔性导线-刚性机器人的耦合动力学模型。基于该模型,在ADAMS中分几种不同典型工况对带电作业机器人线上作业行为的动力学特性进行了仿真研究。通过仿真特性曲线一方面验证了刚柔耦合动力学模型的有效性,另一方面通过仿真模型得到了合适的机器人动力学参数,从而实现机器人作业优化与控制。最后在带电线路进行现场引流板紧固作业试验,结果也验证了所提出的刚柔耦合动力学模型的工程实用性。     

四辊轧机辊系刚柔耦合动力学建模研究

板带轧机的工作稳定性取决于系统的动力学特性,其中轧辊沿轴线方向的弯曲变形运动是影响板带厚度和表面质量的主要因素。几种运动形式相互影响、耦合作用,令轧机辊系成为一个复杂多变量动态系统。为综合考虑轧制过程中轧辊不同振动形式之间的耦合效应,同时考虑工作辊动特性与轧制外载荷动态增量之间的相互作用关系,本文分别建立了辊系刚柔耦合动力学模型、轧机系统刚性振动耦合动力学模型和轧制变形区耦合动力学模型。通过建立的四辊轧机刚柔耦合动力学模型体系,对轧制过程进行动态控制,仿真分析了轧制过程中轧机辊系和变形区内轧件的动力学特性。     

航空发动机叶片焊接机床刚柔耦合建模研究

利用有限元分析软件ANSYS Workbench对机床进行了静力学分析,初步了解了机床的变形情况。根据变形情况,利用动力学分析软件ADAMS对易变形及振动构件柔性化建立了刚柔耦合虚拟样机。在虚拟样机中对焊枪的平动、加减速、高速运动等不同的运动形式进行了仿真,研究分析了滑枕和丝杠的变形和振动情况,对刚性模型和刚柔耦合模型圆弧轨迹进行了对比。结果表明,刚柔耦合虚拟样机能够更真实精确地进行运动学、动力学分析,对机床的设计、改进和误差补偿有重要意义。     

基于刚柔耦合的数控机床动态特性分析

在所开发的五坐标龙门数控机床虚拟样机的基础上,对其关键部位--横梁进行柔性化,建立了整机的刚柔耦合多体动力学模型,分析讨论横梁的柔性效应对机床运行稳定性的影响.结果表明:基于刚柔耦合模型的仿真分析更为准确地反映了机床的动力学特征,为最终实现机床结构优化设计提供可靠的理论依据.     

起-停式定宽压力机刚柔耦合模型的动态仿真分析

为研究起-停式定宽压力机柔性体部件对机械运动精度的影响,分别应用Solid Works和ANSYS软件建立定宽压力机的三维刚体系统模型和侧压连杆的柔性体模型,并在动力学仿真软件ADAMS中采用替换法建立刚柔耦合虚拟样机模型,通过仿真分析,得到了锤头的行程、速度和加速度等运动学参数,侧压连杆与滑架和曲柄之间的接触力分布,侧压连杆的应力及变形情况,并对多刚体和刚柔耦合模型的仿真结果进行了对比,结果可知,刚柔耦合模型更能反映机构的真实运动,为其动态性能的评价和优化提供参考。     

上料桁架机械手刚柔耦合运动特性研究

为保证桁架机械手在高速及大行程工作范围中满足高精度、稳定可靠及大承载性能要求,采用刚柔耦合动力学分析方法对其运动特性进行分析。在桁架机械手的基本结构及工作流程的基础上,通过SolidWorks-RecurDyn平台建立多刚体动力学模型,利用Hertz理论计算齿轮齿条啮合刚度以及滑块导轨接触刚度来保证模型建立的准确性。并利用RecurDyn-ANSYS完成横梁(RFlex)及滑台(FFlex)的柔性体建模工作,最终建立桁架机械手刚柔耦合动力学模型。通过对桁架机械手刚柔耦合运动特性分析,研究关键部件柔性化对桁架机械手末端执行器运动精度的影响,通过仿真发现运动过程中等效质量块质心的实际轨迹与理想轨迹在X、Y、Z方向的差值分别为±0.06、±0.72、±0.06 mm,以此评定其运动精度为±0.72 mm,不满足±0.2 mm的技术要求。因此,采用加固结构方法,通过对横梁横截面进行改进。结构改进后的运动精度为±0.17 mm,满足了技术要求。     

下肢外骨骼康复机器人刚柔耦合分析与仿真

下肢外骨骼康复机器人的组成连杆在辅助人类运动的时候会因为自身柔性发生弹性变形,会影响到整个行走轨迹的位置精度和控制的实时性与准确性。针对所设计的下肢外骨骼康复机器人,首先通过步态仿真验证模型的正确性,然后建立其刚柔耦合动力学模型。在刚柔耦合动力学模型的基础上,通过ADAMS和ANSYS完成摆动期阶段内的刚柔耦合动力学联合仿真,得到其动态变形误差数据。结果表明：在Y方向、Z方向位移误差和整体位移误差分别在-38～3.6 mm、-7.5～3 mm、-6～14.5 mm内波动,与其他两方面相比,Y方向上的位移误差最大,在误差允许的范围内。验证了下肢外骨骼康复机器人刚柔耦合模型的正确性与合理性,为后续的结构优化和控制系统的设计提供了参考依据。     

多电机驱动的双辊夹持旋压成形装置的动力学仿真

对双辊夹持旋压成形装置进给驱动系统进行了动力学分析,得到了装置进给驱动系统的动力学模型。利用多体动力学软件ADAMS和有限元软件ANSYS对多电机驱动的双辊夹持旋压成形装置进行了多刚体模型和刚柔耦合模型的动力学仿真,通过比较装置夹具和旋辊头运动轨迹的理论结果和仿真结果验证了所建立模型的正确性。仿真过程充分考虑了滑块与导轨之间的等效阻尼、刚度和摩擦等非线性因素以提高仿真精度。刚柔耦合模型仿真结果显示,旋辊头进给速度波动的幅度为±0. 065%,周期为0. 42 s,夹具进给速度波动的幅度为±0. 4%,周期为0. 71 s,表明丝杠的弹性变形会影响装置进给驱动系统的运动精度。     

RV减速器传动误差特性分析与实验研究

以高精度RV-80E减速器为研究对象,针对其结构特点,利用ADAMS多体动力学仿真软件建立RV减速器刚柔耦合模型,并验证模型的正确性。采用刚柔耦合模型设计了多组不同误差的仿真样机,并通过仿真分析了不同误差因素对整机传动精度的影响。分析不同的误差组合方式,得出正等距和负移距、负等距和正移距的误差组合可以有效地减小传动误差对整机传动精度的影响。通过实验测试,分析了国内外RV减速器传动精度的差异。分析了RV-80E减速器传动误差和误差频谱,确定了二级传输误差为影响传动精度的主要原因。研究结果为减速器批量化生产提供了参考。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

The Mirror with Patterns of Auspicious Animals and Grapes——Exquisite cast mirror and the technology of surface tin-enrichment by rubbing-in and infiltration of tin-rich powder

<正>Bronze mirrors were used by the Chinese people before the introduction of the glass mirror.Only after it was replaced by the glass mirror did the bronze mirror gradually retreat from people's lives.Different styles of bronze mirrors were made in different historical periods,particularly in the Warring States Period,the Han and Tang Dynasties,which were the three peaks of the development of bronze mirror arts in ancient China.The casting techniques were exquisite.The surface of the bronze mirror was smooth and bright enough to reflect one's image,and there were scarcely any casting defects on the mirror surface.On the back of the bronze mirror,there were rich depictions of Arts and Humanities,and the ornamentations were also     

The 9th China International Diecasting Congress & Exhibition

The 9th China International Diecasting Congress ＆ Exhibition was held on July 22-24, 2014 at Shanghai New International Expc Centre. This exhibition was the most successful over the years, with over 6890 visitors and 155 exhibitors, and the exhibition area increased by 30% from 9,500 square meters in 2012 to 12340 square meters. Die casting enterprises from a total of 24 countries and regions, including China mainland, Chinese Taiwan and Hong Kong, South Korea, Japan, Germany, India, Thailand, Malaysia, the United States, Russia, Australia, Iran, Ukraine, Brazil, Colombia, Singapore, Austria, Canada, Croatia, France, Turkey, United Kingdom, Vietnam, attended the congress and exhibition.     

Introduction of the Fluid Control Engineering Institute of Kunming University of Science and Technology

正The Fluid Control Engineering Institute of Kunming University of Science and Technology was set up in 1996.The researches of institute concentrate on electro-hydraulic(pneumatic)servo/proportional control and hydromechatronics.The Institute is committed to research and development of electro-hydraulic control of high-end technical equipment in ferrous metallurgy refining produc-     

RARE METALS Volume Contents

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Antimony Induced Crystallization of Amorphous Silicon

Antimony induced crystallization of PVD (physics vapor deposition) amorphous silicon can be observed on sapphire substrates. Very large crystalline regions up to several tens of micrometers can be formed. The Si diffraction patterns of the area of crystallization can be observed with TEM (transmission electron microscopy). Only a few and much smaller crystals of the order of 1μm were formed when the antimony layer was deposited by MBE (molecular beam epitaxy) compared with a layer formed by thermal evaporation. The use of high vacuum is essential in order to observe any Sb induced crystallization at all. In addition it is necessary to take measures to limit the evaporation of the antimony.     

A CUMULATIVE FATIGUE DAMAGE RULE UNDER THE ALTERNATIVE OF CORROSION OR CYCLIC LOADING

Fatigue damage increases with the applied loading cycles in a cumulative manner and the material deteriorates with the corrosion time. A cumulative fatigue damage rule under the alternative of corrosion or cyclic loading was proposed. The specimens of aluminum alloy LY12-CZ soaked in corrosive liquid for different times were tested under the constant amplitude cyclic loading to obtain S-N curves. The test was carried out to verify the proposed cumulative fatigue damage rule under the different combinations among corrosion time, loading level, and the cycle numbers. It was shown that the predicted residual fatigue lives showed a good agreement with the experimental results and the proposed rule was simple and can be easily adopted.