基于多平台虚拟样机模型的轧机压下系统振动研究

为对轧机压下系统振动特征进行仿真分析,提出基于机液耦合的轧机八自由度动力学模型,采用联合建模仿真的方案,在ADAMS建立了符合八自由度动力学关系的轧机机械模型,同时建立基于AMESim的液压位置模型和基于Simulink的闭环控制模型,通过接口互联搭建了压下系统多平台仿真虚拟样机。设计基于带阻滤波器的控制器对干扰造成的虚拟样机耦合谐振进行抑制。仿真结果表明:滤波器的加入能有效抑制耦合振动对虚拟样机系统稳定性和精度的影响。虚拟样机对轧机振动的研究有一定参考价值。     

基于UG和ADAMS的减速器的虚拟样机设计与仿真分析

介绍了虚拟样机技术的基本概念,运用三维设计软件UG对减速器进行参数化设计和虚拟装配。将减速器模型导入ADAMS软件,完成减速器虚拟样机的设计和对减速器进行运动仿真,仿真结果与理论计算值基本符合,以此证明虚拟样机模型的正确性。虚拟样机技术可以应用在减速器的设计中,降低了开发成本,为减速器的设计提供了一个高效的开发途径。     

空气悬架无杆飞机牵引车动力学仿真分析

提出了一种采用空气悬架的无杆飞机牵引车模型,利用Solidworks建立了空气悬架无杆飞机牵引车整车和波音737-800飞机的虚拟样机模型,并导入ADAMS中添加了相应的轮胎和路面模型。基于ADAMS对无杆飞机牵引车进行了操纵稳定性仿真,得到了该车在装备空气弹簧悬架和钢板弹簧悬架两种情况下车轮定位参数的变化规律,并进行了对比分析,仿真结果证明了空气弹簧悬架在操纵性能上的优越性,通过对无杆飞机牵引系统进行平顺性仿真,得到了飞机前轮质心处的总加权加速度均方根值,该值符合相关标准要求,证明了空气悬架无杆飞机牵引车满足了牵引平顺性的要求。     

陶瓷托辊专用轴承压装机虚拟设计与仿真

针对传统陶瓷托辊专用轴承压装机开发周期长,设计缺陷较多等问题,提出了采用参数化造型软件SolidWorks对陶瓷托辊专用轴承压装机进行虚拟设计的方法,并对陶瓷托辊两侧需要同时压装轴承加工工艺要求及陶瓷托辊专用轴承压装机的主轴系统和夹具装置的机械结构进行了设计。同时利用SolidWorks自带的插件对主轴系统进行了速度、加速度仿真分析以及轴承压装力仿真分析,确定了最大轴承压装力的合理值以及压装速度。虚拟样机的设计为以后样机生产提供了良好的基础。     

数控机床虚拟样机的虚拟加工实现

虚拟加工是对数控机床虚拟样机进行性能测试的内容之一。本文在UG IS＆V环境下建立了一台三轴数控铣床的仿真模型。在该模型的基础上分别对零件加工过程中的刀具路径和铣床运动进行仿真，在虚拟样机上实现了虚拟加工。通过虚拟加工分析，可对设计的机床进行性能预测和评价，进一步完善初步设计。     

考虑切削轨迹可视化的加工线仿真研究北大核心

针对柔性加工线仿真软件鲜有兼具实时数据驱动的设备动作仿真与切削轨迹可视化仿真问题,研究了自动加工线可视化仿真建模要素,提出了基于数据-机构-逻辑的虚拟样机仿真框架与柔性加工线仿真中数据建模方法,通过仿真运动副实现虚拟设备的动作仿真,通过虚拟刀具路径3D可视化模块实现加工线中数控机床刀具切削过程的轨迹可视化仿真,研究了用于虚拟设备逻辑控制的QCode指令系统,设计并开发了面向柔性加工线仿真的虚拟样机原型平台软件,在汽车零部件加工线实例中进行了应用验证,仿真应用表明该虚拟样机软件在兼顾加工线设备动作仿真和刀具轨迹可视化仿真的有效性。     

6-DOF并联坐标测量机碰撞检验研究

使用OpenGL图形库中的图形函数,设计出六自由度并联坐标测量机的虚拟样机.在此基础上对其运动过程采用包围盒算法进行碰撞检验,给出了具体的碰撞检验算法,完成了算法编程并对其进行了仿真.该算法缩短了碰撞检验时间,提高了视景屏幕的刷新率,进一步增强了虚拟样机系统的真实感和用户的沉浸感.     

基于虚拟样机技术的液压支撑平台动力学仿真

通过分析液压系统以及系统载荷的数学模型，在ADAMS环境下建立了某液压支撑平台系统的虚拟样机模型。在虚拟样机的基础上仿真、分析和优化系统动态响应，为实际系统的设计和制造提供了参数依据。     

人体髋关节助力外骨骼的设计

针对半被动式助力外骨骼系统目前普遍存在的驱动机构结构复杂、控制方案繁琐的问题。根据人体髋关节运动生物力学数据,分析了人体行走过程中髋关节角度-力矩的关系特征,并据此设计了一种新型被动式外骨骼驱动机构。利用ADAMS仿真平台对虚拟样机进行了仿真实验,验证了被动式驱动系统设计方案的可行性。最后对样机进行了测试实验,结果表明:该外骨骼助力器能够实现日常运动中的助力功能。     

AJC重要部件仿真模型的研究

阐述了用三维设计软件CAXA实体设计和商用动力学仿真软件ADAMS联合建立复杂机械系统仿真模型的步骤和注意事项,并应用于AJC重要部件的动力学仿真,对该部件的运动过程采用样条函数对未知控制力矩进行采样,实现了该部件的控制运动,为液压控制作准备,对构建一个可分析的较完整的虚拟样机系统有一定的参考价值.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.     

INTRODUCTION TO PATENTS

The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less.     

China Foundry Week 2014

China Foundry Week, hosted by the Foundry Institution of Chinese Mechanical Engineering Society （FICMES） each year, is a large academic event in China. It is one of the ten high-impact activities sponsored by the Chinese Mechanical Engineering Society.     

17th Conference of Hydrodynamic and Electromechanical Control Engineering Call for papers

正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city.     

Formulas of Tension of Continuous Rolling Process

The development of computer controlled continuous rolling process calls for a mathematical expression that can express the inequality condition of "constant flow". Tension is the link of the continuous rolling process. From the condition of dynamic equilibrium, a differential equation of tension is given out. On the basis of the physical rules established from the industrial practice and experimental studies, the law of volume constancy, the linear relation of forward slip and tension, the state equation of continuous rolling, the formula of dynamic tension, and the formula of static tension have been obtained. These formulae reflect the functional relations between tensions, thickness, roll velocity, and time in the continuous rolling process. It is implied that the continuous rolling process is a gradually steady, controllable, and measurable dynamic system. An assumption of predicting the thickness of a steel plate using these tension formulae is also put forward.