铜合金直升机旋翼配重构件的金属型铸造及工艺

采用金属型铸造并对铜合金材料进行基础试验和计算,确定了直升机旋翼配重构件的铸造工艺边界参数;利用CAD对铸造工艺参数及铸造工艺方案进行数值模拟.结果表明:经金属型铸造的铜合金密度达到理论密度的99.91%.经金属模铸造成型的铜合金直升机旋翼配重构件满足设计要求:即铸造成型后直升机配重构件的质量偏差为±5 g,曲面变形小于0.2 mm,最大截面厚度偏差为±0.1 mm.经铸造后直升机旋翼配重构件的力学性能为:σb=315 MPa,σ0.2=143 MPa,δ=25%,HB=950.     

直升机旋翼协调加载系统的模型参考自适应解耦控制

研究了直升机旋翼协调加载系统的解耦控制问题.分析了协调加载系统组成结构,建立了电液伺服加载系统数学模型,指出了协调加载系统解耦控制的难点.针对该系统特点,提出了基于GCMAC的模型参考自适应解耦控制策略,采用常规PID控制器作为辅助控制器,GCMAC控制器作为主控制器在线学习理想控制作用,使得耦合系统逼近参考模型,实现解耦控制.仿真表明,该解耦控制策略是有效的,力指令跟踪误差小于4%.     

直升机加载抑制多余力控制研究

针对直升机旋翼加载多余力问题，对耦合模型进行了分析，基于结构不变性原理，讨论了解耦通道的设计，给出了不同的结构和参数配置情况及其多余力消除效果，其结论用于实际系统调试参考。     

旋翼试验台液压伺服控制系统设计

为了满足直升机旋翼试验台的操纵和激振的需求,设计了液压伺服控制系统。该系统由泵站、伺服控制器、伺服动作器等部分组成。系统的额定压力13.5 MPa,额定流量40 L/min,输出频率0～100 Hz。使用结果表明,该系统满足所有的设计要求。     

旋翼飞行机器人的结构设计与动力学建模研究

为了实现旋翼飞行机器人与外部环境交互作业,设计了一种带有机械臂的新型飞行机器人系统,并应用空间算子代数理论对计及刚柔耦合多体系统的旋翼飞行机器人系统进行了递推动力学建模。首先,考虑到旋翼飞行机器人的运动状态、质量比与工作需求,设计了一款通过六旋翼飞行器加装2自由度机械臂的新型旋翼飞行机器人系统。其次,采用空间算子代数理论实现基于刚柔耦合的旋翼飞行机器人正向与反向递推动力学建模。最后,通过编制动力学仿真程序和飞行实验对文中所提算法的有效性进行了验证。结果表明:基于空间算子代数的刚柔耦合递推动力学建模方法计算效率高,仿真结果与实验数据基本吻合,具有一定的工程实用价值。     

小型旋翼气动特性研究

为研究小型旋翼的气动特性,运用CFD方法对旋翼的流场进行数值模拟,通过旋翼表面压力分布、速度矢量、流场流线以及升阻比来详细分析旋翼的流场分布特点和气动特性。设计试验系统并搭建气动测试实验平台,实际测量旋翼的拉力和功耗并验证数值模拟结果的可行性。研究结果表明,旋翼桨尖处压力最大且存在负压区域,桨尖压力梯度最大的地方逸出了桨尖涡。在雷诺数范围0.8×10~5~1.16×10~5内,旋翼翼型在雷诺数约为90 000时的升阻比达到最大。低转速下旋翼的功率载荷较大,在转速约为1 700 r/min时,旋翼的拉力较大同时功耗较小。     

速度同步控制在抑制多余力中的应用

以某直升机旋翼加载系统为例,对被动式力加载系统的多余力抑制进行了研究.提出了传统的结构不变性原理的补偿方案,分析它的优点和不足,进一步提出了利用助力器的控制信号进行速度同步控制、抑制多余力的新方案.仿真和试验结果证明该方案在系统的动态品质、鲁棒性和消扰能力等方面具有相当好的效果.     

形状记忆合金及其在航空工业上的应用(二)

2.2 SMA在旋翼机上的应用直升机旋翼的设计是在悬停条件和前飞操作条件之间找到平衡,但又必须要适应外界环境非常不稳定的空气动力学和动态学条件,由此导致飞机振动大,噪音大,有限的有效载荷和速度,维护费用高以及元部件的使用寿命有限等。传统的直升机旋翼主动控制系统大、重、复杂,但如果换成在电、磁或热刺激下能改变形状的智能材料,将其嵌入旋翼翼片     

含穿透损伤复合材料桨叶结构静强度分析

受弹伤后桨叶结构的静强度、动态特性和剩余寿命等是复合材料直升机旋翼桨叶结构损伤容限设计必须研究的问题.选取某直升机复合材料桨叶靠近桨根的翼段结构,利用CATIA建立三维实体模型,并导入ANSYS软件建立有限元分析模型,分别对翼段不同位置、不同方向的穿透损伤情况进行桨叶结构静强度分析.应用APDL参数化设计语言,开发了计...     

大型直升机旋翼桨毂上、下星板的模锻成形

本文介绍了用100t-m无砧座锤模锻大型直升机旋翼桨毂上、下星板的工艺过程。该项工艺研究目前已用于生产。它结束了我国大型直升机上、下星板模锻件多年来依赖进口的历史,证明了我国在高难度大型锻件技术研究领域上了一个新台阶。     

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.     

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.     

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.     

Rheology Feature of Simple Metal Melt

The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in all measured temperature ranges, whereas for the Bi melt, the curve presents obvious non-Newtonian feature within the low temperature range and at relative high shear stress. The rheology feature of Sb80Bi20 and Sb20Bi80 alloy melts was well correlated with that of Sb and Bi, respectively. It is considered that the rheology behavior of Sb melt plays a crucial role in Sb80Bi20 alloy and that of Bi melt plays a crucial role in Sb20Bi80 alloy.