金属管、板材液压成形工艺

主要针对液压成形技术在金属管材、板材成形中的发展与应用作了简要的介绍。认为目前的板料液压成形已逐渐从航空航天以及电子行业扩展到民用汽车以及家庭用品等行业，而管料液压成形已脱离实验阶段，正在进入汽车工业领域。可以预见，液压成形工艺必将在未来的汽车“轻量化”以及产品“精密化”运动中得到广泛的应用。     

复合管液压成形装置及残余接触压力预测

针对现有复合管制造工艺中存在的问题，研制开发了一种焊接不锈钢衬里复合管液压成形装置，介绍了该装置液压成形系统的工作原理及技术特点。阐述了复合管液压成形过程的原理，并采用弹塑性理论分析了其在液压成形过程中内管及外管的应力应变状态。推导出了复合管残余接触压力与成形压力之间关系的理论计算公式，通过实验对公式进行了验证。结果表明该装置结构及其计算方法适于工程应用。     

板材液压成形技术与装备新进展

随着板材零件向大尺寸、薄壁、深腔、复杂曲面以及难变形材料方向发展,具有低成本、高柔性的板材液压成形技术在航空、航天、汽车等制造业受到高度重视,并面临新的机遇和挑战。介绍板材液压成形技术的发展现状,重点介绍近年发展的径向主动加压充液拉深、预胀充液拉深、正反向加压充液拉深、双板成对液压成形和热态液压成形技术。分析国内外板材液压成形技术在汽车、航空航天等领域的应用现状,综述板材液压成形装备的研制进展,介绍正在研制的世界最大的吨位为150 MN、液体容积为5 m3的液压成形装备,对板材液压成形技术的发展趋势进行展望。     

板料液压成形的研究现状

介绍了板料液压成形的原理和方法,对板料液压拉深成形、管材液压胀形和壳体液压成形这三种典型的板料液压成形工艺进行了详细分析,并对板料液压成形的发展趋势进行了展望。     

管件液压成形技术应用进展

管件液压成形技术作为轻体构件的先进制造技术，近几年得到了飞速的发展。本文介绍了该技术的成形原理和工艺分类，以及主要优点和适用领域，并列举了采用管件液压成形技术所成形的典型零件，指出了管件液压成形技术未来发展的广阔前景和显著的经济效益。     

液压成形管件中心轴线抽取算法

管材液压成形技术是一个相对新颖的技术，其在应用过程中仍然有许多问题需要研究和解决。基于有限元法的管材液压成形数值模拟技术发展的时间更短，有待进一步研究和发展。针对这种发展要求，提出了管材液压成形数值模拟中分析模型的构造方法，并且重点介绍了逆向构造中管件中心轴线的抽取算法即边界递进搜寻法，这个算法不仅运行速度快，实现简单，而且具有较强的适应性。     

HGPX-WSY型液压仿形旋压成形机床的研制

介绍了HGPX—WSY型自动液压仿形缩脚机床的设计方案、技术特色、总体结构、液压、电器控制系统及应用实例。该机床采用PLC控制、全液压驱动，旋轮的运动轨迹由仿形模板决定，具有旋压成形及整形或切边多重功能，特别适用于各类筒形及杯形类零件的局部缩径成形。     

板材液压成形技术及其新进展

板材液压成形是一种先进的塑性加工技术,本文介绍该技术的发展概况,并对近年来新开发的成形新工艺,包括板材成对件液压成形、液压热成形和变压边力技术等,做了详细的介绍。     

液压柔性高精度冷拔机的成形力分析

针对冷拔管材的诸多优点，在介绍冷拔技术应用的基础上，根据对弹塑性静力、管材表面的变形、流体动力的润滑和拉拔力的深入研究，对高精度液压柔性冷拔的成形力进行分析，并对其成形原理作了一定的探讨。     

超高压管材液压成形控制系统的研制

介绍了管材液压成形工艺,根据液压成形原理,自主研制出具备高压发生器、阀门管路等配件的超高压液压系统,同时通过可编程控制器实现对电磁元件的控制,有效地解决了管材在液压成形过程中的端口密封、进给补料等关键问题,为管材液压成形的实验研究奠定了基础。     

加载路径对液压胀形管材成形性能的影响

在管材液压胀形过程中,加载路径对管材成形性能有着重要的影响,一直是研究热点。本文介绍了目前管材液压胀形中的各种加载路径如线性加载、折线加载、脉动加载和由模糊逻辑控制加载路径方式,阐述了各种加载路径的特点、原理及其对管材成形性能的影响,指出了深入研究加载路径要解决的几个关键问题。     

基于径压胀形确定管材的摩擦因数

摩擦对管材液压成形有极大的影响,管材摩擦因数的确定是一项极其重要的工作。在分析比较现有测试方法的基础上,基于径压胀形原理及其变形规律提出确定管材液压成形胀形区摩擦因数的新模型。该模型以恒定内压力下圆形管材径压胀形成方形断面后,以断面对角线长度差作为确定摩擦因数的测量指标。对比对角线长度差的有限元数值模拟结果及实测结果,以此确定管材液压成形时胀形区的摩擦因数。对低碳钢及不锈钢管的有限元数值模拟分析表明：对角线长度差与摩擦因数及内压力均成指数关系,该长度差对摩擦力很敏感且可方便测量,也可作为针对管材液压成形胀形区润滑剂特性的评定指标。所提出的新模型具有简单、实用等优点。     

Tube hydroforming compression test for friction estimation—numerical inverse method, application, and analysis

Friction plays an important role in forming processes, in fact it influences the material flow and therefore it affects the process and part characteristics. In particular, friction is a very influencing factor in tube hydroforming (THF), where high die–part contact pressure and area make the material sliding very difficult. As a consequence, the material hardly flows to the expansion zones and the part formability can be compromised. To obtain sound parts, FEM models allow the study of the process and optimize its parameters, but they require the right definition of the friction at tube–die interface. For these reasons, friction represents a key-point in THF processes and its knowledge and prediction are very important even if, nowadays, a comprehensive friction test for THF is not available in literature. With this paper, the authors want to propose and evaluate a method to estimate friction for THF processes. In particular, a numerical inverse method allowing the estimation of the Coulombian friction coefficient combining experimental test and FE simulation results will be described. The method is based on the effects of friction on the tube final thickness distribution when it is pressurized and compressed by two punches under different lubrication conditions without expansion. In particular, how the use of few and fast FE simulations allows to estimate an analytical function that takes into account the process conditions and that can be used in combination with experimental results in order to estimate the friction coefficient in THF processes will be shown.     

基于管端轴向位移驱动的T型管液压成形

管液压成形(THF)过程非常复杂,它往往要求管内压力施加和管端轴向位移准确配合以成形出高品质的零件,为此需要配有管端轴向进给控制系统和昂贵的超高压泵给系统。本文针对T类型管件,提出一种更简单的技术:管端轴向位移驱动式管液压成形技术。模拟和试验结果显示,这种方法加载路径容易选择且过程简单,因此可以有效简化THF设备,缩减生产成本。     

Design of T-shaped tube hydroforming using finite element and artificial neural network modeling

Journal of Mechanical Science and Technology - Tube hydroforming (THF) is a frequently used manufacturing method in the industry, especially on automotive and aircraft industries. Compared with...     

Evaluating the flow stress of aerospace alloys for tube hydroforming process by free expansion testing

In order to obtain accurate tube hydroforming (THF) simulation results, one of the important inputs in the finite element model (FEM) of the process is the mechanical response of the material during THF. Generally, the mechanical response is defined by the stress–strain behavior that can be determined from tensile testing of the specimens extracted either from the sheet used for roll forming of the tubes or directly from the tubes. More recently, free expansion testing has been used to characterize the mechanical response of the material for hydroforming applications. The free expansion test can emulate process conditions similar to those found during THF, and as such, can be used to obtain reliable and accurate information on the mechanical response/properties of the tubular material. The aim of this research is to present an approach for evaluating the stress–strain behavior of different materials using a 3D deformation measurement system in conjunction with an analytical model. Here, to characterize the mechanical response of the materials, free expansion and tensile testing were used for austenitic stainless steel types 321 (SS 321) and 304L (SS 304L), INCONEL® alloy 718 (IN 718), and aluminum alloy 6061 in the annealed “0” temper condition (AA 6061-0). The mechanical response of each material, measured through free expansion testing of tubular forms, was compared to the respective stress–strain behavior determined from the uniaxial tensile test using ASTM E8 geometry specimens extracted from the tubes. For each material studied in this work, the two flow stress behaviors were distinct, indicating that the test method can have a noticeable effect on the mechanical response. Finite element analysis (FEA) of the free expansion of each material was also utilized to simulate the THF process with the flow stress curves obtained experimentally; the predicted expansion and burst pressure results were close to the experimental data indicating that the approach developed and described in this work has merit for characterizing the mechanical response of aerospace alloys for hydroforming applications.     

Cytotoxicity of aggregated fullerene C60 particles on CHO and MDCK cells

The cytotoxicity of fullerene C60 particles on two mammalian cell lines, i.e. the Chinese hamster ovary (CHO) cells and the Madin-Darby canine kidney (MDCK) cells, has been investigated. Although innate fullerene particles have a very low solubility in deionized (DI) water, these particles can be dissolved in the tetrahydrofuran (THF) solvent at a great value. Further, the dissolved fullerene particles in the THF solvent could be extracted into a DI water solution at a significantly increased solubility. The formation of fullerene particle aggregates is believed to be the cause of the increased solubility. Results presented here show that once the concentration of the fullerene aggregates reaches a certain level, the cells start to die. The lethal dosage LD50, which is defined as the lowest fullerene concentration that results in a 50% cell death within 24 h, has been determined. Furthermore, the percentage of cell mortality increased with increasing fullerene concentration and incubation time yielding a negative effect on cell viability. These results, illustrated by atomic force microscopy (AFM), dynamic light scattering (DLS) and other microscopic techniques, will help to better understand the side effects of fullerene particles in mammalian cells.     

Effect of bright annealing on stainless steel 304 formability in tube hydroforming

Effects of bright annealing (BA) on enhancing formability of stainless steel 304 tube in a tube hydroforming (THF) process were studied. The tube material was the metastable austenitic stainless steel 304 with an initial thickness of 0.5 mm and an outer diameter of 31.8 mm. Both FEA and experimental results showed that THF process of the investigated part alone failed to achieve desired tube expansion of the diameter of 50.8 mm without severe fracture. Thus, a heat treatment process, also known as bright annealing (BA), which caused little to none oxide on the surface of annealed tube, was considered. Initially, effects of different annealing parameters such as temperature and holding time on the material formability were investigated using tensile tests. Stress–strain responses of various conditions were compared. As a result, an annealing process consisted of heating at the temperature of 1,050 °C, holding for 30 min, and rapidly cooling by purging N₂ gas was identified. This annealing should be applied intermediately after a pre-forming step. With the aid of the BA process, tube deformation was significantly increased and the required tube expansion could be therefore attained. In addition, strain-induced martensitic transformation occurred during the forming process was examined by X-ray diffraction (XRD) method. The amounts of martensite taking place in tubes (pre-forming, post-forming, and after annealing) were determined and discussed.     

GPC-十八角激光光散射联用法测定聚乳酸的分子量及分子量分布

介绍了一种用于可生物降解医用高分子材料聚乳酸（PLA）及其改性高分子的分子量和分子量分布测定的GPC-十八角激光光散射联用技术。给出了该方法的实验原理、实验步骤和方法，并对其分析测试过程中的关键实验技术及实验结果进行了详细的讨论。实验获得了满意的结果，该方法可作为常规测定聚乳酸（PLA）及其改性高分子分子量及其分布的测定方法。     

气相色谱-质谱法测定X胶囊的成分(英文)

建立了采用气相色谱-质谱法(GC/MS)确定X胶囊中内容物组成的方法。X胶囊中的内容物研磨成细粉后用乙醚提取,挥干乙醚后,溶于四氢呋喃进样。测定结果表明:样品溶液获得的GC/MS谱图数据与甾体化合物甲基睾丸素(甲睾)非常相似。通过对照发现样品的GC/MS谱图与甲睾标准品的GC/MS谱图完全相同。由此可以鉴定X胶囊样品为甲睾。