Flexible-die forming process with solid granule medium on sheet metal

Certain non-metallic granules （NMG） were selected as the research object. It was proposed to conduct the volume compression experiments as well as those on the NMG physical properties at high stress levels. Then, not only the volume compression ratio curve but also the extended Drucker-Prager linear model were obtained. In addition, through the friction strength tests, parameters of the Mohr-Coulomb model were gained, which proved in basic agreement with those of the extended Drucker-Prager linear model. Additionally, curves of the friction coefficients between the NMG and the sheet metal trader different pressures were also obtained. Based on the material performance experiments, numerical analysis in respect of flexible-die forming process with solid granule medium （SGM） was conducted. The die and device for experiments of solid granule medium forming （SGMF） on sheet metal were designed and manufactured. Typical parabolic parts were successfully trial-produced. The tests and simulation results show that the sheet formability is significantly improved for the extraordinary friction performance during interaction between the SGM and the sheet metal surface. The process control and die structure are simple, and the shaped work-pieces enjoy many advantages, such as satisfactory surface quality and favorable die fitability, which offers a brand-new method and means for processing and preparation of sheet metals.

Heat treatment and granule medium internal highpressure forming of AA6061 tube

The new forming process of AA6061 alloy tube, including solution treatment, granule medium internal high-pressure forming and aging treatment, was developed. The AA6061 alloy tube via heat treatment satisfied the forming requirement, and the granule medium internal high pressure forming method for AA6061 alloy tube was also realized by using convenient implementation with low requirement of equipment and flexible design of product. At a solution temperature of 560℃ and time of 120 min, the elongation of the AA6061 extruded tube increases by 300% and the strength and the hardness dramatically decrease too. Therefore, the AA6061 alloy tube meets the requirement of internal high-pressure forming because of the improvement of formability. The experiments shows that the strength and hardness of AA6061 alloy workpiece recover to that of the as-received alloy at an aging temperature of 180℃ and time of 360 min, and the strength of AA6061 alloy workpiece is equal to the base alloy. The typical parts of convex ring tube, stepped shaft tube and hexagonal tube were successfully produced in lab by using the present forming method. The forming tests show that the maximum expansion ratio(MER) of the AA6061 extruded tube increases by 25.5% and the material properties of formed AA6061 alloy tube reached the performance of as-received alloy.

Hot Granules Medium Pressure Forming Process of AA7075 Conical Parts

High strength aluminum alloy plate has a low elongation at room temperature, which leads to the forming of its components need a high temperature. Liquid or gas is used as the pressure-transfer medium in the existing flexible mould forming process, the heat resistance of the medium and pressurizing device makes the application of aluminum alloy plate thermoforming restricted. To solve this problem, the existing medium is replaced by the heat-resisting solid granules and the general pressure equipments are applied. Based on the pressure-transfer performance test of the solid granules medium, the feasibility that the assumption of the extended Drucker-Prager linear model can be used in the finite element analysis is proved. The constitutive equation, the yield function and the theoretical forming limit diagram（FLD） of AA7075 sheet are established. Through the finite element numerical simulation of hot granules medium pressure forming（HGMF） process, not only the influence laws of the process parameters, such as forming temperature, the blank-holder gap and the diameter of the slab, on sheet metal forming performance are discussed, but also the broken area of the forming process is analyzed and predicted, which are coincided with the technological test. The conical part whose half cone angle is 15° and relative height H/d0 is 0.57, is formed in one process at 250℃. The HGMF process solves the problems of loading and seal in the existing flexible mould forming process and provides a novel technology for thermoforming of light alloy plate, such as magnesium alloy, aluminium alloy and titanium alloy.

Stress-strain analysis on AA7075 cylindrical parts during hot granule medium pressure forming

Hot granule medium pressure forming(HGMF) is a technology in which heat-resistant granules are used to replace liquids or gases in existing flexible-die forming technology as pressure-transfer medium. Considering the characteristic of granule medium that seals and loads easily, the technology provides a new method to realize the hot deep-drawing forming on high strength aluminum alloy sheet. Based on the pressure-transfer performance test of granule medium and the material performance test of AA7075-T6 sheet, plastic mechanics analysis is conducted for the areas, such as the flange area, force-transfer area and free deforming area, of cylindrical parts deep-drawn by HGMF technology, and the function relation of forming pressure is obtained under the condition of nonuniform distribution of internal pressure. The comparison between theoretical result and experimental data shows that larger deviation occurs in the middle and later period of forming process, and the maximum theoretical forming force is less than the experimental value by 24.6%. The variation tendency of the theoretical thickness curve is close to the practical situation, and the theoretical value basically agrees well with experimental value in the flange area and the top area of spherical cap which is in the free deforming area.

Research on Extrude-bulge Forming of Tee Tubes with Plastic Medium

This paper presents an experimental research on extrude-bulge forming of tee tubes with plastic medium,an universal device especially designed for this forming process and some parameters having effects on the forming process.Comparison of results of the theoretical analysis with experimental results shows a very good agreement between them.

Process of back pressure deep drawing with solid granule medium on sheet metal

The experimental die apparatus of the solid granules medium forming on sheet metal was designed and manufactured.Typical parts,such as conical,parabolic,cylindrical and square-box-shaped components,were successfully trial-produced as well.According to the analysis of the changing trends of the cross-section shape and the wall thickness during the process,it can be found that the shape of the free deformation zone of the sheet metal,which is the most critical thinning area,can be described as an approximately spherical cap.According to this forming feature,back pressure deep drawing technology with solid granules medium on sheet metal was proposed to restrain drastic thinning at the bottom of the part through the joint friction effect of solid granules medium,the back pressure tringle and the sheet metal.Therefore,the deep drawing limit of the sheet metal is significantly improved.In order to fabricate thin-walled rotary parts with great drawing ratio and complex cross-sections,a finite element model based on the material property test of the solid granules medium was established to optimize the scheme of the back pressure deep drawing.The effects on the forming performance of sheet metal from back pressure load and the approach of blank holding control were analyzed through this model.

Fundamentals and Processes of Fluid Pressure Forming Technology for Complex Thin-Walled Components

A new generation of fluid pressure forming technology has been developed for the three typical structures of tubes,sheets,and shells,and hard-to-deform material components that are urgently needed for aerospace,aircraft,automobile,and high-speed train industries.in this paper,an over all review is introduced on the state of the art in fundamentals and processes for lower-pressure hydroforming of tubular components,double-sided pressure hydroforming of sheet components,die-less hydroforming of ellipsoidai shells,and dual hardening hot medium forming af hard-to-deform materiais Particular attention is paid to deformation behavior,stress state adjustment,defect prevention,and typical applications.In addition,future development directions of fluid pressure forming technology are discussed,including hyper lower-loading forming for ultra-large non-uniform components,precision for ming for intermetallic compound and high-entropy alloy components,intelligent process and equipment,and precise finite element simulation of inhomogeneous and strong anisotropic thin shells.

Viscous Inner and Outer Pressure Forming Method of Thin-walled Tube and Its Application

Aiming at overcoming the difficulties in integral forming of thin-walled tubes with complex shapes, a novel forming method by inner and outer pressure through viscous was proposed. In this method, by dividing large deformation of the part into inner and outer pressure forming deformations, the limit deformation of tube part can be increased by several times. Meanwhile, the principle of viscous inner and outer pressure forming was provided, and key problems during the forming process such as reduction of the wall-thickness and instability wrinkling were analyzed. Thereby, the complex curved surface super-alloy GH3044 thin-walled tube with varying diameter ratio of 1.35（the ratio between the maximum and minimum diameters of the part） can be integrally formed by this method. The experimental surface of the formed part is superior in quality and the wall-thickness distribution is uniform. The results show that the viscous inner and outer pressure forming can provide a new approach for integral forming of thin-walled tubes with complex shapes.

Finite element analysis and experiment research on aluminum alloy ladder bowl with viscous pressure forming (VPF)

The process parameters of aluminum alloy ladder bowl with viscous pressure forming and solid metal punch forming were numerically simulated by commercial finite element software DEFORM. The influence of blank holder pressure (BHP) on the formability of sheet metal was investigated. It was found that lower BHP does benefit to the distribution of thickness both with VPF and with solid punch forming. The forming force needed in VPF is bigger than that of with solid punch forming at the same stroke. The distribution of thickness with VPF is more uniform than that of with solid punch forming. Compared with solid punch forming, the damage values of workpiece at the top convex corner are lower by VPF. It was also shown that fracture tendency could be reduced with VPF, so that means the formability is improved. At the same time, aluminum alloy ladder bowl was manufactured with VPF. The results show that the simulation results are in agreement with the experimental data very well.

Inner and outer pressure forming of nickel based super-alloy thin-walled part with variable diameter sections

A novel forming method of nickel based super-alloy thin-walled part with variable diameter sections was proposed by using inner and outer pressure with the visco-elasto-plastic pressure-carrying medium at room temperature,and the principle of the method was provided.Experiments and FE simulations were carried out to analyze the deformation characteristics for the part with larger variable diameter ratio(35%).The results show that visco-elasto-plastic pressure-carrying medium can meet the requirements of the room-temperature deformation condition for nickel based super-alloy sheet.The inner and outer pressure forming with the visco-elasto-plastic pressure-carrying medium can meet the requirements of dimensional accuracy for the thin-walled part with variable diameter sections.The thinning of wall-thickness is less than 4%.This method provides a new approach for near-net shape forming of nickel based super-alloy thin-walled parts with variable diameter sections.

新零售业态下中小型网店运营策略

新零售背景下,当下网店运营与服务模式均迎来了新的转变,各种企业的信息更加透明化,通过对无形资源价值动态的把握来创造更多的有形、无形资源的抓取。另外新零售模式也使得以前对于不对称、信息差认知的可能逐步降低。新零售模式下整体的行业信息透明化、对策化幅度逐渐升高,从以前的单纯成交的关系逐步转化成现在以客户关系为中心的管理模式。当下针对零售企业提高创新服务模式,做好创新服务模式的绩效,以服务创新驱动力模型将内部和外部因素进行总体把握问题,从经济价值,功能价值,情感价值三方面充分考虑到顾客的主张,希望通过理论综述结合案例分析对于新零售背景下的服务模式以及营销方式背后的作用机理开展进一步的研究,以期对于理论和实践具有一定的指导价值。

Distribution and exploration direction of medium-and large-sized marine carbonate gas fields in Sichuan Basin, SW China

Based on the analysis of the basic characteristics of medium-and large-sized marine gas fields in Sichuan Basin, combined with the division of major reservoir forming geological units in the marine craton stage and their control on key hydrocarbon accumulation factors, the distribution law of medium-and large-sized marine carbonate gas fields in the basin was examined and the exploration direction was pointed out. Through the analysis of the periodic stretching-uplifting background, it is concluded that five large scale paleo-rifts, three large scale paleo-uplifts, five large scale paleo erosion surfaces were formed in the marine craton stage of Sichuan Basin, and these geological units control the key reservoir forming factors of medium and large sized gas fields:(1) Large-scale paleo-rifts control the distribution of high-quality hydrocarbon generation centers.(2) The margin of large-scale paleo-rifts, high position of paleo-uplifts and paleo erosion surfaces control the distribution of high-quality reservoirs.(3) Large-scale paleo-rifts, paleo-uplifts, paleo erosion surfaces and present tectonic setting jointly control the formation of many types of large and medium-sized traps.(4) Natural gas accumulation is controlled by the inheritance evolution of traps in large geological units. Based on the comparative analysis of the distribution characteristics of medium-and large-sized gas fields and large geological units, it is proposed that the superimposition relationship between single or multiple geological units and the present structure controls the distribution of medium-and large-sized gas fields, and the "three paleo" superimposed area is the most advantageous. According to the above rules, the main exploration fields and directions of medium-and large-sized marine carbonate gas fields in Sichuan Basin include periphery of Deyang-Anyue paleo-rift, eastern margin of Longmenshan paleo-rift, margins of Kaijiang-Liangping oceanic trough and Chengkou-western Hubei oceanic trough, the high part of the subaqueous paleo-uplifts around Central Sichuan, paleo erosion surfaces of the top boundary of Maokou Formation in eastern and southern Sichuan Basin, paleo erosion surfaces of the top boundary of the Leikoupo Formation in central and western Sichuan Basin.

既有中小型酒店更新改造设计研究——以济南东源大厦为例

随着经济增长与社会发展,城市更新的需求不断加强,既有酒店建筑作为城市的重要构成,其更新改造随之提上日程。酒店建筑的改造涉及的学科范围广泛,门类众多,其改造设计策略仍待于实践中持续探索。文章选择了济南市东源大厦改造更新的实践案例,从院落环境升级,外部形态更新,内部功能改造等方面分析,对现有中小型酒店建筑更新改造的设计方法进行探索,提出场地景观重新规划、对立面入口更新、优化交通流线、公共空间重组、房型升级的具体改造方法,使其融入城市环境,满足使用需求,为更多此类工程提供一个思路与借鉴。

AZ31镁合金板材准静态-动态冲击流体介质温热复合成形极限研究

基于Nakazima半球凸模胀形试验,对AZ31镁合金板材进行了成形极限试验,探究了AZ31镁合金板材在准静态-动态冲击流体温热复合成形下成形极限分布规律。结果表明,温度升高会提升AZ31镁合金板材的极限应变,对比准静态与复合成形两种方式下的极限应变发现, AZ31镁合金板材在准静态-动态复合成形下极限应变值更高,塑性成形性能得到改善。对两种成形方式下的断口形貌扫描进行分析,结果表明,准静态-动态复合成形的韧窝比准静态成形的韧窝多且深。对不同成形方式试样在室温、 100及200℃下进行了EBSD分析,发现在室温时,复合成形出现了少量{10-12}拉伸孪晶协调变形。在100℃时,复合成形引入细而薄的拉伸孪晶片层,切割细化晶粒,塑性较准静态成形得到提升。200℃下比准静态成形产生更多的再结晶晶粒是复合成形塑性提高的主要原因。

切顶成巷技术在煤矿开采中的价值分析

本研究针对黑龙江鸡西矿业集团有限责任公司下属煤矿面临的采掘接替紧张与回采率低下两大难题,运用价值工程的七个逻辑程序,进行了深入分析与解决方案设计。通过现场勘探与数据整理,本研究确认切顶自成巷技术为有效解决方案,该技术旨在优化采掘布局,提升安全性和经济效益。在严格遵循价值工程逻辑程序的基础上,提出了包含“切、补、护、支”四个环节的改进方案,并通过矿压监测确保技术功能满足实际需求。经过成本与价值分析,确定该方案具有显著的经济效益和安全效益。据预测,实施切顶自成巷技术后,矿井将实现采掘接替的有效缓解,回采率显著提升,并有望为矿井带来约6761万元的额外收益。研究不仅为鸡西矿业集团解决了实际问题,也为类似条件的煤矿提供了可行的技术路径与参考。未来,将继续关注技术应用效果,不断优化完善,推动矿业安全与效益的双提升。

柱形装药土介质爆炸成坑效应的数值模拟研究

本文指出在爆炸案件中,为便于携带、掩人耳目,犯罪分子采用的炸药包装物常为瓶、罐等柱形物体;土体是爆炸现场的常见介质,土介质爆炸成坑效应的研究对爆炸案的现场重建等技术工作具有重要意义。为了研究柱形装药土介质爆炸成坑效应,通过量纲分析得出了一定条件下炸坑比例直径、炸坑比例深度是柱体比例半径和比例埋深的二元函数,并通过LS-DYNA模拟了不同柱体比例半径、比例埋深的爆炸成坑过程,根据模拟实验数据拟合出了该函数关系,最终得到了爆炸抛掷作用直径、炸坑真实深度与装药半径、炸药埋深之间的关系。

板料固体颗粒介质成形新工艺及其数值模拟

在板料成形技术中,板料软模成形是板料成形工艺中发展最快的工艺。但传统的板料软模成形工艺存在着许多缺点。为此,提出了既能克服现有软模成形工艺的缺点,又汲取各自优点的新的软模成形工艺——板料固体颗粒介质成形新工艺。板料固体颗粒介质成形新工艺是采用固体颗粒介质代替刚性凸模(或弹性体、液体)的作用对板料进行软模成形的先进工艺。该工艺具有模具结构简单,零件表面质量好,能够有效提高板材成形极限,节省多套模具和设备等优点。应用本工艺成功试制出深曲面类典型零件。通过将固体颗粒介质作为连续体介质处理,建立了子午面为抛物线形件的有限元模型。模拟和实测结果对比表明,应用连续体材料模型的模拟结果和实测结果较为接近。

管材固体颗粒介质成形工艺及其塑性理论研究

提出一种既能克服刚性模成形和软模成形的缺点又吸取它们各自优点的成形工艺———管材固体颗粒成形工艺(SGMF),为材料的制备和加工提供了新的方法和手段。采用塑性理论对非均匀内压作用下的管材成形过程中的自由变形区塑性变形进行研究,建立了在非均匀内压作用下的管材成形塑性理论,得到了自由变形区的应力、应变及其壁厚的理论计算公式,并通过试验进行了实际验证。

管材固体颗粒介质成形新工艺

传统的软模成形技术促进了管材成形技术的发展,但也存在许多不足。针对传统软模成形的缺点提出管材固体颗粒介质成形新工艺(Solid granules medium forming technology,SGMF)。该新工艺既可解决流体介质、粘性介质的密封难题,又具有内压非均匀分布,便于控制工件成形,提高材料成形极限的优点,为材料的制备和加工提供了新的方法和手段。针对固体颗粒介质传压特点,提出线性载荷模型和余弦载荷模型。采用塑性理论对非均匀内压作用下的管材成形过程中,自由变形区塑性变形进行研究,建立在非均匀内压作用下的管材成形塑性理论,得到自由变形区应力、应变、厚度计算公式,并通过试验进行实际验证。

镁合金板材的固体颗粒介质拉深工艺参数

提出基于固体颗粒介质成形(SGMF)工艺的镁合金板材差温拉深工艺,并展开试验研究。通过对AZ31B镁合金薄板进行差温拉深成形试验,研究了成形温度、拉深速度、压边力、压边间隙、凹模圆角和润滑条件对拉深性能的影响,确定AZ31B镁合金板料最佳成形工艺参数。结果表明:该工艺可显著提高镁合金板材的成形性能,成形温度及拉深速度对板料拉深性能影响较大,板料最佳成形温度区间为290～310℃,颗粒介质与板料理想温差为110～150℃;压边力和压边间隙对拉深性能产生联合影响;此外,凹模圆角和润滑条件也对拉深性能有一定的影响。当上述工艺参数达到最佳值时成功拉深出极限拉深比(LDR)为2.41的工件。