有效降低折弯机喉口处应力的机身优化设计

喉口是折弯机机身结构中的薄弱环节,该处应力集中比较严重。本文结合MB8-250×3200数控折弯机新机型研发项目,采用有限元法对机身进行了优化。优化后的机身不但有效地降低了喉口处的应力,而且节约了材料,提高了经济效益。     

折弯机参数化建模及优化

本文采用参数化建模方法建立折弯机的实体模型,并建立滑块与工作台之间的接触对有限元模型,对其进行静态分析;在参数化模型基础上进行优化设计,以喉口及油缸连接处应力为约束条件,最终通过优化获得折弯机的质量最轻.     

基于ANSYS Workbench的数控折弯机的优化设计

文章利用有限元方法,借助Ansys workbench 14.0,以减重为优化目标,在保证结构具有足够强度和刚度的基础上,对原有某折弯机结构分别进行了尺寸优化和拓扑优化,给出了结构的优化模型。同时,对结构中不满足强度和刚度要求的部位进行了改进。尺寸优化后,滑块的最大位移降低19%,最大等效应力降低44%;机架的危险部位最大等效应力降低56%,机架的质量降低了12.7%。拓扑优化后,机架的质量减轻了19.1%。折弯机的综合性能得到大幅提升。     

基于有限元技术的折弯机滑块分析与改进设计

滑块是数控板料折弯机的重要组成部分,对加工工件的精度有着重要影响。本文采用ANSYS有限元分析软件建立了折弯机整体有限元模型,对折弯机滑块进行了静力学分析,研究了滑块的应力分布与变形情况,研究发现液压缸活塞杆与滑块安装的方形开口周围应力过大。为提高该处结构强度,提出几种改进设计方案,通过有限元计算结果的比较,最终确定最合理的设计方案。     

利用振动时效控制吊钩侧板变形的实验研究

吊钩侧板销孔处焊接凸台在提高吊钩承载能力的同时常常引起侧板变形,严重影响了吊钩的装配。本文介绍了利用振动时效的方法来降低焊接残余应力和控制吊钩侧板的焊接变形。首先从应力应变机制和位错移动两个方面进行理论分析,然后进行了振动时效的实验研究。实验结果表明:相对于未处理的吊钩侧板件,振动时效处理后的侧板件变形量降低了66.9%,达到了侧板的装配要求,同时使用超声波探伤仪检测侧板焊缝,且没有引入内部缺陷。     

基于COSMOSWorks的某冲压液压机机身优化设计

对某型号液压机进行了优化设计.通过对机身喉口形状改进,添加加强筋板,完成了机身的优化.机身的应力降低了一个数量级,安全系数增大了一个数量级.经过此优化设计,将避免因机身的安全系数过大而浪费材料.     

基于ANSYS Workbench的龙门式折弯机机架模态分析及工作台拓扑优化

为研究龙门式折弯机的静力学性能及其在满载工作时机架的抗振性能,运用ANSYS Workbench对一款龙门式折弯机机架进行有预应力的模态分析,得到静力学分析结果和前6阶固有频率及对应振型。利用拓扑优化,对折弯机工作台进行去除材料的形状优化,根据拓扑优化云图修整形状尺寸,然后在Solid Works中对工作台模型进行重建,将优化后的模型再次导入ANSYS Workbench中进行预应力模态分析,对优化前、后机架的静力学性能和动态特性进行比较和分析。最终,优化后的工作台质量减轻了11.7%,最大等效应力也有所减小,并且,龙门式折弯机的抗振性能不会受到影响,确定了拓扑优化的可行性。     

折弯机滑块变形分析及实验测试

折弯机在折弯载荷作用下的变形直接影响折弯机的刚性,从而决定折弯机的折弯精度,而折弯载荷的确定是其中的关键问题。以某型数控折弯机为研究对象,采用Solid Works建立三维模型,利用DEFORM-3D有限元分析软件对折弯过程进行仿真,计算表明滑块在主要承受竖直方向折弯力的同时,还受到板料对滑块的水平推力。将仿真计算得到的折弯力施加到折弯机的有限元模型,获得了折弯机的整体变形规律。为了验证折弯机有限元计算结果的正确性,对折弯机滑块的变形进行了实验测试,试验测试值与有限元计算值比较接近,为进一步完善和优化折弯机结构提供了理论依据。     

折弯机机架变形应力的有限元分析

采用ANSYS有限元软件对折弯机机架进行的三维变形应力分析,找出了其薄弱环节;并对机架变形进行实际测试,经比较有限元分析与测试结果吻合良好。为折弯机的结构优化设计提供了有价值的探索。     

折弯机三大件多层分体结构设计研究

立柱、工作台和滑块是折弯机关键零件,其强度和刚性对机床精度影响至关重要。通过分析立柱、工作台和滑块的结构及受力状况,提出一种多层分体组合结构,代替整体焊接结构,降低单件外形和重量,达到便于加工、运输和安装的效果。通过实际使用验证得出多层分体结构是折弯机尤其是大吨位折弯机大件理想的结构方式。     

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.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.     

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。     

A STUDY OF TEMPERATURE-DEPENDENT VALENCE BOND STRUCTURE OF TITANIUM

On the basis of energy and shape method for the determination of the valence bond (VB) structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is e_c~(2.9907) · (s_c~(0.4980) d_c~(2.4927)) ef1.0093 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.