Computer methods of structural analysis

Amorphous metallic brazing alloys are used widely for brazing dissimilar materials, including corrosion-resisting steels. The results of detailed tests carried out in accordance with the GOST standard in tensile, impact, and bend loading are presented, and the results of non-standard torsion tests of brazed joints are also outlined.     

Weathering structural steels corrosion in atmospheres of various degrees of pollution in Romania

The atmospheric corrosion behaviour of CORTEN weathering steel grade in various atmospheric environments in Romania is presented. The researches were accomplished on two types of weathering structural steels exposed 20 years in urban‐industrial and rural environments (characterised according to ISO 8565 and ISO 9223 as corrosivity classes C5 and C1). The experimental results emphasise that corrosion rate stabilised at 0.08–0.10 mm/year after about 10 exposure years, and electronic microscope examination showed that corrosion products layer enriches in alloying elements (Cr, Ni, P, Cu) and in stable crystalline products like Fe₂O₃ and α‐FeOOH that passivate steel. Passive layer compactness, studied by its moistening capacity, increases with time. Corrosion products layer composition and elements distribution was studied using an electronic microprobe; crystalline phases composition was determined by X‐ray diffraction.     

液压缸结构分析的网格自动生成

针对典型液压缸截面特征，给出一种简明的三角形单元网格生成算法。它作为液压缸CAD系统有限元分析前置处理的数学模型之一，可有效提高分析效率。     

连杆冲压工艺分析及结构设计

针对连杆进行冲压工艺分析,通过比较两套级进模排样方案,最终设计了双侧载体、双侧导正钉导正的排样方案。排样依次安排冲裁、弯曲、空工位、切断等10个冲压工序,材料利用率达到43.3%。考虑到模具精度、模具强度、加工方法等因素,对工作零件和辅助零件等部件的模具结构进行设计。针对小直径冲裁凸模容易磨损、需更换的特点,设计了快换式凸模,且凸模工作部分添加保护套,异形冲裁凸模采用挂台定位。凹模采用镶块结构,由台肩式或过盈配合方式固定。向下弯曲模具预留避让槽,向上弯曲凸模安装在卸料板上,保证弯曲顺利进行。设计了由矩形截面弹簧、弹性管、螺杆和螺塞组成的弹性卸料装置,节省弹簧运行空间。本文设计的连杆级进模设计方案能够满足工业生产要求。     

检具底座变形分析与结构优化

基于CAE技术对某汽车检具底座的承载能力进行了分析,获得底座结构的最大变形量,并基于分析结果对底座各部分的承载能力进行了评估,对检具底座结构进行了减重优化设计。研究结果为检具底座结构的拓扑优化提供了相关依据,节约了产品材料,降低了研发成本。     

顶盖流动方案对比分析

以顶盖注射过程中多种流动方案分析为例介绍了MPI的作用,通过应用MPI6.1软件对2种CAE流动方案进行填充对比分析,得到了多种切实可行的方案,充分展现了CAE技术在浇注系统设计和注射模开发过程中所起到的重要作用。     

Interactive analysis of the structural mechanic behaviour of machine tools

The simulation method described in this technical paper has been developed within the AiF ZUTECH Project 95 ZN funded by the Bundesministerium für Wirtschaft und Technologie. Goal of the project was the development of an interactive analysis of the position dependent behaviour of a machine tool within the whole workspace based on finite element simulation results on a conventional PC or by means of the virtual reality.     

基于结构应力的焊接接头疲劳分析

基于结构应力法对来自相关文献中的16Mn钢十字非承载焊接接头、十字承载接头和纵向立板角焊缝接头的疲劳强度的试验数据进行了分析.推导了适合有限元计算的离散结构应力计算公式,得到焊接接头的结构应力集中系数.证实了该方法具有网格划分不敏感性,给出了应用结构应力法进行疲劳评定时适合上述各类接头的结构应力S-N曲线.结果表明,同名义应力法相比较,采用结构应力表示的焊接接头疲劳试验数据其分散性较小.     

Fine domain structural analysis of donor-doped BaTiO3 by CBED

Since electrical properties of ferroelectric materials strongly depend on domain morphologies. the structural relationship between two domains is important in understanding the domain wall function. Fine domain structures are found along grain boundaries in lightly donor-doped BaTiO₃. For the structural analysis of theses areas, the high spatial resolution of the CBED technique is required. This paper describes, the CBED technique to analyze the structural relationships between adjacent domains. This procedure con give the more detailed structural information about polarization alignment, thereby the increasing understanding of the PTCR phenomenon of donor-donor doped BaTiO₃ materials.     

十字型万向接轴强度分析及结构优化

介绍了用有限元分析十字轴式万向接轴的建模方法和分析思路 ,讨论了十字轴、轴承座及叉形座的应力分布、接轴的结构设计、轴承座预紧力等问题     

Phase and structural transformations in the aluminum amts alloy upon severe plastic deformation using various techniques

The paper presents experimental data on the structure formation in the commercial aluminum alloy of grade AMts subjected to severe plastic deformation using dynamic channel-angular pressing and torsion under high quasi-hydrodynamic pressure in Bridgman anvils. The dependences of the structural characteristics and hardness on the degree, rate, and scheme of deformation have been analyzed.     

Effects of various metal seed layers on the surface morphology and structural composition of the electroplated copper layer

This study examined the effects of depositing a seed layer on the surface morphology and the electric characteristics of an electrodeposited copper foil. Pt, Pd, a Pt-17Pd alloy and gold were used as the seed metals. The morphology, crystal structure, and electric characteristics of the electrodeposited copper foil were examined by scanning electron microscopy, X-ray diffraction, atomic force microscopy, and a four-point probe, respectively. The surface roughness, crystal growth orientation, and resistivity were controlled using various seed layers. Large particles were observed on the surface of the copper layer electroplated onto the Pd seed layer. However, a uniform surface was obtained when a Pt seed layer was used.     

Vibration analysis and cutting simulation of structural nonlinearity for machine tool

The dynamic behavior of a machine tool is affected by the forces applied to the structure. However, cutting processes have been analyzed considering the linear systems in most of the studies so far. In this study, a machine tool structure was excited by using an electromagnetic shaker and the force-dependant frequency response characteristics were measured. Based on the measured result, the nonlinear characteristics of the machine tool structure was identified, and a machine tool with the nonlinear characteristics was mathematically reproduced, which enabled to analyse the nonlinear frequency response characteristics and simulate cutting processes.     

The production of large structural titanium castings

Titanium-alloy castings have recently become an attractive option for critical-structural applications in aerospace structures. These opportunities have occurred primarily because of the development of advanced-process technologies, such as rapid-prototyping methodology and solidification modeling, which have dramatically reduced the cost and time required to obtain first-article castings through concurrent engineering. Moreover, these technologies have lowered the risk involved in examining new applications for titanium castings. This article examines the implementation of these new technologies and the heat treatment and mechanical properties of large structural castings, particularly in relation to section size. Additionally, the production of a cast-titanium transmission adapter for the V-22 Osprey Tiltrotoraircraft is described. Editor’s Note: Although JOM typically employs metric units only, this article features U.S. customary units as a reflection of the industry standards described. J. Klepeisz earned his B.S. in metallurgical engineering at the University of Illinois in 1984. He is currently plant manager of structural business operations at Howmet Hampton Casting. S. Veeck earned his B.S. in metallurgical engineering at the University of Illinois in 1963. He is currently senior staff engineer at Howmet Research Corporation.