热带粗轧机组立过程的三维有限元模拟

本文采用全三维刚塑性有限元法对室温下的铝和不同温度下的２Ｓ－Ａｌ平辊侧压稳定变形过程进行了解析，计算结果和实测值吻合较好，较明显地提高了计算精度，并提出了用超薄单元近似处理奇异点的办法，使计算编程简化，能迅速地得到了较好的解。     

蠕变断裂局部损伤方法的有限元模型

提出了蠕变断裂局部损伤方法的有限元模型，通过有局部薄弱环到引入损伤单元，较好地不了多向应力条件下蠕变损伤发生和发展的规律，应用一有限元模型分析缺口圆棒试样的蠕变变形与损伤，得到的计算结果与试验结果能够较好的相吻合。     

超声速总压管气动特性的数值研究

建立了一种总压管的计算模型，0度攻角时，在马赫为1．1-2．4的超声速均匀来流条件下，计算值与理论值吻合得很好。在此基础上，模拟了两支总压管的角度特性，研究了来流马赫数及头部形状的影响，计算结果也与已有实验值吻合得较好。超声速来流条件下，该计算模型能够很好地捕捉总压管前的激波，刻画激波的强间断特性。     

太阳能溴化锂吸收式制冷装置工作过程模拟

以太阳能驱动溴化锂吸收式制冷实验装置为对象，应用MCGS组态软件建立了实验装置的工艺流程，建立了太阳能驱动溴化锂吸收式制冷装置仿真计算模型，应用VB编制了仿真计算程序。通过OLE自动化技术将VB和MCGS连接，把在VB中计算的运转参数和热工性能指标传送给MCGS用户界面，在MCGS工程中实时地显示溴化锂吸收式制冷热泵装置的工作参数和性能指标。在装置实验条件下得到较好的仿真结果。     

高速方尾水面舰船兴波问题计算方法研究

将Dawson型兴波阻力计算方法推广应用高速方尾水面舰船兴波问题计算，在计算中同时计入了尾封板0静压力，尾倾与下沉着因素的影响，以两高速方尾水面舰船为例计算了兴波问题，将兴波阻力计算值与剩余阻力模型试验值进行了比较，求出了相应的相关系数。结果表明，本方法可较好地求解高速方尾水面舰船的兴波问题，兴波阻力相关系数可用于修正理论计算结果，以提高计算精度。     

混凝土剪力墙荷载—位移全曲线非线性有限元分析的探讨

本文采用全量式本构模型，编制了包括上升段和下降段在内的荷载－位移全曲线的非线性有限元分析计算程序，较好地解决了下降段问题，计算和试验结果吻合较好。在有限元一理论中，考虑了混凝开裂后的软化效应和残余支持 力的影响。     

舰艇武器布置问题的一种协同优化算法

针对舰艇武器布置问题的特点，提出了一种基于粒子群优化和分类器系统的协同优化算法，以粒子群优化进行优化计算，用分类器系统消除约束．计算实例表明，该算法能较好地实现优化计算，并能节省大量的计算时间．     

循环载荷作用下钢纤维混凝土的损伤及演化行为的定量描述

基于对轴向循环压缩载荷作用下钢纤维混凝土损伤行为的试验研究，给出了一种适宜工程应用的钢纤维混凝土损伤程度的定量计算方法，并导出了描述其损伤演化的力学模型。与实验结果的对比表明，理论损伤演化模型较好地反映了实测钢纤维混凝土的损伤演化行为。     

大型舰艇系统破损失效概率计算

对于大型舰船，多次命中和结构防护成为破损失效概率计算的主要问题，该文通过对各种算法的比较和研究，综合了逻辑代数法、网格积分法和蒙特卡罗随机模拟法的优点，较好地解决了这些问题，得到了满意的计算结果。     

高层隔震模型结构双向地震反应的数值计算与试验

为研究高层建筑采用铅芯橡胶垫进行隔震后的结构减震效果,对一两向不同高宽比1:16小比例尺隔震结构模型,进行了双向不同地震波输入下的地震反应数值计算和振动台试验分析。对模型上部结构加速度和隔震支座位移反应的分析表明,隔震技术对高层建筑同样有较好的减震效果;数值计算结果与振动台试验结果的对比分析表明,两者具有较好的一致性,数值计算较好地模拟了振动台试验;两组数据的相近证明了数值计算结果和振动台试验过程进行的正确性。     

Proposal of bond criterion for hot roll bonding and its application

The aim of this work was to develop a bond criterion for laminated composites prepared by hot rolling. 7075 Al/AZ31B Mg/7075 Al laminated composites were fabricated by hot rolling at different reduction ratios and temperatures, and the hot rolling process was also simulated by finite element methods (FEM). The FEM results show that two stages existed for an option position of the interface during hot rolling, viz. the bonded interface forming period and the post-bonded period. Bonded interface would be damaged during the latter due to second tensile stress and tear stress (due to the sticking friction between the Al plates and the rollers during the rolling). A bond criterion for laminated composites fabricated by hot rolling was proposed, which includes a strain threshold and a critical bonding strength. The predicted bond results of the 7075 Al/AZ31B Mg/7075 Al laminated composite fabricated by hot rolling from the proposed bond criterion agreed with the experimental data.     

Surface plastic deformation distribution and microstructural evolution in the compound rolling of Ti–50Al billet

Compound rolling, which uses two different roller profiles to create plastic strain variation in the surface of a material, is described in this study. Based on the local load theory, equipment for the plastic deformation on the surface of the rectangular billet has been produced. The compound rolling behavior of Ti–50Al billet has been studied using this equipment. In order to study the deformation distribution of compound rolling, the flow net method for strain measurement has been employed. The deformation differences between compound rolling and flat rolling have been investigated with the commercial finite element method (FEM) code DEFORM-3D. The microstructure and the hardness from the surface to the center of the Ti–50Al billet developed through compound rolling has been characterized. These results indicate that the compound rolling technique results in severe plastic deformation near the surface with limited strain towards the center of the billet. This can result in compound microstructures, with fine recrystallized grains in the near surface region and the original directionally solidified microstructures in the center, and improve the hardness on the surface of the billet significantly.     

层状镁/铝复合板轧制工艺研究进展

镁/铝复合板具有密度小、比强度高和耐腐蚀性好等优点,广泛应用于航空航天、汽车制造等领域.轧制法是目前生产镁/铝复合板最为广泛的一种方法,该法设备简单、操作容易、成本低廉.介绍了普通轧制法、异步轧制法、爆炸+轧制法、累积叠轧法、固-液铸轧法、波-平轧制法6种轧制工艺,以及这些工艺在制备镁/铝复合板时的优缺点.波-平轧制工艺可以提高复合板的平直度,有利于板材后续加工成形.也研究了轧制温度、轧制压下率、轧制速度、轧后退火处理对镁/铝复合板力学性能的影响,镁/铝界面金属间化合物的形成因素,以及化合物层厚度对镁/铝复合板力学性能的影响.     

Evolution of strain states and textures during roll-cladding in STS/Al/STS sheets

The evolution of strain states and textures during roll-cladding of three plies of sheets comprising ferritic stainless steel (STS), aluminum (Al) and ferritic stainless steel was investigated by measurements of crystallographic textures and by simulations with the finite element method (FEM). Because the deformation mainly occurs in the Al layer during roll-cladding, the present investigation was focused on the Al layer located at the middle of clad samples. Roll-cladding of STS/Al/STS sheets led to the development of a strong through thickness texture gradient in the Al sheet which was characterized by shear textures at the surface layer and rolling textures at the center layer. The temperature of the cladding operation played an important role in the evolution of textures.     

铜／铝冷轧复合板剥离性能及界面摩擦分析

采用同步轧制方法制备铜／铝复合板,研究了轧制变形量对于铜／铝复合板结合强度和剥离表面形貌的影响,分析了轧制复合界面摩擦机理。研究结果表明,复合板结合强度、剥离表面粘铝、铜基体表面裂纹数都随着轧制变形量的增大而增大。变形量为50％时,结合强度为2N／mm,变形量为60％时,结合强度为7N／mm,变形量为70％时,结合强度为14N／mm。轧制过程中,新鲜金属从结合面裂纹中挤压出来,受界面摩擦力剪切作用,两新鲜金属搓合在一起形成良好结合。     

Deformation Behavior of Carbon Fiber/Al Composites with Corrugated Structure for Developing the Rolling Plate

Herein, a rolling strategy for carbon fiber (CF)/Al composites is proposed, that is, by constructing a corrugated structure of Sn-protected CFs ([CF@Sn]≈Al composites), to realize the cooperative extension of woven CFs with Al matrix deformation in the rolling process. The matching extension feasibility and structural optimization of (CF@Sn]≈Al composites are calculated based on the designed 3D numerical model of rolling system. The [CF@Sn]≈Al composites have successfully combined excellent mechanical properties while meeting the extension design of the CF reinforcement. Mechanical testing of the samples indicates that the tensile strength of the [CF@Sn]≈Al composites increases by 18.6% while the bending strength is more than 23.2% higher than that of the rolled Al matrix. The present work provides an effective method for developing the deformed CF/Al composites as rolling plate in lightweight applications.     

Influence of thermomechanical processing on superplastic forming of Mg–Al alloys

Abstract

The aim of this paper is to study the influence of the initial microstructure of several Mg–Al alloys on their superplastic formability and on their post-forming microstructure and mechanical properties. Various thermomechanical processing routes, such as annealing, conventional rolling, severe rolling and cross rolling, were used in order to fabricate AZ31 and AZ61 alloys with different grain sizes. These materials were then blow formed into a hat shaped die. It was found that the processing route has only a small effect in the formability of Mg–Al alloys or on the post-forming microstructures and properties due to rapid dynamic grain growth taking place at the forming temperatures. Nevertheless, good formability is achieved as a result of the simultaneous operation of grain boundary sliding and crystallographic slip during forming.     

Compressive behaviour of aluminium matrix syntactic foams reinforced by iron hollow spheres

Aluminium alloy syntactic foams reinforced with iron hollow spheres were produced by low pressure, liquid phase inert gas infiltration technique. Four Al alloys (Al99.5, AlSi12, AlMgSi1 and AlCu5) and Globomet grade iron hollow spheres were used as matrix and reinforcing material, respectively. The produced composite blocks were characterised according to the ruling standard for compression of cellular materials in order to ensure full comparability. The compressive test results showed plastic yielding and a long, slowly ascending plateau region that ensures large energy absorption capability. The proper selection of the matrix material and the applied heat treatment allows for a wide range of tailoring of the mechanical properties. For design purposes, the full-scale finite element method (FEM) model of the investigated foams was created and tested on Al99.5 matrix foams. The FEM results showed very good agreement with the measured values (typically within 5% in the characteristic properties and within 10% for the whole compression curve).     

塑性有限元在金属体积成形过程中应用的进展

塑性有限元法已经成为研究金属体积成形的重要方法。介绍了刚塑性有限元和弹塑性有限元的原理;综述了金属体积成形过程中锻造、挤压和轧制工艺有限元模拟的国内外最新应用进展,并分析了有限元法在不同工艺中应用的未来发展方向。最后总结了塑性有限元法在金属体积成形领域未来发展的难点和趋势。