某型内燃机闭环控制减振的仿真研究

内燃机自身的振动是重型军用车辆主要的振动和噪声源,对其进行有效的振动控制十分重要.但由于内燃机系统结构的复杂性,研究其振动和噪声控制比较困难.针对某型内燃机系统,采用Matlab软件的Simulink工具,建立了整个系统的动力学仿真模型,并分别对该模型进行简谐、白噪声信号扰动下的减振控制研究,控制方法采用闭环数字PI策略.系统输出转矩和转速的曲线结果表明减振具有明显的效果.     

DAE for Frictional Contact Modeling of Constrained Multi-Flexible Body Systems

A general formulation for modeling frictional contact interactions in a constrained multi-flexible body system is outlined in this paper. The governing differential-algebraic equations (DAE) for the constrained motion contains not only a frictional term but also, the unknown contact conditions. These contact conditions are characterized by a set of nonlinear complementarity equations. To demonstrate the model, a falling-spinning beam impacting a rough elastic ground with damping is solved and comparison with Stewart-Trinkles' results provided.     

SHS复合管内衬陶瓷层残余应力分析

经陶瓷材料弹性力学计算,发现分布于陶瓷层中的压应力场强度取决于钢管与陶瓷层的结合强度及陶瓷层壁厚,而分布于陶瓷层中的热应力场强度主要取决于陶瓷层冷却过程中的温度梯度与陶瓷层壁厚.     

理论研究方法在膜超(微)滤研究中的应用

在对超(微)滤的过滤性能及过程的研究中，实验研究作出了很多贡献，但实验研究存在着结论对具体实验体系有很大依赖性、研究费用较高等缺点．介绍几种较经典的扩散模型和流体动力学模型及其建模思路、适用范围和存在问题；提出借助理论分析和计算方法设计实验，再根据实验数据利用人工神经网络建立普用性模型的新方法、对于方程的求解，介绍了简化法、摄动法、数值计算与模拟等方法的特点及其在超(微)滤研究中的应用，认为用数值计算的方法研究超(微)滤机理及膜器优化设计必将成为今后超(微)滤研究的重要方向之一．     

控制厚度分布的正反向超塑胀形的有限元分析

为研究正反向超塑胀形工艺对厚度分布的影响,应用商业有限元软件MARC对带有凹槽的深盒形7475合金零件正反向超塑胀形过程进行了有限元模拟,并对不同工艺条件下成形后零件的壁厚分布结果进行了分析.研究表明:正反向超塑胀形工艺是控制成形零件壁厚的有效途径,通过优化压力-时间曲线和反向胀形模具形状,明显改善了零件的厚度分布,达到了零件的设计要求;后处理直观地显示了该零件正反向超塑胀形的全过程,为成形提供了合理的方案;零件变形各阶段的应变速率控制在7475合金的应变速率范围内,证明压力-时间曲线设计合理.     

基于GPIB总线的自动校准系统的设计

针对某检测设备的使用维护现状,文章介绍了该检测设备的基于GPIB总线和DAQ虚拟仪器技术的自动校准系统的硬件架构组成,以及模块化和公共数据库的软件设计思想;并对射频信号显示测量不易等问题设计了解决算法.最后简要介绍了该系统的特点和现实意义.     

鞍钢11号高炉开炉达产及强化实践

鞍钢11号高炉(2580m3)第一代炉役于2001年8月15日停炉大修,第二代炉役于2001年12月16日开炉.本次开炉强调了精料是强化的基础;设备是强化的保证;上下部调剂是强化的关键;大风量、高顶压、富氧及降低生铁含硅量是强化的有效措施等原则,使高炉顺利达产.到2002年8月,利用系数达到2.344t/(m3·d).     

Deformation induced Nanostructure and texture in MP35N alloys

The macro-texture was related to the nano-platelets formed during the rolling deformation of a Co-Ni-Cr-Mo alloy (MP35N) with low stacking fault energy. The deformed materials showed {011}(533) texture but also had {011}(211) and {011}(100) texture components. The {011}(533) component reached the maximum at 74% reduction-in-area. Further deformation of the material to 80% decreased the intensity of the {011}(533) component. The cold deformation introduced platelets of a few atomic layer in thickness and less than 100 nm in diameters. The habit planes of the platelets were identified to be {111}, which were perpendicular to both the rolling and {011} crystallographic plane. Therefore, the tensile strain in the rolling direction assisted formation of the platelets, which were identified as stacking faults. A high density of nano-platelets and dislocations strengthened materials and influenced the plastic deformation behaviors and texture evolution. Thus, the MP35N developed slightly different textures from other low stacking fault energy materials. The maximum at {011}(533) was related the nanoplatelets and stacking fault energy. The {011}(112) and {110}(001)components could be linked to the low stacking fault energy.     

Rod-like β-FeSi2 phase grown on Si (111) substrate

Pure Fe with coverage of 0.5-2.0 nm was deposited on Si (111) 7×7 surfaces by reactive deposition epitaxy (RDE) in an integrated ultrahigh vacuum (UHV) system. Transmission electron microscopy (TEM) confirmed that the as-deposited epitaxial phase exhibits rod-like and equilateral triangular morphology. The as-deposited phase was identified as c-FeSi₂ by electron diffraction and high-resolution transmission electron microscopy. It was found that there exists lattice distortion in epitaxial c-FeSi₂ phase. Upon annealing at 1073 K, the metastable c-FeSi₂ transforms into equilibrium β-FeSi₂ phase, the latter inherits completely the morphology of c-FeSi₂ phase. Based on RDE and subsequent annealing, a new fabrication technique to grow rod-like semiconducting β-FeSi₂ on a Si substrate has been proposed in the present work.     

钢筋砼柱二次环抱牛腿抗剪承载力研究

在对二次环抱牛腿粘结面进行受力分析的基础上，利用新旧混凝土粘结抗剪强度的试验研究成果，建立二次环抱牛腿粘结面的抗剪承载力公式，其中短牛腿公式经工程实例验证正确可行，弥补了现行技术规范的欠缺，可供设计参考．