Finite element buckling analysis of rotationally periodic laminated composite shells

A finite element (FE) buckling analysis of rotationally periodic laminated composite shells is performed in this paper. Because the buckling mode of such structures is characterized as rotationally periodic, a corresponding FE buckling analysis scheme is proposed to reduce the computational expenses. Moreover, a new kind of relative degrees‐of‐freedom element is developed, which can be connected to other solid elements with ease and can yield satisfactory results with a relatively coarse FE mesh. Numerical results of two laminated cylindrical shells subjected to lateral pressure are compared with theoretical ones. The good agreement of them shows the validity of this new computational strategy. Finally, a practical structure is analysed to demonstrate the advantage of this method. Copyright © 2001 John Wiley & Sons, Ltd.     

气—固多相同轴射流的数值模拟和试验

本文提出了一个新的气-固多相湍流运动的模型(脉动频谱随机颗粒轨道模型),它计及了湍流涡团对颗粒扩散作用,并通过体平均方法求出颗粒的速度场和浓度场。同时建立了气-固多相射流试验台,采用激光衍射仪、高速变色频闪摄影法等对气-固多相同轴射流进行了实验研究。实验和上述模型模拟的结果吻合较好。     

利用熔渣规则溶液模型计算渣铁间S、P分配比

利用Lumsden熔渣规则溶液模型能够计算渣中各组份的活度系数，从而能够用于计算渣铁间S、P分配比．     

冲积河湾蠕动过程的试验研究

冲积河湾儒动过程是个非常复杂的问题，本文从试验的角度，探讨了冲积河湾蠕动的过程。主要内容包括：泥沙条件一定水力条件不同时河岸冲刷下冲积河湾蠕动的试验，水力条件一定泥沙条件不同时冲积河湾河床冲刷的试验，河湾流路曲线等。     

安哥拉重质原油生产1号高等级道路沥青的研究

在对安哥拉重质原油性质及制备1号高等级道路沥青进行了试验研究的基础上提出了加工安哥拉重质原油有生产1号高等级道路沥青的建议。     

BIFURCATIONS AND INSTABILITIES IN FRACTURE OF COHESIVE-SOFTENING STRUCTURES: A BOUNDARY ELEMENT ANALYSIS†

The “cohesive-crack model” is adopted, together with the hypotheses of small deformations and linear elasticity outside the process zone or “craze”, for the simulation of fracture processes in structures of concrete-like materials. A “direct”, collocation, multidomain boundary element method is employed and shown to be computationally effective in the considered situations, which are characterized by non-linearity on interfaces only. Iterative algorithms for the direction search and interface adjustment in propagation analysis and for the determination of the response to a craze-tip advancement are developed and numerically tested. Softening as an instabilizing factor embodied in the cohesive-crack model may give rise to path bifurcations (“equilibrium branching”), instability under load control and intrinsic (“snapback”) instability. These phenomena are analysed by the proposed boundary element procedure and discussed.     

四边形单元面积坐标的微分和积分公式

构造四边形单元时，应用面积坐标方法有其优点。文献［１］系统地论述了四边形单元面积坐标理论，本文是文献［１］的续篇，补充论述采用四边形单元面积坐标时的微分和积分公式。采用三角形单元面积坐标时的微分和积分公式是其特殊情况。应用面积坐标方法时，易于得出四边形单元刚度矩阵的积分显式，无需依赖于数值积分，这个优点是采用四边形等参坐标时所不具备的。     

稻草低温燃烧过程中床料聚团机理的实验研究

在小型燃煤鼓泡流化床上对稻秆低温燃烧的聚团现象进行了试验研究并对其机理进行了探讨.对所取床料样品的分析结果表明,床料中碱金属主要以钾并以KCI和K2SO4水溶性钾方式存在,且随着燃烧时间的增长碱金属在床料中呈增加趋势,同时床料聚团颗粒增多.对稻秆在650℃和700℃成灰的XRD检测也表明,稻秆在该温度范围内燃烧后灰的物相主要是KCI、K2SO4和SiO2,而KCI和K2SO4的两相低温共熔温度约为684℃,说明KCI和K2SO4低温共溶对稻秆低温燃烧床料聚团具有重要作用.     

静电除尘用脉冲电源拓扑研究

对一种静电除尘用脉冲电源高压拓扑进行了研究,通过模态分析谐振状态及谐振后的震荡转态,研究耦合电感、耦合系数及谐振腔电阻对静电除尘器电源输出电压的影响,优化设计耦合电感及耦合系数。通过理论分析,推导出各部分激励对负载的传递函数表达式,并绘制三维变参数曲面图进行系统参数分析,最后搭建1.5 k V的脉冲电源系统,验证静电除尘器电源拓扑的工作原理及理论分析设计的正确性。