整体道床60kg/m钢轨12号5m间距交叉渡线道岔刚度均匀化探讨

介绍整体道床交叉渡线道岔刚度均匀化的研究意义。交叉渡线道岔和单开道岔相比结构更为复杂,为了研究其轨道刚度分布规律,以整体道床60 kg/m钢轨12号5 m间距交叉渡线道岔为例,建立交叉渡线道岔的轨道刚度有限元计算模型。通过计算分析得到刚度均匀化之前轨道刚度分布规律,表明道岔横向和纵向均存在较大的刚度不平顺。探讨刚度均匀化的原则和措施,提出交叉渡线道岔刚度均匀化的实现方法。刚度均匀化之后,直向和侧向过岔的轨道整体刚度沿线路纵向基本呈均匀分布,可以满足高速铁路和城际铁路在站线或折返线的运输组织需要。     

Ultimate strength assessment of stiffened panel under uni-axial compression with non-linear equivalent single layer approach

Steel stiffened panels are widely used in engineering design and construction. However, numerical modeling and analysis effort for a three-dimensional (3D) stiffened panel may be notable, especially for the ultimate limit state of ship structures. Therefore, a homogenization method is outlined that transforms 3D stiffened panel into an Equivalent Single Layer (ESL) concerning the same mechanical behavior. ESL stiffnesses are obtained with a unit cell analyses based on stiffened panel where periodicity is imposed with boundary conditions based on a first-order shear deformation theory (FSDT). Stiffnesses were determined from the first derivative of a membrane force and bending moment obtained with numerical simulations. The effect of initial imperfection shape was included in the analysis to account for local and global buckling behavior. ESL with non-linear stiffness was implemented in Abaqus UGENS subroutine, allowing incremental evaluation of stiffness. Ultimate strength prediction of a steel grillage model with ESL finite element analysis was in excellent agreement with detailed 3D FEM analysis. The key in this analysis was consideration of non-linear ESL stiffness as linear analysis was unable to detect the point where ultimate strength capacity of the grillage was reached.     

客车企业同质化趋势下的差异化策略

客车制造技术的日趋成熟,将导致产品“同质化”现象的发生。本文具体阐述产品同质化对企业,特别是中小企业发展所带来的不良影响,并介绍了企业进行差异化的方法和策略。     

Design of central symmetric lattice structure for ocean engineering based on fluid-solid-interaction

Some structures that constitute underwater vehicles and other ocean engineering structures, such as the shell of underwater vehicles, shafting of power systems, compressor impellers and propeller hubs, all have central symmetric or rotationally symmetric cross sections. In this paper, a kind of central symmetric lattice is designed. The lightweight design of the above structure with this lattice can significantly reduce the weight of the structure on the premise of reducing the static response of the structure. Combined with the ANSYS Parameter Design Language (APDL), the homogenization method is used to analyze the static response of the rotationally symmetric lattice structure and the parallel pattern lattice structure under pressure. The fluid load (pressure) of impeller is calculated by CFX. The results show that the structural stress of the central symmetric lattice structures with the same volume fraction is smaller than that of parallel pattern lattice under the same load when the rotationally symmetric structures have the same form. The application of the homogenization method proves that the above conclusions also improve the efficiency of the static response calculation of the central symmetric lattice structure. The design and research methods in this paper provide technical support for the realization of lightweight design of small and medium-sized underwater rotationally symmetric structures.