拉压载荷作用下裂纹板的振动研究

该文从理论上研究了受面内拉压载荷作用下裂纹板的振动问题。考虑各种参数,比如裂纹的长度、边界条件、载荷等对基频的影响。其结果与有限元进行了对比分析,得出频率随面内拉力的增大而增大,但随面内压力的增大而减小;此外,裂纹的尺寸与边界条件对频率的影响在文中也进行了详细的分析。     

美军联合电子战消除频率冲突研究

针对电子战中的频率冲突问题,研究了美军联合电子战消除频率冲突的程序和内容,系统阐述了美军联合部队各相关部门的职责,分析了美军在联合电子战中消除电子战频率冲突的方式,为我军在未来联合作战中解决电磁频率冲突的相关问题提供参考。     

A Hybrid Heuristics for Irregular Flight Recovery

Adverse weather conditions, congestion at airports, and mechanical failures often disrupt regular flight schedules. The irregular flight recovery problem aims to recover these schedules through reassignments of flights and cancellations. In this article, we develop the classic resource assignment model for the irregular flight recovery problem, and a new hybrid heuristic procedure based on greedy random adaptive search procedure (GRASP) and simulated annealing algorithm is presented to solve this problem. As compared with the original GRASP method, the proposed algorithm demonstrates quite a high global optimization capability. Computational experiments on large-scale problems show that the proposed procedure is able to generate feasible revised flight schedules of good quality in less than five seconds.     

轻轨箱形桥梁的模态比较与桥型优化

比较箱梁不同桥型的抗扭刚度差异,优化箱梁桥型,对于国内大量建设城市轨道交通尤为重要.通过对五种轻轨箱形桥梁的有限元建模,归纳总结了五种箱形桥梁前10阶的固有频率和振型特征,并对模态分析结果进行了横向、纵向的对比,同时还研究了固有频率和结构刚度的关系,最后对轻轨箱形桥梁的桥型进行了优化.结果表明,带端隔墙和横隔板箱梁的抗...     

动态刚度矩阵在曲轴动态特性分析中的应用(英文)

应用动态刚度矩阵法分析曲轴的动态特性.曲轴被简化为一系列的连续梁单元.在给定力和位移边界条件下,得出了考虑转动惯量和剪切变形影响的空间连续梁单元的动态刚度矩阵.总动态刚度矩阵按照常规有限元方法进行组装.采用Wittrick-Wlliams(W-W)算法和常规算法分别计算了曲轴系统的特征值和特征向量.应用本文方法、有限元方法以及相关实验数据分析了4缸直列内燃机曲轴的动态特性.通过比较,验证了文中方法的有效性和精确性.     

磁浮道岔梁自振特性及瞬态响应分析

建立了磁浮道岔五跨钢结构连续梁的梁单元和板单元有限元模型,分析了道岔梁的自振特性,计算了磁浮道岔梁的瞬态响应。模态分析表明道岔梁板单元模型的前5阶扭转频率在14．2Hz至16．1Hz之间,与其现场实测值14．9Hz极为接近,道岔梁梁单元模型的扭转频率计算值明显高于实测值,道岔梁板单元模型能更为准确的反映其振动特性。瞬态响应分析表明磁浮车辆通过时道岔梁第三跨跨中挠度最大,车速240km／h时其最大值约为1．29mm。     

高墩大跨径连续刚构(梁)桥梁静力、动力性能和弹性屈曲分析

磨子潭1号桥的静力、动力性能和弹性屈曲的计算和分析结果,可从设计理论的角度为今后山区高速公路上高墩桥梁结构型式的选择和结构计算提供翔实的依据.     

Experimental study of a suspended subsea module at different positions in the splash zone

During the lifting of submerged marine modules, the highest dynamic loads occur in the splash zone. These forces are highly dynamic and cannot easily be estimated with sufficient accuracy using simple calculations or high-fidelity computational fluid dynamics because of their irregular and complex geometries. We conducted an experimental study in a wave tank to investigate the dynamics of a large subsea module in the splash zone subject to irregular waves. The experiments were conducted using a 1:8 scale model of a subsea module, similar to that designed by Offshore Oil Engineering Co., Ltd., for the subsea pipeline from the Wenchang gas fields to the Yacheng pipeline. The model was examined at five different positions relative to the free surface, from completely above the surface to fully submerged. The resulting data are analyzed in the time and frequency domains. Spectral analysis and a dynamic effect parameter are used to analyze the dynamic loads on the subsea module. Several time-domain numerical analyses are performed with different peak periods, and the tension of the sub-slings is obtained. The experimental results for the relative forces and motions of the subsea module are presented, providing a reference for the design of other similar modules and their installation and validation data for computational modeling.     

谈非规则相邻车站的信号联锁设计

针对相邻车站的特殊接轨方式,论述如何划分信号联锁分界点,围绕分界点如何进行信号联锁关系设计,最终实现债权明确、安全可靠和使用方便等功能。     

射频信号在电气化铁路隧道中的传输分析及应用

分析了射频信号沿电气化铁路隧道的传播。基于隧道壁的特性以及接触网和轨道的存在,对于应用频率、传输模式、场的表示给出了符合实际的分析。结合设计与研制的电气化铁路接触网施工安全防护用便携射频收发机在宝（宝鸡）－成（成都)铁路沿线长期应用与测试,给出了在汇龙场隧道射频传输的实际效果。研究表明,电气化铁路隧道是语音和低速数字信号传输的有效信道。