滤波频率对地铁车辆转向架载荷测试影响的研究

针对地铁车辆转向架载荷测试的特点,选择了不同的滤波频率对上海轨道交通1号线车辆转向架振动加速度在线试验测试数据进行处理。结合不同的被测量,分析了滤波频率对转向架荷载测试的影响,提出了适用于地铁车辆转向架荷载测试的滤波和采样频率;转向架动力学试验中振动加速度采样频率不低于640Hz;构架垂向和纵向加速度滤波频率选择125~150Hz;架悬电机垂向、横向和纵向加速度滤波频率不低于250Hz。     

半潜式平台水动力参数敏感性分析

文章通过水动力分析软件SESAM主要计算了半潜式平台在不同的参数下的纵摇、横摇、垂荡等重要的水动力性能数据,同时通过与原来数据的比较得到了优化的结论,为新式浮式平台的设计提供一定的参考。     

单层异型钢结构大型雨篷在风荷载作用下的性能及结构布置

针对沿海地区某异形钢结构大型雨篷单层网格结构,分析了雨篷在不同荷载作用下的静力和动力性能及雨篷在各方向风荷载作用下的性能,包括雨篷刚度的影响因素、不同形式的支承、布置在不同位置的支承对刚度的影响,及不同连接方式对雨篷刚度产生的变化.研究表明：风荷载是该雨篷设计的控制因素,而恒荷载、地震作用和温度对雨篷性能的影响不大,并提出了为获得经济合理方案应采取的有效构造措施.     

自平衡试桩法在上海铁路南站工程中的应用

在钻孔灌注桩桩基工程中,为确保工程安全,需要进行静载试验。传统的静载荷试桩法费力、费时、费钱。现通过在上海铁路南站工程中进行自平衡试桩法测试桩的承载力,并与锚桩试桩法测试结果进行对比,取得了满意的结果。测试结果表明,自平衡试桩法与常用的锚桩试桩法相比,具有节约工期、节省测试费用、对施工影响小等特点。     

大型滚装船弯扭强度整船有限元分析

以大型滚装船为研究对象,采用现代的三维全船有限元分析技术及DNV船级社的SESAM软件系统,为全面研究整船弯扭强度,建立了全船有限元结构模型、质量模型、水动力计算模型;应用三维辐射—绕射理论和有限元程序进行波浪载荷的长期预报,在此基础上确定设计波参数;对全船结构有限元模型在设计波载荷作用下分析计算得到各种工况下船体结构的应力、变形响应,获得船体结构强度特点,对该类船舶的结构设计优化和强度分析有一定的参考价值,同时对其他类型船舶弯扭强度全船有限元分析有借鉴意义。     

Difference in ship motion and wave load in long and short crested irregular waves北大核心CSCD

[Objective]To investigate ship motion and load responses in realistic 3D waves and overcome the limitations of the traditional 2D wave assumption, this paper develops a method for predicting ship motion and load responses in short-crested waves. [Method]The long- and short-term responses of ship motion and load in long- and short-crested waves are numerically predicted using the spectral analysis and statistical probability methods, respectively. The influence of directional function on ship response is also numerically analyzed. Moreover, tank model tests and a large-scale model sea trial are comparatively conducted to validate the difference between ship response and statistics in long- and short-crested irregular waves. [Results]The results show that when navigating against the waves in the same sea condition, the long-crested wave assumption overestimates the statistical mean value of ship load response, but underestimates extreme load in real seas. For long-crested waves, the ship motion and acceleration power spectrum is concentrated around a certain frequency band. [Conclusion]Ship motion and load responses in realistic 3D waves are significantly different from those in 2D long-crested waves. The directional function of short-crested waves also has a significant effect on ship motion and load responses. © 2023 The Author(s).     

Wave load computation in direct strength analysis of semi-submersible platform structures

A wave load computation approach in direct strength analysis of semi-submersible platform structures was presented in this paper. Considering the differences in shape of pontoon, column and beam, the combination of accumulative chord length cubic parameter spline theory and analytic method was adopted for generating the wet surface mesh of platform. The hydrodynamic coefficients of platform were calculated by the three-dimensional potential flow theory of the linear hydrodynamic problem for platform with low forward speed. The equation of platform motions was established and solved in frequency domain, and the responses of wave-induced loads on the platform can be obtained. With the interpolation method being utilized, the pressure loads on shell elements for finite element analysis(FEA) were converted from those on the hydrodynamic computation mesh, which pave the basis for FEA with commercial software. A computer program based on this method has been developed ,and a calculation example of semi-submersible platform was illustrated. Analysis results show that this method is a satisfying approach of wave loads computation for this kind of platform.     

轴力作用下X型焊接管节点热点应力的分布规律

海洋平台中的焊接管节点的疲劳寿命是由热点应力的大小和分布决定。热点应力的大小决定了管节点在疲劳失效前所能承受的循环荷载的次数,而热点应力的位置则决定了疲劳裂纹的萌生位置和扩展方式。文中采用有限元方法分析了承受轴向拉力作用的X型焊接管节点在焊缝周围的热点应力的分布情况,通过对112个X节点进行的模型分析,研究了节点几何参数对热点应力大小和分布规律的影响。     

半潜式火箭发射平台的水动力性能

本文研究的火箭发射平台主体,为六立柱半潜型式。波高相对于特征长度为小量,考虑到波浪对平台主体大尺度结构的辐射和绕射作用,采用三维频域势流理论对其波浪载荷进行计算分析。对于横撑等小尺度构件,其直径远小于波长,波浪的绕射效应可以被忽略,而粘性作用十分重要,采用了修正的Morison方程对其求解。计算分析结果将为火箭发射平台水动力性能研究提供参考。     

大面积堆载对轨道吊桩基础的影响

由于拟建露天卷钢堆场地基土持力层为深厚淤泥及淤泥质土,大面积卷钢堆载引起土体产生的竖向及侧向位移将严重影响堆场轨道吊桩基础的安全和使用,故必须对地基土进行处理。采用有限元数值分析的方法,对未处理、水泥搅拌桩处理、堆载预压3种情况下大面积卷钢堆载对轨道吊桩基础影响进行分析,得出3种情况下桩基的受力及变形情况。通过多方面对比分析,最终确定适合本场地的地基处理方案。