机动管线水底裸管铺设稳管方式分析比较

机动管线由一根根的管子用连接器或自身阴阳头连接而成,与固定管线相比,在结构形式、铺设方法、使用周期等方面有许多不同,其稳管方式具有独特性。对机动管线水底裸管铺设的稳管方式进行分析,建立管线集中压载稳管和均布压载稳管的数学模型,通过力学计算对两种压载方式进行比较,确定管线稳定的最优方式。提出应用均布压载方式的稳管方法并进行对比,探讨更适于机动管线的水底铺设形式。     

计算脉动风作用下拉索反应的一种新方法

提出了Ansys基于一点加速度时程分析方法,并用此方法对滨州黄河大桥最长的一根斜拉索N26进行脉动风荷载作用下的动力计算,包括计算原理和建模过程,并与实测结果进行对比。     

全并联AT供电牵引网故障测距研究

以京津客运专线为实例,针对全并联AT(Auto-transformer)供电牵引网所有运行方式,分析各种故障类型,确定测距原理,得到测距方程.同时,给出了用仪表测量到的电气量计算出测距方程中所需物理量的方法.本文可直接指导实际故障测距装置的研制.     

Numerical investigation on effect of the relative motion of stock/switch rails on the load transfer distribution along the switch panel in high-speed railway turnout

In railway turnout, the stock rail and switch rail are separated to enable the vehicle changing among the tracks, and they are provided with different rail resilience level on the baseplate. Therefore, there will be vertical relative motion between stock/switch rails under the wheel loads, and the relative motion will affect consequentially the wheel–rail contact conditions. A method is developed to investigate the effect of the relative motion of stock/switch rails on the load transfer distribution along the switch panel in high-speed railway turnout. First, the rigid wheel–rail contact points of stock/switch rails are calculated based on the trace line method, and then the contact status is determined by the presented equations, finally, the distribution of wheel–rail contact forces of stock/switch rails is obtained based on the continuity of interface displacements and forces which using an approximate surface deformation method. Some parametric studies have been performed, such as the lateral displacement of wheel set, the vertical contact forces, the wheel profiles and the vertical stiffness of rail pad. The results of the parametric study are presented and discussed.     

液压联轴节静摩擦特性分析

提取材料的表面特征信息,建立特征指标与摩擦副间静摩擦系数的关系,能够更加深刻的揭示摩擦的本质,为工艺技术和最优工况的选择提供依据或参考。本文通过多因素耦合分析的方式,探讨摩擦系数与影响因素(载荷、粗糙度、硬度)之间的关系。研究结果表明,材料表面粗糙度是影响静摩擦系数的核心因素,对于干摩擦工况,粗糙度对摩擦系数结果的影响占据了主导地位,硬度与工作载荷对摩擦系数的影响相当。     

横向拓宽斜交板梁桥荷载横向分布系数研究

采用有限元分别对正交及斜交板梁桥拓宽前后的各主梁荷载横向分布系数进行了计算,其结果表明正交板梁桥拓宽前后新旧主梁的横向分布系数均相差不大,而斜交时部分旧梁在拓宽后横向分布系数增大,拓宽后新梁的横向分布系数比旧梁大。因此斜交板梁桥拓宽设计应注意提高新梁的承载力,并对旧梁进行加固处理。     

Progressive collapse analysis of ship hull girders subjected to extreme cyclic bending

This paper introduces a novel analytical method to predict the buckling collapse behaviour of a ship hull girder subjected to several cycles of extreme load. This follows the general principles of the established simplified progressive collapse method with an extended capability to re-formulate the load-shortening curve of structural components to account for cyclic degradation. The method provides a framework for assessing residual hull girder strength following a complex series of unusually extreme load events where the wave induced bending moment rises close to, or even surpasses, the monotonic ultimate strength. These load events may be sequential, such as might be caused by a series of storm waves, or they may occur as a collection of discrete events occurring over a longer period. The extreme cyclic bending amplifies the distortion and residual stress initially induced by fabrication in the flanges of the girder, which results in a deterioration of the residual ultimate strength. Validation is firstly completed through a comparison with previously published experimental work and secondly via comparison with numerical simulation on four ship-type box girders using the nonlinear finite element method.     

横向载荷作用下小水线面双体船结构校核与优化

采用有限元仿真方法对一艘新型小水线面双体船进行强度校核,研究该船形在横向载荷作用下的结构强度和应力分布特性,进而给出结构优化设计方案,在确保结构安全的基础上达到严格控制重量的目的,形成的校核流程方法及优化设计方案可为同类船舶提供设计与校核指导。     

浸水条件下前期荷载对砂岩颗粒料压缩-回弹特性影响

压缩-回弹特性是地基处理及基坑工程中沉降及回填变形分析的重要参考依据。由于砂岩颗粒料属颗粒类材料,浸水时前期荷载及干密度影响其压缩-回弹特性;采用应力控制式三联杠杆(高压)固结仪,探究浸水24 h后前期荷载及干密度对砂岩颗粒料压缩-回弹特性影响。结果表明:干密度相同时,随着前期荷载增加,砂岩颗粒料压缩特性逐渐减小;在相同卸荷比条件下,回弹率逐渐降低;前期荷载相同时,砂岩颗粒料压缩特性与回弹特性均随干密度增大而逐渐减小;砂岩颗粒料塑性应变随前期荷载增加、干密度增大而逐渐减小。     

波浪作用下双排圆筒结构受力特性

依托阿尔及利亚矿石码头项目,提出一种新型的双排圆筒结构,采用Abaqus有限元分析软件对其波峰作用下的结构拟静力非线性响应进行数值分析。对于两排圆筒间采用简支板连接及采用混凝土厚板连接的两种方案,后者更可以保持变形的协调性,基顶应力的最大值也更小,且连接板的强度要求不难满足,但其造价较高。简支板方案中,对于连接板缝里填充柔性材料与不填充柔性材料两种情况,前者的填料土压呈现上大下小的线性分布,后者则相反,且连接板传递的荷载会占较大的比例,基顶应力也更大。