考虑粘滞阻尼的Truss Spar频域响应分析

联合势流理论与修改的Morison方程,建立波浪作用下的Truss Spar平台运动响应计算模型。波浪激振力与相关水动力信息采用高阶边界元计算方法获得。通过数值模拟得到Truss Spar平台纵荡、垂荡和纵摇RAO,针对Morison阻力系数对响应的影响进行参数分析。计算结果显示,纵荡和纵摇仅在低频部分对阻力系数敏感。因此平台在遭受二阶波浪慢漂力作用时,粘滞阻尼将起到重要作用。对于垂荡方向,由于Truss Spar安装的垂荡板提供了较大的竖向粘滞阻尼,因此垂荡RAO受阻力系数的影响较大。     

防御船撞桥的新装置及其机理研究

从机理上区分防撞装置有弹性的(橡皮垫),弹塑性的(钢管类)和粘滞性的(大耗能、少回弹).前面两种已实现,新装置就是用第三种-粘滞性的防撞元件,它能吸收消耗掉冲击能量的70%以上.但每个粘滞性的防撞元件耗能只有几万焦耳,对于几百兆焦的大船,新装置采取的办法是吸收消耗一部分能量的同时,将船头拨开,化解撞击.为此在几百只耗能防撞元件的外面设置斜向的外钢围.新装置既能保护桥也能保护船,对于足够大的桥墩则只考虑保护船便可以了.     

粘流方法的螺旋桨尾流场数值分析(英文)

The computational fluid dynamics(CFD) method is used to numerically simulate a propeller wake flow field in open water.A sub-domain hybrid mesh method was adopted in this paper.The computation domain was separated into two sub-domains,in which tetrahedral elements were used in the inner domain to match the complicated geometry of the propeller,while hexahedral elements were used in the outer domain.The mesh was locally refined on the propeller surface and near the wake flow field,and a size function was used to control the growth rate of the grid.Sections at different axial location were used to study the spatial evolution of the propeller wake in the region ranging from the disc to one propeller diameter(D) downstream.The numerical results show that the axial velocity fluctuates along the wake flow;radial velocity,which is closely related to vortices,attenuates strongly.The trailing vortices interact with the tip vortex at the blades’ trailing edge and then separate.The strength of the vortex shrinks rapidly,and the radius decreases 20% at one diameter downstream.     

变阻抗桩纵向振动的半解析解

考虑桩周土体的三维波动效应,分析成层黏性材料阻尼土中桩顶受任意轴向激振力作用时变阻抗桩的纵向振动特性,求得桩顶频域响应解析解、复刚度和速度导纳,分析了底部土层模量变化和桩身阻抗变化对桩纵向振动特性的影响。     

Computation of the viscous hydrodynamic forces on a KVLCC2 model moving obliquely in shallow water

The viscous hydrodynamic force and moment on ships moving obliquely in shallow water axe important for ship navigation safety. In the paper, the viscous flow field around a KVLCC2 model moving obliquely in shallow water is simulated and the hydrodynamic drag, lateral force and yaw moment acting on the hull are obtained by a general purpose computational fluid dynamics (CFD) package FLUENT with shear-stress transport (SST) k-w turbulence model. The numerical computation is performed at different drift angels and water depths. The numerical results are compared with experimental results, and a good agreement is demonstrated.     

发动机硅油减振器的设计与匹配

通过对190系列发动机硅油减振器的设计与匹配研究,探索出一种硅油扭转减振器与发动机合理匹配的方法,以提高发动机曲轴工作可靠性,改进整机性能。     

粘滞阻尼器在斜拉桥减震设计中的应用

介绍了斜拉桥减震设计的思想以及粘滞阻尼器在斜拉桥减震设计中的应用,并以一座斜拉桥为例,在相同的地震波作用下,对飘浮体系、弹性约束体系和加粘滞阻尼器的半漂浮体系分别进行时程分析,比较了3种体系梁端及桥塔的水平位移、水平惯性力和桥塔的受力情况。研究表明:粘滞阻尼器能够改善斜拉桥的动力特性,不仅使得结构的位移和受力都是最小,而且提高了斜拉桥的抗震能力和耐久性,这种体系最能符合斜拉桥的减震设计思想。     

大跨自锚式斜拉-悬索协作体系桥地震响应及减震控制分析研究

基于结构非一致激励地震动方程,建立空间非线性有限元模型,探讨一致输入、行波输入下结构的地震响应.分别以主梁纵向位移、塔底内力为控制目标,研究粘滞阻尼器参数变化对结构减震效果的影响.计算结果表明:地震作用下塔底顺桥向弯矩达365.12MN.m,对自锚式斜拉-悬索协作体系桥的设计起控制作用;行波效应使得主梁跨中横向位移增大42%,横向弯矩减小14%;结构纵向位移及塔底内力在考虑行波效应后减小9%左右,安装参数合理的阻尼器使主梁纵向位移减小44%,主梁跨中弯矩和剪力减小41%,塔底纵向弯矩减小37%,达到减震效果.     

广西南宁大桥液体粘滞阻尼器设计

广西南宁大桥主桥为主跨300 m的曲线梁非对称外倾钢箱拱桥,属于飘浮体系。为了改善主桥结构的抗震性能,在主梁与肋间平台之间设置了液体粘滞阻尼器。介绍大桥液体粘滞阻尼器的设计。