基于模拟退火算法的潜艇结构系统可靠性计算   总被引：9，自引：0，他引：9  

吴亚舸刘从军  吴剑国 《海洋工程》2003,21(3):24-28

针对结构系统可靠度计算中重要样本函数选择的困难，提出了应用模拟退火算法的自适应的重要样本法，并根据结构系统可靠性计算的特点，给出了适宜的模拟退火过程的冷却进度表。潜艇耐压结构系统可靠性分析的算例表明，本方法可有效地解决非线性失效方程的工程结构系统可靠度的计算问题。  相似文献   

新型三维内波及分层流水槽系统     

徐肇廷  沈国谨  王伟  王爱群 《中国海洋大学学报(自然科学版)》2002,32(6):868-876

本文提供了作者研制的三维内波及分层流水槽系统的背景技术资料。经源致三维内波的实验证实 ,利用该水槽系统中的双缸制取分层水系统可快速制取所需的分层水 ,不必利用分子扩散而 1次得到预先设置的密度剖面。同时 ,还介绍了利用该水槽系统进行的 1个典型的源致内波的内波增阻实验。从所获得的增阻实验结果得知 ,对于一给定的分层、拖曳速度和水下回转体 ,存在唯一 1个内Froude数使得强迫源受到最大的内波增阻。大量的实验证实 :该水槽系统是研究三维自由和强迫内波的 1个基本实验系统。  相似文献   

Efficient computation method for two-dimensional nonlinear waves     

Wang Ke  Kang Haigui 《海洋学报(英文版)》2001,20(2):281-297

I~IOWNUmerics wave tank is a ~ tOOl by which variouS nonlinear wave - ac interactionpwhleln can be treated in time domain. As the face stage, we f~ our efforts on the devious of an effita saution tee~ of fully nofor waves. aam numtried of water - wavesconnected PwhlemS, es~ in a wave tank, is alwayS comas Of PartS: wave generation, P~ and a~. The effi~ Of a nUm~ wave tankdepends not Only on the qwhty Of the wave abotion tecboaue, which allowS the lOng times~ and keePS finite tank leng…  相似文献   

液舱晃荡载荷计算与强度校核系统研究     

赵吉  许一敏  程成  冷文浩 《海洋工程》2015,33(5):1-9

随着薄膜型LNG运输船的需求量不断增加,晃荡载荷已成为船舶安全性研究的重要内容之一。本文结合中国船级社规范所推荐的公式,对薄膜型LNG船晃荡水平的载荷进行研究,提出载荷计算方法和流程,在MSC.patran的基础上结合二次开发语言PCL,设计了一套晃荡载荷计算与校核系统。该系统对有限元模型进行前后处理,设计了舱室识别算法来搜索晃荡载荷的作用域,实现薄膜型LNG船晃荡载荷的自动计算与施加,完成屈服强度评估。通过算例测试证明本系统自动计算结果的有效性和准确性,可以为工程设计人员大大节约工作量,大幅度提高工作效率。  相似文献   

波浪作用下三角型人工鱼礁水动力特性数值模拟与实验验证   总被引：1，自引：0，他引：1  

赵云鹏  王晓鹏  董国海 《海洋工程》2015,33(6):52-61

人工鱼礁在波浪作用下水动力特性的研究对于人工鱼礁的工程安全与设计具有非常重要的意义。基于有限体积法,采用推板造波形式,通过利用VOF方法求解波面的方式建立了模拟人工鱼礁与波浪相互作用的三维数值波浪水槽。基于该数值模型研究了波浪作用下三角型镂空人工鱼礁的受力情况,并与物理模型实验结果进行比较,结果显示模拟得到的人工鱼礁受力和波浪形态均与实验结果吻合良好。根据数值模拟结果,拟合出波浪作用下人工鱼礁的水动力系数。单体三角型镂空人工鱼礁的速度力系数Cd随着Kc数、Re数的增加呈现减小的趋势;惯性力系数Cm则随着Kc数、Re数的增加呈现波动趋势。数值模拟结果显示在一个波浪周期内,人工鱼礁周围产生了较强的上升流和回流,其内部产生了明显的涡旋结构。研究结果为人工鱼礁的设计优化提供了理论依据。  相似文献   

必须重视大型石油储罐的抗震问题   总被引：2，自引：0，他引：2  

韦树莲 《国际地震动态》1995,(3):17-21

地震灾害是各种自然灾害中最大的一种灾害，而大型石油储罐则是石油化工设备中震害最大设备，因此必须重视大型油罐的抗震问题，本文从油罐的几何形状的荷载特征等方面说明了油罐震害之所以特别大的主要原因；指出了油罐的主要震害；并从四个方面说明了油罐的抗震理论是非常复杂的。  相似文献   

Wavelet‐based non‐stationary seismic rocking response of flexibly supported tanks     

Pranesh Chatterjee  Biswajit Basu 《地震工程与结构动力学》2004,33(2):157-181

The non‐stationary rocking response of liquid storage tanks under seismic base excitations including soil interaction has been developed based on the wavelet domain random vibration theory. The ground motion has been characterized through statistical functionals of wavelet coefficients of the ground acceleration history. The tank–liquid–foundation system is modelled as a multi‐degree‐of‐freedom (MDOF) system with both lateral and rocking motions of vibration of the foundation. The impulsive and convective modes of vibration of the liquid in the tank have been considered. The wavelet domain coupled dynamic equations are formulated and then solved to get the expressions of instantaneous power spectral density function (PSDF) in terms of functionals of input wavelet coefficients. The moments of the instantaneous PSDF are used to obtain the stochastic responses of the tank in the form of coefficients of hydrodynamic pressure, base shear and overturning base moment for the largest expected peak responses. Parametric variations are carried out to study the effects of various governing parameters like height of liquid in the tank, height–radius ratio of the tank, ratio of total liquid mass to mass of foundation, and shear wave velocity in the soil medium, on the responses of the tank. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

立式钢制储罐基于地震损伤性能的抗震设计方法     

孙建刚  周利剑  魏志真 《世界地震工程》2004,20(2):122-128

针对立式钢制储罐在强烈地震作用下会产生不同程度的损伤的特点，遵循抗震设计规范的“小震不坏，中震可修，大震不倒”的抗震设计原则，结合三水准烈度，提出了储罐的地震损伤性能目标，并给出了基于地震损伤性能的抗震设计方法。所提出抗震设计方法，更加准确地考虑了储罐的提离问题。  相似文献   

An investigation of tuned liquid dampers equipped with damping screens under 2D excitation     

M. J. Tait  A. A. El Damatty  N. Isyumov 《地震工程与结构动力学》2005,34(7):719-735

This paper reports on the results of a study conducted on tanks partially filled with water, representing tuned liquid dampers (TLD), subjected to both 1D and 2D horizontal excitations. The sloshing response of the water in the tank is characterized by the free surface motion, the resulting base shear force, and evaluation of the energy dissipated by the sloshing water. A 1D non‐linear flow model capable of simulating a TLD equipped with damping screens is employed to model a 2D TLD. Application of this particular model requires the assumption that the response is decoupled and can be treated as the summation of two independent 1D TLDs. Results from the non‐linear flow model are compared with the 2D experimental shake table test results leading to a validation of the decoupled response assumption. This attractive decoupled response property allows square and rectangular tanks to be used as 2D TLDs, which can simultaneously reduce the dynamic response of a structure in two perpendicular modes of vibration. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Model tank electrical resistivity characterization of LNAPL migration in a clayey-sand formation     

A. A. Adepelumi  A. A. Solanke  O. B. Sanusi  A. M. Shallangwa 《Environmental Geology》2006,50(8):1221-1233

A modeling tank time-lapse 2D electrical resistivity experiment was undertaken to model the leakage of petroleum products from underground pipelines into a clayey-sand aquifer. Numerical modeling was employed to simulate the electrode arrays that would resolve the post-leakage subsurface image most efficiently. Of the four arrays tested, the dipole–dipole array proved most effective and was adopted for the laboratory studies. Pre-injection surveys were conducted to assist in discriminating between features caused by hydrocarbon accumulation and those due to natural geologic variability. Subsequently, controlled injection of diesel–oil into the model tank was undertaken at regular intervals over a period of 3 days. Experimental evidence obtained from the studies indicates that high resistivity build up few hours after injection is directly related to hydrocarbon accumulation. Rather than biodegradation of the hydrocarbon, a more probable explanation for the observed decrease in resistivity observed a few hours after injection is simply that the hydrocarbons drained to a deeper level after pooling temporarily at a shallow level.  相似文献