Rain-Flow and Reverse Rain-Flow Counting Method for the Compilation of Fatigue Load Spectrum     

宋玉普  王立成  李朝阳 《中国海洋工程》2001,(3):429-435

The rain-flow counting method is widely used to compile the fatigue load spectrum. The second stage counting of the rain-flow method is a troublesome process. In order to overcome this drawback, the rain-flow and reverse rain-flow counting method is proposed in this paper. In this counting method, the rule for counting of the rain-flow method is modified, so that the sequence of load-time need not be adjusted. This is a valid and useful method to count cycles and compile the load spectrum and it can be widely used in ocean engineering.  相似文献   

Prediction of Load Carrying Capacity of Corroded Reinforced Concrete Beam     

范颖芳  周晶冯新 《中国海洋工程》2004,18(1):107-118

A novel method for prediction of the load carrying capacity of a corroded reinforced concrete beam (CRCB) is presented in the paper. Nine reinforced concrete beams, which had been working in an aggressive environment for more than 10 years, were tested in the laboratory. Comprehensive tests, including flexural test, strength test for corroded concrete and rusty rebar, and pullout test for bond strength between concrete and rebar, were condueted. The flexural test results of CRCBs reveal that the distribution of surface cracks on the beams shows a fractal behavior. The relationship between the fractal dimensions and mechanical properties of CRCBs is then studied. A prediction model based on artificial neural network (ANN) is established by the use of the fractal dimension as the corrosion index, together with the basic intbrmation of the beam. The validity of the prediction model is demonstrated through the experimental data, and satisfactory resuits are achieved.  相似文献   

底部浮泥表层推移速度分布的ADCP—GPS估测方法   总被引：3，自引：0，他引：3  

吴中  陈力平等 《海洋工程》2002,20(4):85-88

ADCP对底跟踪走航观测的流速数据中包含水体底部浮泥、底沙运动信息,对比GPS定位方法算出的水体流速数据可以分离出浮泥相对于GPS定位的运动信号,从而达到对底质推移观测的目的。  相似文献   

Two-Dimensional Mathematical Model of Tidal Current and Sediment for Oujiang Estnary and Wenzhou Bay   总被引：1，自引：0，他引：1  

LU  Yongjun 《中国海洋工程》2002,16(1):107-122

A 2-D mathematical model of tidal current and sediment has been developed for the Oujiang Estuary and the WenzhouBay. This model accomodates complicated features including multiple islands, existence of turbidity, and significant differ-ence in size distribution of bed material. The governing equations for non-uniform suspended load and bed load transport arepresented in a boundary-fitted orthogonal curvilinear coordinate system. The numerical solution procedures along with theirinitial conditions, boundary conditions, and movable boundary technique are presented. Strategies for computation of thecritical condition of deposition or erosion, sediment transport capacity, non-uniform bed load discharge, etc. are suggested.The model verification computation shows that, the tidal levels computed from the model are in good agreement with the fielddata at the 18 tidal gauge stations. The computed velocities and flow directions also agree well with the values measuredalong the totally 52 synchronously observed verticals distributed over 8 cross sections. The computed tidal water throughputsthrough the Huangda‘ao cross section are close to the measured data. And the computed values of bed deformation fromYangfushan to the estuary outfall and in the outer-sea area are in good agreement with the data observed from 1986 to 1992.The changes of tidal volumes through the estuary, velocities in different channels and the bed form due to the influence of thereclamation project on the Wenzhou shoal are predicted by means of this model.  相似文献   

An Analysis on Limit Load for Corroded Submarine Pipelines     

谭开忍  肖熙 《中国海洋工程》2006,20(3):483-490

1 .Introduction Submarine pipelines are one of the safest and the least environmentally disruptive means for ma-rine gas or oil transport . With the development of exploitation of submarine oil or gas ,the safety ofsubmarine pipelines has becomethe major …  相似文献   

Treatment of Hydrodynamic Loading for Random Sea State     

Anjan Sarkar  Suhail Ahmad  T. K. Datta M. Tech. Student Assistant Professor 《中国海洋工程》1996,(3)

- In order to employ cost effective frequency domain analysis for off-shore structures treatment of hydrodynamic loading is essential. Drag and inertia dominated, resonating and antiresonating cases under random sea states are analyzed to highlight the implications and relative merits of four salient linearization techniques.  相似文献   

蚀变岩的蠕变特性研究   总被引：1，自引：0，他引：1  

王旭东  付小敏 《工程地质学报》2008,16(1):27-31

以某水电站工程项目为依托,利用自行研制的试验仪器对大量的蚀变岩做了单轴压缩流变试验。通过对试验数据的处理和分析,得到了该种岩石的流变,并对蚀变岩的蠕变特性进行了分析总结,为工程设计提供了试验依据。  相似文献   

爆破震动对某边坡稳定性影响的数值模拟   总被引：2，自引：0，他引：2  

赵宝云  刘保县  万贻平 《工程地质学报》2008,16(1):59-62

爆破震动是影响边坡稳定性的一个重要因素之一。结合实际工程文章利用了拉格朗日有限差分法FLAC程序对爆破震动作用下某边坡进行了数值模拟。讨论了利用FLAC进行边坡动力分析时设置边界条件设置、动力时程的合成、输入以及转化,阻尼的合理选取。从位移场和速度场进行了详细的动力分析。获得该边坡爆破震动特征及位移场、振动速度场的变化规律。研究成果对保证边坡安全具有较好的指导作用。  相似文献   

PDC钻头切削齿破岩载荷规律的分析     

许爱 《探矿工程》2006,33(7):59-61

对PDC钻头冠部形状及不同的布齿密度和切削齿在不同的磨损状态下对PDC钻头切削齿受力的影响进行了分析；用相邻的3个切削齿之间的关系(不同的切削齿与切削齿之间的径向距离和切削齿之间的高度差)来分析PDC钻头冠部形状和切削齿布齿密度对切削齿受力的影响，以及将切削齿的磨损状态简化成与切削齿在钻头上装配方向垂直的平面来分析切削齿磨损状态对切削齿受力的影响。  相似文献   

自重湿陷性黄土地区桩基设计探讨          下载免费PDF全文

徐建红 《探矿工程》2006,33(9):7-8

根据自重湿陷性黄土的特点、《湿陷性黄土地区建筑规范》（GB50025—2004）和《建筑桩基技术规范》（JGJ94—94）中关于桩基设计的对比分析，通过自重湿陷性黄土场地工程实例分析计算，依据负摩擦产生的机理——中性点理论，论述了自重湿陷性黄土场地中桩基设计应考虑中性点，而不应全部计入负摩阻的观点。  相似文献