Fatigue Behavior of Plain Concrete Under Biaxial Compression: Experiments and Theoretical Model     

ZHU  Jin-song 《中国海洋工程》2003,17(4):617-630

The effects of different lateral confinement stress on the fatigue behavior of and cumulative damage to plain concrete are investigated experimentally. Eighty 100 mm x 100 mm x 100 mm specimens of ordinary strength concrete are tested under constant- or variable-amplitude fatigue loading and lateral confinement pressure in two orthogonal directions. A fatigue equation is developed by modifying the classical Aas-Jakobsen S-N equation for taking into account the effect of the confined stress on fatigue strength of plain concrete. The results of variable-amplitude fatigue tests indicate that the linear damage theory proposed by Palmgren and Miner is unreasonable in the biaxial stress state. A nonlinear cumulative damage model that could model the effects of the magnitude and sequence of variable-amplitude fatigue loading and lateral confinement pressure is proposed on the basis of the evolution laws of the residual strains in the longitudinal direction during fatigue tests. The residual fatigue life predic  相似文献   

Cyclone formation and development in the Antarctic Prydz Bay     

Xie Simei  Mei Shan  Liu Kewei  Wei Lixin 《海洋学报(英文版)》2002,21(1):45-54

Using meteorological data of field observation in 1990 - 2000, especially polar orbit high-resolution NOAA satellite cloud maps received from the Antarctic expedition vessel since 1997, the formation and development of the Prydz Bay cyclone are studied in this paper. Some new viewpoints are suggested such as: when surround-polar cyclone enters the Prydz Bay, it can also intensify and develop in summer; cyclone can also develop in the easterlies in this bay. These view points revise old uncom-plete view point that the Prydz Bay is a burial ground of cyclone, and also further consummate formation-development theory of surround-cyclone in the Antarctic westerlies and cyclone in the Antarctic easterlies. In this paper, the mechanism of ice-air-sea interaction in the Prydz Bay is studied, and the physical process of cyclone formation-development is explained. By use of wholly dynamic transportation method, an energy exchange case of a cyclone, which explosively developed after entering the Prydz Bay, is calcu  相似文献   

秋季黄海中南部鱼类群落对饵料生物的摄食量   总被引：8，自引：0，他引：8  

薛莹  金显仕  赵宪勇  梁振林  李显森 《中国海洋大学学报(自然科学版)》2007,37(1):75-82

研究鱼类与饵料生物之间食物定量关系进而为多鱼种资源评估提供依据,2000~2002年秋季(10~11月)在黄海中南部海域进行了定点底拖网调查,应用Eggers模型,计算了带鱼(Trichiurus lepturus)、小黄鱼(Pseudosciaena polyactis)、黄(Lophius litulon)、细纹狮子鱼(Liparis tanakae)等23种鱼类在秋季对饵料生物的摄食量。结果表明:黄海中南部23种鱼类在秋季对饵料生物的总摄食量约为309万t,其中,鱼(Engraulis japonicus)的摄食量最高(在250万t以上),占总摄食量的80.9%。中上层和底层鱼类对饵料生物的摄食量分别为262万t和47万t左右,占总摄食量的84.7%和15.3%,鱼和细纹狮子鱼分别是中上层和底层鱼类中最主要的捕食者。磷虾类是中上层鱼类最主要的食物来源,其次是桡足类、端足类和毛颚类;虾类和鱼类是底层鱼类最主要的食物来源,其次是磷虾类。太平洋磷虾(Euphausia pacifica)、中华哲水蚤(Calanus sinicus)、细长脚虫戎(Themisto gracilipes)、脊腹褐虾(Crangon affinis)和鱼同时是黄海中南部被摄食量最高的5种饵料生物,它们被摄食的生物量之和约为233万t,占总摄食量的75.5%。  相似文献   

黄骅电厂取水河段取水特性的数模与物模研究     

童中山  应新亚  钱炳法 《海洋工程》1997,(4)

本文采用数值模拟与物模试验相结合的研究方法，详细地研究了黄骅电厂一、二、三期工程的取水特性。结果表明，现有河道只能满足电厂一期工程的取水需求；若将现有河道进行适当开挖，可以满足电厂三期取水需要。  相似文献   

Discussion on Coastal Erosion Near Xizhuang, Penglai, China   总被引：1，自引：0，他引：1  

Wu Guiqiu Li Wei Professor  First Institute of Oceanography  State Oceanic Administration  Qingdao Associate Researcher 《中国海洋工程》1994,(2)

-In this work, on the basis of the characteristics of coastal erosion near Xizhuang (Penglai, Shandong, China) and the in-situ measured data and theoretical calculation, the causes of coastal erosion there are obtained: (1) natural erosion, (2) beach sand borrowing, and (3) sand borrowing at the Dengzhou shoal near Xizhuang, which results in the loss of the function of the wave force resistance of the shoal. Since the wave energy is increased, the longshore sediment transport rate is increased. Coastal erosions are more and more serious. A scientific basis to reduced the calamity of coastal erosion in local area is presented. Some experiences are accumulated for studying coastal erosion.  相似文献   

东海西北部水团分析及与渔场的关系     

刘树勋  韩士鑫  魏永康 《中国海洋大学学报(自然科学版)》1989,(Z1)

作者用聚类分析法划分浅海水团,目的在于克服大洋水团分析法进行分析所遇到的一些困难,它在根据不同海区特点确定临界值与检验值时有较大的灵活性。本文讨论了浅海变性水团与中心渔场的关系。结果表明,东海底层冷水、东海表层水和大陆沿岸水对渔业生产有重要影响。  相似文献   

海洋走航式单边连续观测地震折射波Δt解释方法--1种新的浅层折射单支时距曲线解释方法     

薛荣俊  隋波  薛巍  张政民  田振兴 《中国海洋大学学报(自然科学版)》2004,34(2)

在浅层工程折射地震测量中 ,通常采用相遇观测系统采集数据和相应的解释方法进行解释 ;对于单边观测采集方法由于与其相应的解释方法较少而少被采用。本文提出 1种方法简单、精度可靠、可直接利用同一点相邻 2排列 2次观测的初至折射时间并适合于海洋走航式单边连续观测系统的折射初至资料解释方法。其精度基本与同观测段的采用相遇观测的差异时距方法解释的精度十分接近。该方法即适合于人工解释又适合于计算机自动解释。  相似文献   

琼州海峡铁路轮渡新海湾港区泥沙淤积问题     

沈莹  李大山  张镜潮  杨正己 《海洋工程》1997,(3)

海南省拟建琼州海峡铁路轮渡。本文通过对海峡南岸新海湾轮渡港址附近自然条件、岸滩演变和输沙特征的分析研究，对不同类型港区布置方案港内开挖区和航道的淤积强度、淤积量等进行了计算，并对不同防护建筑物的有效拦沙时间等进行了探讨和计算，提出了港区类型推荐方案。  相似文献   

中华绒螯蟹人工半咸水工厂化育苗试验研究报告   总被引：1，自引：0，他引：1  

刘连科  王洪芬 《海洋湖沼通报》1991,(3):80-83

在盐度为14—19‰的人工海水中,温度20—25℃条件下,189只平均体重100g的抱卵亲蟹产蚤状幼体4025万只。布苗密度为50—100万只/m~3为宜。必须经常换水,保持水质良好。人工饵料以单胞藻和丰年虫无节幼体为主,可适当加喂蛋黄。  相似文献   

On dynamic coupling effects between a spar and its mooring lines     

Xiaohong Chen  Jun Zhang  Wei Ma 《Ocean Engineering》2001,28(7):79

The responses of a spar constrained by slack mooring lines to steep ocean waves and tensions in the mooring lines are simulated using two different numerical schemes: a quasi-static approach (SMACOS) and a coupled dynamic approach (COUPLE). The two approaches are the same in computing wave loads on the structure. Their difference is in modeling dynamic forces of mooring lines; that is the dynamic forces are included in the computation of COUPLE but neglected in SMACOS. The numerical simulation is examined against the laboratory measurements of the JIP Spar in a water depth of 318 m. The dynamic coupling effects between the JIP Spar and its mooring lines in different water depths (318, 618 and 1018 m) are investigated by the comparison of numerical simulations obtained using the quasi-static and coupled dynamic approaches. It is found that the damping of mooring lines reduces the slow-drift surge and pitch of the Spar, especially in deep water. The reduction in the amplitude of slow-drift surge can reach about 10% in a water depth of 1018 m. The tension in mooring lines may greatly increase in the wave frequency range when dynamic forces in mooring lines are considered. The mooring-line tension in the wave frequency range predicted by the coupled dynamic approach can be eight times as great as the corresponding prediction by the quasi-static approach in a water depth of 1018 m. This finding may have important implications for the estimation of the fatigue strength and life span of the mooring lines deployed in deep water oceans.  相似文献