Structural Reliability of Broadside of a Bulk Carrier

The ultimate bending moment and maximal shear stress of a bulk carrier with two structural forms （single hull and double hull/ are calculated separately by using the combined moment which is determined by stochastic process. Then the assessment of reliability is carried out. The results indicate that by introducing the double-hull structure, the shear stress of side can be decreased to half of that of the primary structure（ 50.7% i. but the effect on longitudinal strength is not obvious. Finally, the effects of different double-side skin widths on ultimate bending moment and the maximal shear stress are investigated, followed by proposals of the selection of the double-side skin width.     

考虑畸变效应的梁单元刚度矩阵应用

基于势能驻值原理和广义坐标法原理推导出考虑截面畸变效应的梁单元刚度矩阵.根据此梁单元刚度矩阵,编制了计算薄壁钢箱梁结构的有限元程序,且此程序可以考虑截面畸变效应和扭转效应.运用自编程序,分析横隔板间距对薄壁钢箱梁受力性能的影响.通过数值计算,得出布置横隔板对畸变正应力的影响最大,对弯曲正应力的影响很小.畸变荷载作用下,只有当横隔板布置间距小到一定数值时,薄壁箱梁的畸变正应力才会减小.最后,引入畸变翘曲影响系数γ,简化了薄壁箱形梁纵向正应力的计算方法.当横隔板布置间距L与薄壁箱梁横截面最大尺寸H的比值小于2时,畸变翘曲影响系数γ趋于1,表明薄壁箱形梁的畸变正应力趋于零,可以忽略畸变效应的影响.     

无人商船运行体系研究

近年来,无人船艇在海洋勘探、海事搜寻救助、海洋测绘等领域得到了广泛应用,但无人商船运营和开展国际贸易时涉及法律主体、所载运货物保管、国际公约和船舶进出港安全等诸多因素,因此必须将无人船通信技术、船舶适航、货物保管、船员配备等环节形成完整体系,科学推进无人商船的运营,以达到“航运更安全、海洋更清洁”的目标。     

水动力导数的系统辨识

本文以伪随机二进制信号(PRBS)操舵,用同时测量轨迹与航向角的方法,计算得到漂角β,从而辨识了白箱模型(2.1),获得了操纵运动的水动力导数。并与PMM试验结果进行了比较,证实了本文方法的有效性。     

钢筋混凝土连续梁受弯承载力可靠性分析

由于钢筋混凝土连续梁的作用荷载、材料、几何特征等具有随机性,使其荷载效应、抗力也具有随机性。针对钢筋混凝土连续梁受弯承载力可靠性,采用Monte-Carlo （蒙特卡洛）法抽样进行计算,定性分析了荷载效应比、材料强度、楼面荷载类型等对钢筋混凝土连续梁受弯承载力可靠度指标的影响。研究结果表明：随荷载效应比增大,连续梁可靠指标减小;随材料强度增加,连续梁的可靠指标变化不明显;楼面活荷载类型对连续梁可靠指标有影响。     

无粘结部分预应力高强混凝土梁闭合弯矩计算

通过11根无粘结部分预应力高强混凝土梁，研究了影响裂缝闭合的主要因素；预应力筋配筋率、非预应力筋配筋率、跨高比、荷载作用方式，用无粘结配筋指标βpe和换算配筋率αpp这两个参数来反映对裂缝闭合弯矩的影响，应用名义拉应力建立了闭合弯矩计算公式；计算结果与试验结果吻合较好。     

论郑和宝船与册封舟--纪念郑和下西洋六百周年

从<明实录>中郑和第一次下西洋前夕有关造海船的记载、历史上福船在远洋航行和海战威力方面所居优势地位以及明初福建海防和造船业格局等诸方面分析,福船应是第一次下西洋的主要船型.而与郑和同时为中官、且在洪熙、宣德中曾四次奉敕出使琉球的柴山亦称自己所乘福船型册封舟为"宝船".由此可以认为,同为福船的宝船与册封舟只是一物二名而已.因此,我们将较可信的静海寺残碑和<前闻记>下西洋题本摘要中有关郑和船只的记载,与明朝后期册封琉球使臣们所撰<使琉球录>中关于册封舟形制的详细描述相结合并加以研究,相信有助于人们对郑和宝船获得符合客观实际的认识.     

Fatigue tests of composite beam by steel fiber reinforced self-stressing concrete in the hogging bending

Through the experiments of 7 T-section composite beams, steel fiber reinforced self-stressing concrete （SFRSC） as the composite beam in the composite layer was studied under the hogging bending. The tests simulated composite layer tensile strain under the hogging bending of inverted loading composite beams, giving the relationship under the different fatigue stress ratios between fatigue cycles and steel bar’s stress range, crack width, stiffness loss and damage, etc., in composite layer. This article established fatigue life equation, and analyzed SFRSC reinforced mechanism to crack width and stiffness loss. The results show that SFRSC as the composite beam concrete has excellent properties of crack resistance and tensile, can reinforce the fatigue crack width and stiffness loss of composite beams, and improve the durability and in normal use of composite beams in the hogging bending zone.     

简述船舶破损后采取应对措施及计算抗沉性方法

本文介绍了堵漏器材的种类,论述了船舶破损后应采取的各项应对措施,并且阐明了为保证船舶安全,正确计算船舶抗沉性两项方法。     

船舶性能实验教学系统

船舶性能实验教学系统是船舶性能实验课的导学、助学、自测及自检系统,它集基本理论、扩展知识、教学实验、数据采集、实验仿真和实船预报于一体,使得相关课程的教学及实验得到了强化和扩展。本系统运用VisualBasic程序设计语言,采用了面向对象的设计方法,结合可视化设计技术,使得该系统具有良好的可维护性、扩展性和开放性。     

EFFECT OF CORROSION ON BOND BEHAVIOR AND BENDING STRENGTH OF REINFORCED CONCRETE BEAMS

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压力传感器特性研究实验的ANSYS辅助教学

基于ANSYS的应力分析功能进行压力传感器特性研究,用ANSYS数值计算方法分析了压力传感器的弹性平行梁。数值计算结果表明,压力传感器的节点位移与压力之间存在线性关系,说明在一定范围内,输出电压与被测物体的重量成正比,和实验结果一致。计算机仿真手段能够得到直观弹性平行梁应力云图,更可以用动画生动的应力作用实验过程和结果。一定程度上弥补了实验教学手段的不足,展示普通实验无法完成的实验内容,还可以清楚地知道电阻应变片应该固定的具体位置。     

Analytical solution for functionally graded anisotropic cantilever beam under thermal and uniformly distributed load

The bending problem of a functionally graded anisotropic cantilever beam subjected to thermal and uniformly dis-tributed load is investigated,with material parameters being arbitrary functions of the thickness coordinate. The heat conduction problem is treated as a 1D problem through the thickness. Based on the elementary formulations for plane stress problem,the stress function is assumed to be in the form of polynomial of the longitudinal coordinate variable,from which the stresses can be derived. The stress function is then determined completely with the compatibility equation and boundary conditions. A practical example is presented to show the application of the method.     

异形阳台边梁设计的计算方法

从工程施工、设计中常见的质量问题分析入手,着重讨论了异形阳台边梁的受力性能,并提出了解决该问题的办法,即采用本人设计的钢筋砼受弯、剪、扭构件配筋实用计算程序。     

30米后张法预应力工字梁预制工艺及质量控制

钢绞线预应力混凝土在桥梁工程中已普遍使用,作为质量控制双控指标的钢绞线张拉伸长值及锚固张拉力的确定,是大梁张拉成功的关键。本文着重概述了预制大梁施工工艺及过程质量控制的主要环节,供从事钢绞线预应力张拉人员参考。     

小型民用船舶焊接常见缺陷及防治措施

产品质量是企业的生命,良好的船舶建造是保证船舶安全航行与作业的重要条件,小型民用船舶焊接是保证船舶致密性和强度的关键;详细介绍了船舶焊接中几种常见的焊接缺陷,分析了产生原因和危害,并提出防治措施。     

拱梁组合体系拱桥关键节点有限元分析

以某主跨85m钢管混凝土拱桥为研究对象,采用ANSYS建立局部精细化模型,对拱座进行受力分析。研究表明:拱梁组合体系拱桥拱座的结构刚度比较大,在拱脚最大弯矩工况下,最大变形出现在哑铃型拱肋加载截面下缘,变形值仅为4.3mm;拱座整体应力分析表明,结构受力以纵桥向受压为主,整体应力值不大,拱肋与拱座节点交界面因刚度突变出现了较大的应力变化,存在不大于1MPa的主拉应力;除了端横梁预应力锚固处压应力在10MPa左右,其他部位应力绝对值均在1MPa以下,满足要求;为了进一步优化结构受力,避免局部应力集中,应在结构中增加加腋、倒角等。     

船舶操纵运动方程系数的系统辨识

作者设计并制作了伪随机二进制(PRBS)信号发生器。并以PRBS信号操舵,辨识了船舶操纵运动方程的系数。用离散时间测量决定线性连续时间模型参数。给出了Mariner标准模型和一艘渔轮的辨识结果,并与标准的Nomoto K,T计算结果进行了比较,结果令人满意。     

智能仪表在直梁弯曲正应力实验中的应用

通过对材料力学直梁弯曲正应力实验的介绍,分析了所用三种测试仪器的特点,重点介绍了智能仪表在该实验中的应用,说明了智能仪表的应用使实验技术发生了巨大变革.     

Calculation Model of Equivalent Strength for Induced Crack Based on Double-K Fracture Theory and Its Optimizing Setting in RCC Arch Dam

By means of fracture testing on roller-compacted concrete (RCC) three-point bending beams with two different specimen sizes, the P-CMOD complete curve for RCC was gained. Furthermore, by applying double-K fracture theory, KIC^ini,KIC^un, as well as the critical effective crack length and the critical crack tip opening displacement, were evaluated. Based on the double-K fracture parameters above, the calculation model of equivalent strength for induced crack was established, thus the calculation method on its initiation, stable propagation and unstable fracture was ascertained. Moreover, the finite element simulation analysis of stress field in ShaPai arch dam and the on-site observational splaying points of induced crack at different altitudes validated the reliability of the model. Finally, crack inducer‘s optimal setting in RCC arch dam was studied. It improves the design level of induced crack in RCC arch dam and satisfies the necessity of engineering practice.