Water entry of a bow-flare ship section with roll angle

The two-dimensional water entry of a bow-flare ship section with constant roll angle, or heel angle, was studied by using a boundary element method. The fully nonlinear free surface conditions and exact body boundary conditions were satisfied. Nonviscous flow separation from the knuckles of the section or from the curved bottom could be simulated. The numerical calculations were compared with existing experimental results. First, the effects of roll angle were investigated and then the characteristics associated with large roll angles were examined in particular. The evolution of the free surfaces and the pressure distributions on the section surface are illustrated and the influence of nonviscous flow separation from the leeward section surface is discussed.     

船体分段制造最低成本的二次规划模型及其求解

以分段建造费用与工时成线性关系为前提建立的船体分段制造最低成本数学模型其约束条件呈线性关系,目标函数边际收益递减,将最低成本模型改进为二次规划,利用EXCEL工具进行求解,实例计算逼近全局最优,方法简单实用.     

新型缓粘结预应力体系的试验研究

介绍了一种以树脂胶粘剂为介质的新型缓粘结预应力体系的试验研究,其中包括能满足该体系要求的固化期在3、6、12个月左右、抗压强度50 MPa以上的胶粘剂组分及物理力学性能的研究;对预应力筋在不同时间张拉锚固作业中的κ和μ进行测量;缓粘结预应力筋在应力状态下进行了腐蚀试验;采用缓粘结预应力筋制作了8根预应力受弯构件进行试验,并与同条件制作的有粘结、无粘结预应力梁进行比较。结果表明,胶粘剂固化后的缓粘结预应力构件的工作性能,几乎和有粘结预应力构件相同。通过几个缓粘结预应力工程的施工,表明该体系的施工工艺与无粘结预应力施工工艺相近,简便易行。该体系将后张法中的无粘结和有粘结预应力混凝土体系相结合,使传统的预应力技术有了更新的发展。     

京福高速公路徐州绕城西段煤矿采空区处治研究

京福高速公路徐州绕城西段穿越徐州市北部和西部,要通过富水倾斜的复杂煤矿采空区,经过采用注浆立填法进行处治取得了成功,可为今后类似复杂采空区处理的勘察设计和治理工程提供技术借鉴和指导作用。     

超大断面公路隧道浅埋段施工技术

随着公路建设规模日益扩大,3车道、4车道的超大断面公路隧道越来越多。隧道浅埋段覆盖层薄、围岩稳定性差,开挖时易出现坍塌等工程事故,是超大断面隧道施工技术的重点和难点。结合深圳盐排高速公路盐田隧道的施工实践,介绍浅埋段施工的一些经验和技术体会,可为类似工程施工提供参考。     

不锈钢圆管内湍流摩擦因数研究

针对不锈钢圆管湍流摩擦因数计算存在的问题,在雷诺数为(1～15)×104的范围内,测定了不锈钢圆管的阻力性能,并对其湍流摩擦因数进行计算和分析,在此基础上提出了计算该种不锈钢圆管湍流摩擦因数的经验公式,并与常用的计算光滑圆管湍流摩擦因数的经验公式进行比较.结果表明,提出的经验式计算值与实测值基本一致,平均误差0.606...     

互通立交匝道端部纵断面设计探讨

匝道纵断面设计是互通立交设计中的重要一环,尤其是位于匝道起终点端部处的设计高程及设计坡度的计算更是其中一大难点.笔者根据多年设计经验,结合现有规范,对这一难点进行分析,并提出一种新的设计思路以供参考.     

Structural response of a flexible pipe with damaged tensile armor wires under pure tension

This article studies the structural response of a 6.0” flexible pipe under pure tension considering intact and damaged conditions. In the damaged condition, several wires of the tensile armor layers are assumed to be broken. A three-dimensional nonlinear finite element (FE) model devoted to analyze the local mechanical response of flexible pipes is employed in this study. This model is capable of representing each tensile armor wire and, therefore, localized defects, including total rupture, may be adequately represented. Results from experimental tests validate the FE predictions and indicate a reduction in the axial stiffness of the pipe, a non-uniform redistribution of forces among the remaining intact wires of the damaged tensile armor layers and high stress concentrations in the wires near the broken ones. Moreover, the FE model indicates that significant normal bending stresses may arise in the pressure armor and inner carcass due to an uneven pressure distribution on these layers. Finally, the results obtained are employed to estimate the pull out capacity of the studied flexible pipe.     

整体表面淬火强化的铸钢摩擦楔

对货车转向架减振部件铸钢摩擦楔的使用寿命和耐磨性进行了研究,建议采用整体表面淬火工艺提高寿命。     

丰南至古冶段改建工程设计研究

205国道丰南-古冶段旧路部分路段在唐山市区穿过,造成严重的交通干扰,事故频繁发生.为彻底改善205国道的交通状况,将205国道改线到中心城区外围,旧路作为城市道路使用,既保证了城市交通发展又为过境车辆提供快速、便捷通道.