Coupled BEM-FEM Analysis of the Large-Diameter Cylinder Structure System

A method of coupled BEM-FEM analysis for the elastic spatial structure system is presented. It can be applied to the calculation of the stress and deformation of the large-diamater cylinder structure system and it is suitable for symmetric or non-symmetric structures under the distributed or concentrated load. Numerical examples show that the proposed method and computer program BEFEM are quite efficient in the analysis of the large-diameter cylinder structure problems in ocean engineering.

Dynamic Wave Pressures on Deeply Embedded Large Cylindrical Structures due to Random Waves

The response of dynamic wave pressures on structures would be more complicated and bring about new phenomena under the dynamic interaction between soil and structure. In order to better understand the response characteristics on deeply embedded large cylindrical structures under random waves, and accordingly to offer valuable findings for engineering, the authors designed wave flume experiments to investigate comparatively dynamic wave pressures on a single and on continuous cylinders with two different embedment depths in response to two wave spectra.The time histories of the water surface elevation and the corresponding dynamic wave pressures exerted on the cylinder were analyzed in the frequency domain. By calculating the transfer function and spectral density for dynamic wave pressures along the height and around the circumference of the cylinder, experimental results of the single cylinder were compared with the theoretical results based on the linear diffraction theory, and detailed comparisons were also carried out between the single and continuous cylinders. Some new findings and the corresponding analysis are reported in present paper. The investigation on continuous cylinders will be used in particular for reference in engineering applications because information is scarce on studying such kind of problem both analytically and experimentally.

沉入式大直径圆筒码头稳定性计算方法研究

以工程应用为原则 ,研究沉入式大直径圆筒码头的分类及相应的设计理论与计算方法。根据大直径圆筒码头的工作原理 ,提出了大直径圆筒桩墙式码头的新概念 ,以及将沉入式大直径圆筒码头划分为大直径圆筒重力式码头和大直径圆筒桩墙式码头两种结构类型。建立了大直径圆筒桩墙式码头的稳定性计算方法。对于大直径圆筒重力式码头的稳定性验算 ,建议采用重力式码头的计算思路 ,但要合理考虑筒内外土体对结构稳定性的作用。通过数值计算 ,研究了结构特征参数对大直径圆筒桩墙式码头稳定性的影响。

大圆筒岸壁码头的量纲分析和离心模拟(英文)

认识土与沉入式无底大直径圆筒结构岸壁码头之间相互作用机制,对于它的安全和经济设计至关重要。基于量纲分析,首先研究确定了控制这种岸壁码头性状的无量纲项,然后,为研究这些无量纲项的相对重要性,设计了模型试验,并对试验结果分析解释。在所完成的离心模型试验中,就岸壁码头变形机制进行了观察,发现圆筒岸壁上部是偏离墙后土体向海侧倾斜,同时码头后场表面有沉降发生。离心试验结果的多元回归分析发现,圆筒岸壁的相对侧向位移对筒体前侧嵌入泥面以下的埋深比最为敏感,而侧向位移对圆筒的径高比的灵敏度不足前一因素的50%。相对来说,所测得的位移和土压力对筒壁的摩擦不很灵敏。对土压力结果的分析表明,作用于圆筒岸壁的侧向土压力可依据朗肯主动土压力理论,根据筒后土体的不排水强度进行预测。

软土地基中插入式大直径薄壁圆筒结构的一种简化数值计算方法

简述了对插入式大直径薄壁圆筒进行数值分析采用的力学机制,用弹簧元模拟薄壁圆筒与地基土体接触面间的连接所形成一种简化的数值计算模型,运用大型通用有限元软件ANSYS进行二次开发后对其进行数值计算与分析,比较了对筒内外淤泥粘土采用不同加固处理方法以及考虑相邻圆筒间采用不同边界约束条件时,对圆筒的应力和稳定性的影响。通过实例计算,验证了该数值模型的有效性与可行性,并得出一些有益结论。

深埋式薄壁圆筒结构在滩海地基中的受力特性数值模拟

建立三维有限元模型,分析深埋式薄壁圆筒结构在施工工况和使用工况下的结构变形位移、内力分布、基底应力分布、结构-土体间土压力分布,并对比分析了有限元计算结果及规范法计算结果。结果表明,有限元法计算出来的土压力中下段分布呈现"凸肚子"形状,与结构实际受力状态更加接近,有限元计算边界点沉降小于中心点沉降,与分层总和法的计算结果基本一致。

插入式大圆筒岸壁结构设计的新思路

通过对几个已建工程的回顾,归纳了我国插入式大圆筒岸壁水工建筑物通常的设计思路,并结合前苏联(俄罗斯联邦)、日本、英国等国家的相关结构设计规范或标准以及格型钢板桩(管)岸壁结构的设计思路或计算方法,对插入式大圆筒岸壁结构的使用条件、设计思路进行了统计归纳和对比分析。在总结现有设计与施工技术经验的基础上,提出了插入式大圆筒岸壁结构的使用条件和结构设计的新思路,希望起到抛砖引玉之作用。

嵌入式风缸盖工艺与模具设计

分析了嵌入式风缸盖的工艺特点,确定了最终的加工工艺,介绍了拉深模和落料模的设计思路、模具结构特点。生产证明,嵌入式风缸盖的制作工艺可行,拉深模和落料模设计合理,取得了较好的效果。