共查询到19条相似文献,搜索用时 187 毫秒
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精确评估模块柔性连接性能对连接器和超大型浮体的结构安全性具有重要意义,而模型试验是获取超大型浮体模块柔性连接性能的必要手段。文章以横向浮筒式的浅吃水超大型浮体为研究对象,根据连接器动响应计算结果,设计了柔性连接器模型;通过不同幅值和载荷组合的连接器静态拉伸和压缩试验,研究了超大型浮体连接器的刚度特性,探讨了组合载荷对连接器刚度的影响;通过不同幅值和周期的连接器纵向动态载荷试验,研究了超大型浮体连接器在动态载荷作用下的结构响应,验证了超大型浮体连接器结构的安全性和适用性。试验结果表明在静态和动态载荷作用下文中设计的柔性连接器连接可靠、结构安全,连接器载荷、位移和应力测量结果可为验证连接器结构设计和计算方法提供依据。 相似文献
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海上超大型浮式结构是由若干个与半潜平台相似的浮体通过连接器相连而成的一种新型海上结构,目前对其结构强度分析较少。文章基于直接计算方法,采用SESAM/Hydro D进行超大浮体单模块水动力分析并预报其波浪载荷,进而调用SESAM/Sestra模块进行超大浮体总体强度有限元分析。分析表明,超大浮体的三个连接部位出现了较大应力集中。选取这三处连接部位作为关键节点,采用ANSYS计算该三处关键节点的局部强度。研究结果表明,在横撑与下浮体连接处总体和局部应力均最大,该部位是易产生疲劳破坏的部位,需要重点研究。 相似文献
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超大型浮体结构在复杂海洋环境下承受多轴载荷共同作用,使得刚度较弱的撑杆结构极易发生破坏,从而影响整个浮体的安全和可靠性。文章以超大型浮体撑杆结构为研究对象,基于模型相似理论,进行了压扭联合载荷作用下撑杆结构极限强度试验模型设计,并开展模型试验研究。通过数值仿真方法与试验结果的对比分析,验证了数值仿真方法的正确性,并据此开展实尺度撑杆结构在不同扭转载荷作用下的压缩极限强度数值仿真计算,给出了压扭联合载荷作用下撑杆结构极限承载能力计算简化公式,为撑杆结构设计提供支撑。 相似文献
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为了降低VLFS(超大型浮体)模块连接的巨大载荷,通常选择柔性连接器.本文以某横向浮筒式的浅吃水超大型浮体为研究对象,采用RMFC模型(刚性模块柔性连接器)分析连接器载荷和模块运动响应,并与三模块模型试验进行比较验证.通过较高和较低横向刚度的系列纵向和垂向刚度组合的连接器载荷计算,给出连接器载荷随刚度变化的关系,分析连接器载荷峰值出现的原因.针对连接器载荷峰值对应的刚度组合,计算模块运动响应,分析模块相对运动模式.研究结果表明,对于较高和较低的横向刚度,均存在一定的纵向和垂向刚度组合,导致连接器载荷出现较大的峰值;连接器载荷峰值对应浪向角85°左右的海况,模块相对运动主要表现为艏摇. 相似文献
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《中国造船》2017,(2)
针对具有沙漏型浮式主体的新概念FDPSO,根据其浮体模型的特殊结构型式,论文提出了与之对应的有别于传统船舶和海洋平台的新型控制载荷工况。然后,采用基于频域波浪势流理论的边界元数值模拟方法研究了新型沙漏式浮体典型控制载荷的响应幅值算子。在此基础上,通过载荷长期极值预报方法,进行波浪搜索得到一系列设计波组。进一步,根据沙漏型浮体所受波浪载荷和运动RAO,分析了各个典型控制载荷峰值的成因。最后,基于准静态分析方法和浮体有限元模型,对最不利载荷工况下平台结构进行了强度分析,并结合HCSR规范对平台主体结构进行了强度校核,以期能够为新型沙漏式FDPSO的主浮体结构设计提供参考依据和准则。 相似文献
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The cross-section geometry of a submerged floating tunnel (SFT) has a large effect on hydrodynamic characteristics, structural behavior and service level, making the tunnel cross section the primary factor in optimizing efficiency. Minimizing the mean drag and the dynamic variability in the lift of the SFT cross section under bi-directional (i.e., tidal) flow has a dramatic impact on the reduction of structural displacements and mooring loads. Based on a parametric Bézier curve dynamically comprising the leading-edge radius, tunnel height and width to define the SFT geometry, a sensitivity analysis of the Bézier curve parameters for a fixed aspect ratio with prototype dimensions under uniform flow conditions was conducted by applying Computational Fluid Dynamics (CFD), and the pressure distribution around the SFT cross-section surface was analyzed. A theoretical method comprising the Kármán vortex street parameters was employed to verify the CFD simulation results. In order to determine the SFT cross section with optimal hydrodynamic properties, the mean drag and Root Mean Square (RMS) lift coefficients were selected as optimization objectives, and four Bézier curve parameters were the input variables, in a neural network and genetic algorithm optimization process (a hybrid BP-GA structure), which is less likely to become trapped in local minima. The results show the optimal tunnel cross section has a mean drag and a RMS lift coefficient reduced by 0.9% and 6.3%, respectively, compared to the original CFD dataset. 相似文献
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网格划分是水动力计算的关键环节,文中针对复杂形状海洋浮体提出了一种湿表面网格划分方法.对于有复杂首尾结构的浮体,用型线重构的方式在首尾生成曲面构成所需要的截面线,将通用建模工具和NURBS曲线拟合相结合,生成相贯结构的相交线;然后,用分片法生成浮体湿表面及内自由面网格,并独立表达各自的速度势以处理不规则频率现象,进而进行水动力系数计算.计算结果表明,上述处理方式很适合复杂形状海洋浮体水动力系数的计算. 相似文献
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XU Li ZHANG Min WANG Yan-ying 《船舶与海洋工程学报》2007,6(3):6-11
Mathematical models simulating steep waves at a focus point are presented in this paper. Simulations of extreme waves in a model basin were used to determine the loads on floating structures induced by the waves. Based on a new wave theory, numerical test results show that the simulation procedure is effective and the induced motion of water particles in the front of waves is an important factor influencing impact loads on floating bodies. 相似文献
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For the very large floating structure (VLFS) which is deployed near seashores, islands and reefs, the encounter wave conditions are always extremely complex. Traditional methods using homogeneous wave environment conditions cannot be applied for the analysis. In order to provide references for the further development of numerical methods, this paper reports an experimental study on responses of an 8-module VLFS under three different encounter wave conditions. The wave heights, accelerations, motions and connector loads of VLFS in three test schemes are obtained and analyzed. The comparative results show that the inhomogeneous wave conditions have an essential influence on the responses of VLFS. Especially for the connector loads, the values in the inhomogeneous wave conditions increase a lot compared with the other two test schemes. It indicates the traditional numerical methods using homogeneous wave field may not guarantee a safe design of VLFS and its connectors in the complicated wave environments. 相似文献
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《Marine Structures》2000,13(4-5):233-243
Loads acting on large floating structures usually consist of high-frequency and low-frequency loads. The high-frequency loads are associated with the hydroelastic behavior of the structure and excitation of the natural frequency modes. The low-frequency loads are associated with the body motion of the structure and the wave profile. In design analysis, extreme values of these loads must be combined taking into consideration the correlation between them. This paper discusses a methodology for combining the extreme loads, and proposes a simple formulation suitable for use in reliability analysis. A proposed load combination factor K was found to depend on the correlation coefficient of the two loads, the ratio of their standard deviations and the frequency content of the processes from which the loads are determined. The correlation coefficient was found to depend on the complex frequency response functions of the loads and the input wave spectrum. The paper also discusses characteristic extreme values of slightly nonlinear loads acting on large floating structures.Extreme loads may be based on a storm condition with a specified return period. Since very large floating structures are expected to have a long operational lifetime, the return period must be selected carefully. The paper discusses a method for selecting return periods based on the expected operational life of the structure and encounter probability. 相似文献
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深水半潜式钻井平台在码头舾装的周期较长,为确保安全,需对其码头系泊系统进行计算,以得到合理的系泊布置方式。以某深水半潜式钻井平台的码头系泊系统为例,进行风、流载荷共同作用下的抗台风系泊计算分析,建立了多浮体混合带缆系泊系统。 相似文献