Experimental and Numerical Study on Holding Power of Rectangular-Shaped Anchors
Experimental and Numerical Study on Holding Power of Rectangular-Shaped Anchors
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DOI：
10.1115/omae2018-77814
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发表时间：
2018-06
期刊：
影响因子：
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通讯作者：
K. Toh;Yusuke Fukumoto;T. Yoshikawa
中科院分区：
文献类型：
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作者：
K. Toh;Yusuke Fukumoto;T. Yoshikawa
本文对矩形锚杆的锚固力进行了试验和数值研究。随着近海开发的推进，系泊系统常被用作海洋浮式结构物的位置保持系统。从能量消耗的角度来看，机械锚系泊系统优于动力锚系泊系统。然而，到目前为止，在深海区域，特别是超过500 m深度的区域，关于具有高保持锚的系泊系统的研究和开发在日本几乎没有进行。在大多数情况下，传统的锚形状已经通过实验和/或经验决定。此外，只有少数的研究与数值分析的实验测试已经进行了保持力。为了从理论上获得最佳的锚杆形状，因此，本研究的目的是发展的支持力的估计方法，并阐明锚在土壤中的渗透机制。本文利用小型锚模型进行了一系列试验。为了简化计算，本文采用矩形平板来模拟锚爪的形状。从改变锚模型的几何特征的几个实验中，获得了最大抓持力时抓持力、穿透深度和锚爪表面角的历史。此外，还进行了数值模拟，以评估持有权力的动态显式非线性有限元分析（NLFEA）代码，LS-DYNA，以及在内部的离散元法（DEM）代码。通过数值计算结果与实验结果的对比，验证了计算的准确性。
This paper discusses the experimental and numerical investigations for the holding power of rectangular-shaped anchors. As the offshore developments are promoted, the mooring systems are often used as the station keeping systems of the marine floating structures. From a viewpoint of the energy consumption, the mechanical mooring systems with anchors are better than the dynamic mooring systems with thrusters. Up to now, however, the research and development regarding the mooring systems with the high holding anchors in the deep sea area, especially more than 500 m in depth, have hardly been carried out in Japan. In most cases, the conventional anchor shapes have experimentally and/or empirically been decided. In addition, only a few studies which relate the numerical analysis to the experimental test have been performed for the holding power. In order to obtain the optimal shape of anchors theoretically, therefore, the purpose of this study is to develop the estimation method for the holding power and to clarify the penetration mechanism of anchors in soil. In this paper, a series of experiments utilizing the small-sized anchor model is conducted. Here, the fluke shape of specimen is modeled by the rectangular flat plate for simplicity. From several experiments varying the geometric characteristics of the anchor model, the experimental results, e.g., the history of the holding power, the penetration depth, and the fluke surface angle at the maximum holding power, are obtained. Furthermore, the numerical simulation to evaluate the holding power is also carried out using the dynamic explicit non-linear finite element analysis (NLFEA) code, LS-DYNA, as well as the in-house distinct element method (DEM) code. From the comparison between the numerical results and the experimental results, the calculation accuracy is verified.