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Citation:
 Kunpeng Wang,Chunyan Ji.Helical Wire Stress Analysis of Unbonded Flexible Riser Under Irregular Response[J].Journal of Marine Science and Application,2017,(2):208-215.[doi:10.1007/s11804-017-1404-z]
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Helical Wire Stress Analysis of Unbonded Flexible Riser Under Irregular Response

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Title:
Helical Wire Stress Analysis of Unbonded Flexible Riser Under Irregular Response
Author(s):
Kunpeng Wang Chunyan Ji
Affilations:
Author(s):
Kunpeng Wang Chunyan Ji
School of Naval Architecture and Ocean Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, China
Keywords:
unbonded flexible riserinterlayer interactionhelical wire stresslocal flexurebending stiffness variationirregular response
分类号:
-
DOI:
10.1007/s11804-017-1404-z
Abstract:
A helical wire is a critical component of an unbonded flexible riser prone to fatigue failure. The helical wire has been the focus of much research work in recent years because of the complex multilayer construction of the flexible riser. The present study establishes an analytical model for the axisymmetric and bending analyses of an unbonded flexible riser. The interlayer contact under axisymmetric loads in this model is modeled by setting radial dummy springs between adjacent layers. The contact pressure is constant during the bending response and applied to determine the slipping friction force per unit helical wire. The model tracks the axial stress around the angular position at each time step to calculate the axial force gradient, then compares the axial force gradient with the slipping friction force to judge the helical wire slipping region, which would be applied to determine the bending stiffness for the next time step. The proposed model is verified against the experimental data in the literature. The bending moment-curvature relationship under irregular response is also qualitatively discussed. The stress at the critical point of the helical wire is investigated based on the model by considering the local flexure. The results indicate that the present model can well simulate the bending stiffness variation during irregular response, which has significant effect on the stress of helical wire.

References:

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Memo

Memo:
Received date:2016-11-29;Accepted date:2017-3-7。
Foundation item:Supported by the Natural Science Foundation of Jiangsu Province under Grant No. BK20160557, and the General Program for Colleges and Universities in Jiangsu Province under Grant No. 16KJD570001
Corresponding author:Kunpeng Wang, Email: wangkunpeng@just.edu.cn
Last Update: 2017-05-09