scholarly journals Performance validation and dynamic response analysis of a deepwater cable bending restrictor

Author(s):  
Kang Yongtian ◽  
Xiao Wensheng ◽  
Zhang Dagang ◽  
Zhang Liang ◽  
Zhou Chouyao ◽  
...  

The deepwater cable bending restrictor is an important protective device for risers, umbilicals and cables in offshore engineering, protecting cable structure by controlling minimum bending radius. Its mechanical properties are analysed based on the numerical analysis model and finite element analysis (FEM) of ø175. The sensitivity analysis of using quantity of bending restrictors is also performed to show the effect of the quantity on bending stiffness. A testing scheme of bending stiffness of the bending restrictor is then formulated based on its structure. From numerical analysis results through test simulation, the tolerance is less than 3 %, which verifies the reliability of the numerical analysis model. Performance of the bending restrictor and dynamic response are analysed according to environmental parameters that occur once per 100 years from offshore wind power farms and pipein-pipe models, respectively. The results show the bending restrictor can effectively protect cable structure, and the pipein-pipe model is suitable for calculating mechanical properties of interaction between the bending restrictor and cable.

2019 ◽  
Vol 36 (3) ◽  
pp. 958-970 ◽  
Author(s):  
Zhi Ding ◽  
Danwei Li

PurposeThis paper aims to evaluate the dynamic response of surrounding foundation and study the vibration characteristics of track system.Design/methodology/approachA double-line underground coupling analysis model was established, which included two moving train, track, liner and the ground field.FindingsBased on the 2.5D (D is diameter) finite element analysis, the influence of the important factors such as the depth of the subway tunnel, the nature of the foundation soil, the relative position relation of the double tunnel, the subway driving speed on the foundation and the orbital vibration are analyzed in this article.Originality/valueThe results in paper may have reference value for the prediction of train induced vibrations and for the research of dynamic response of ground field.


Author(s):  
Hugh Martindale ◽  
Steven Rossiter ◽  
Terence Sheldrake ◽  
Richard Langdon

This paper presents improved dynamic modelling of subsea power cables using new models for the determination of non-linear cable mechanical properties. The modelling has been developed for cables typically used in offshore wind and for interconnectors, as well as dynamic power umbilicals. The results provide a better simulation of the dynamic response and allow better integration of local and global modelling for determination of stress and fatigue in offshore power cables. Cable response due to bending is modelled by including non-linear adhesion induced stresses due to a yielding bond between armour wire and neighbouring layers, which captures the effects of temperature and strain rate and provides better representation than purely friction-based modelling especially at low tension. Local armour bending stiffness is included by using average wire strain energy after slip along the strained helical path to determine the armour layer bending stiffness contribution. Mathematical modelling for mechanical properties is verified by sample testing and FEA, to provide a robust method for predicting cable response. Although dynamic subsea power cables are essentially non-bonded structures there is a certain amount of adhesion within the structure. Previous work has focused on friction-tension based modelling of armour wire-core interaction, that is not appropriate as critical slip curvatures at low tension are understated and full-slip stress distributions do not account for work done against friction during further bending. The principal result of this new approach is the improved determination of lifetime stresses for critical components within the cable structure. Non-linear bend stiffness modelling produces characteristic moment-curvature relations including hysteresis on reversal of bending. These curves provide an improved representation of the onset of slip in the armour wires and allow for the influence of temperature and strain rate on the cable bending stiffness to be included. The bend-stiffness model has been validated against test data both of complete bundles and individual components. The overall result is a methodology that typically results in increased fatigue life and can reduce the requirement for ancillary products such as ballast/buoyancy and bend stiffeners/restrictors. Additionally, the non-linear, hysteretic response of a cable significantly reduces certain phenomena that are often associated with numerical modelling of cables using a linear bend stiffness. Specifically, a cable catenary attached to a vessel and modelled with a linear bend stiffness will often experience ‘compression waves’ when the vessel is moving in response to wave loading. Use of a non-linear, hysteretic bend stiffness minimises the compression wave phenomenon, giving a much more realistic response and often greatly improving operability windows for offshore operations.


2012 ◽  
Vol 204-208 ◽  
pp. 1301-1306
Author(s):  
Guo Dong Zhang ◽  
Jian Long Zhang ◽  
Jian Long Cao ◽  
Wen Luo

Based on the theory of soil-structure interaction, the underground structure and surrounding soil as a system, and the finite element analysis model is established, and finite element dynamic analysis method is implemented, the three seismic acceleration time history of the different spectrum characteristics is inputted, the seismic effect on the surrounding ground of underground structure is analyzed. The results show that the effect on dynamic response is the limited range and not significant, when seismic design of structures on the surrounding sites is implemented, additional dynamic response on surrounding sites does not need to consider.


2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Xiaobin Hu ◽  
Chen Lu ◽  
Xiaoqing Zhu

This paper presents a simplified model for dynamic response analysis of the framed self-centering wall (FSCW) structure under seismic excitations. In the analysis model, the frame is equivalent as a single-degree-of-freedom system and collaborates with the self-centering (SC) wall to resist lateral loads. By way of pushover analysis of a typical FSCW structure, the proposed analysis model is validated by comparing the analysis results with those obtained from the finite element analysis method. Using the analysis model, motion equations of the FSCW structure under seismic excitations are established and solved through numerical simulations. Finally, a comprehensive parametric study is conducted to investigate the effects of a variety of design parameters on seismic responses of the FSCW structure. It shows that improving the yield force or elastic stiffness of the frame can help greatly lessen seismic responses of the FSCW structure in terms of the rotation angle of the SC wall.


Author(s):  
Makoto Tanabe ◽  
Hajime Wakui ◽  
Nobuyuki Matsumoto

Abstract A finite element formulation to solve the dynamic behavior of high-speed Shinkansen cars, rail, and bridge is given. A mechanical model to express the interaction between wheel and rail is described, in which the impact of the rail on the flange of wheel is also considered. The bridge is modeled by using various finite elements such as shell, beam, solid, spring, and mass. The equations of motions of bridge and Shinkansen cars are solved under the constitutive and constraint equations to express the interaction between rail and wheel. Numerical method based on a modal transformation to get the dynamic response effectively is discussed. A finite element program for the dynamic response analysis of Shinkansen cars, rail, and bridge at the high-speed running has been developed. Numerical examples are also demonstrated.


Author(s):  
Jingxia Yue ◽  
Weili Kang ◽  
Wengang Mao ◽  
Pengfei Chen ◽  
Xi Wang

Abstract Floating Storage and Regasification Unit (FSRU) becomes one of the most popular equipment in the industry for providing clean energy due to its technical, economic and environmental features. Under the combined loads from wind, wave and current, it is difficult for the prediction of the dynamic response for such FSRU-LNGC (Liquified Natural Gas Carrier) side-by-side mooring system, because of the complicated hydrodynamic interaction between the two floating bodies. In this paper, a non-dimensional damping parameter of the two floating bodies is obtained from a scaled model test. Then the numerical analysis is carried out based on the test results, and the damping lid method is applied to simulate the hydrodynamic interference between floating bodies. The dynamic response of the side-by-side mooring system including six degrees of freedom motion, cable tension and fender force are provided and analyzed. According to the comparisons between numerical results and the test results, it is shown that the proposed coupled analysis model is reliable, and the numerical analysis can properly describe the dynamic response of the multi-floating mooring system in the marine environment. Moreover, the non-dimensional damping parameter which is used in numerical analysis can act as a good reference to the dynamic response analysis of similar multi-floating mooring systems.


2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Yinhui Wang ◽  
Yidong Xu ◽  
Zheng Luo ◽  
Haijun Wu ◽  
Liangliang Yan

According to the flexural and torsional characteristics of curved thin-walled box girder with the effect of initial curvature, 7 basic displacements of curved box girder are determined. And then the strain-displacement calculation correlations were established. Under the curvilinear coordinate system, a three-noded curved girder finite element which has 7 degrees of freedom per node for the vibration characteristic and dynamic response analysis of curved box girder is constructed. The shape functions are used as the interpolation functions of variable curvature and variable height to accommodate to the variation of curvature and section height. A MATLAB numerical analysis program has been implemented.


2011 ◽  
Vol 378-379 ◽  
pp. 332-336
Author(s):  
Yong He Li ◽  
Ai Rong Liu ◽  
Qi Cai Yu ◽  
Pan Tang ◽  
Fang Jie Cheng

With an example of steel pipe concrete leaning-type arch bridge, space truss system Finite Element Analysis model is constructed using the Ruiz-Penzien random seismic vibration power spectrum model. The impact of inclined arch rib angle and the number of cross brace between main and stable arch ribs on the seismic internal force response under lateral random seismic excitation is also studied in this research. Research finding shows, the in-plane bending moment of main arch rib gradually increases with increasing stable arch rib angle and cross brace, whereas the out-of-plane bending moment and axial force display a decreasing trend. In general, this indicates that increasing stable arch rib angle and number of cross brace improves the lateral aseismatic performance of leaning-type arch bridge.


2012 ◽  
Vol 233 ◽  
pp. 224-227 ◽  
Author(s):  
Tao Yong Zhou ◽  
Bin Hu ◽  
Xue Jun Wang ◽  
Bo Yan

Railway ballast tamping operations is an important work in the line maintenance and repair operations, the selection of tamping parameter is usually dependent on field trials and practical experience, for the mechanical properties of railway ballast is difficult to measure and describe. This paper creates discrete element analysis model of railway ballast using the discrete element method, the numerical simulations are carried out to study the mechanical properties of railway ballast during tamping process. We focus on the influence of amplitude during tamping process; an optimal amplitude of the simulation analysis is obtained and compared with the recommended amplitude of Plasser & Theurer Company, it is found that the two amplitudes accord. This result verifies the correct validity of the discrete element analysis model of railway ballast during tamping process.


1989 ◽  
Vol 4 (1) ◽  
pp. 25-42 ◽  
Author(s):  
A.R. Kukreti ◽  
N.D. Uchil

In this paper an alternative method for dynamic response analysis of large space structures is presented, for which conventional finite element analysis would require excessive computer storage and computational time. Latticed structures in which the height is very small in comparison to its overall length and width are considered. The method is based on the assumption that the structure can be embedded in its continuum, in which any fiber can translate and rotate without deforming. An appropriate kinematically admissable series function is constructed to descrbe the deformation of the middle plane of this continuum. The unknown coefficients in this function are called the degree-of-freedom of the continuum, which is given the name “super element.” Transformation matrices are developed to express the equations of motion of the actual systems in terms of the degrees-of-freedom of the super element. Thus, by changing the number of terms in the assumed function, the degrees-of-freedom of the super element can be increased or decreased. The super element response results are transformed back to obtain the desired response results of the actual system. The method is demonstrated for a structure woven in the shape of an Archimedian spiral.


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