Numerical Study on Mechanical Response of Steel Wire Wound Reinforced Rubber Flexible Pipe under Internal Pressure

2012 ◽  
Vol 594-597 ◽  
pp. 2668-2671
Author(s):  
Fan Gu ◽  
Hui Xin Wang ◽  
Li Sun

According to the actual structure of steel wire wound reinforced rubber flexible pipe, using the finite element software ANSYS, 3-D finite element model of flexible pipe is established. For the mechanical response of flexible pipe under internal pressure, the comparison on the result by numerical calculation, the static loading test and the result by analytic method shows that the 3-D finite element model of flexible pipe is rational. Moreover, based on the finite element model of flexible pipe, the influence of internal pressure, spanning length and reinforced steel wire diameter on the axial stress of the innerest steel layer and the Mises stress of the innerest rubber layer is analyzed.

2013 ◽  
Vol 671-674 ◽  
pp. 884-887
Author(s):  
Fan Gu ◽  
Hui Xin Wang ◽  
Dan Wang ◽  
Jia Quan Sun

According to the actual structure of submarine flexible pipe, considering the combined effect of internal pressure and transverse load by wave-current flow that is based on 50 year return period wave statistics data of Cheng Dao sea area, ANSYS finite element model of flexible pipe is established. The influence of internal pressure and suspension length on the axial stress of steel wire reinforcement layer and the Mises stress of rubber layer was analyzed. Comparatively, suspension is the main cause for the failure of steel submarine pipeline, but could hardly lead to the failure of submarine flexible pipe, which shows that flexible pipe is stronger applicable for submarine pipeline.


2012 ◽  
Vol 602-604 ◽  
pp. 2223-2226
Author(s):  
Fan Gu ◽  
Gan Song ◽  
Qiao Jin ◽  
Hui Xin Wang

According to the actual structure, using the finite element software ANSYS, numerical model of submarine oil flexible pipe was established. For the mechanical response of flexible pipe under the combined effect of internal pressure load and transverse load, the comparison on the result by numerical calculation and static loading test shows that the numerical model of flexible pipe is rational. Moreover, based on the numerical model of flexible pipe, this paper indicates that the maximum Mises stress occurs at the end of flexible pipe, which would lead to the bulge performance failure. Furthermore, the influence of winding angle on the mechanical properties of flexible pipe was analyzed, and the optimal winding angle 30° was suggested to adopt.


Author(s):  
José Renato M. de Sousa ◽  
Carlos Magluta ◽  
Ney Roitman ◽  
Tatiana V. Londoño ◽  
George C. Campello

In this work, the response of a 2.5″ flexible pipe to combined and pure axisymmetric loads is studied. A set of experimental tests was carried out and the results obtained are compared to those provided by a previously presented finite element model. The pipe was firstly subjected to pure tension. After that, the response to torsion superimposed with tension combined or not with internal pressure and the response to internal pressure combined with tension were investigated. In all these cases, the induced strains in the tensile armors were measured. Moreover, the axial elongation of the pipe was monitored in the pure tension test, whilst the twist of the pipe was measured when torsion was imposed and the axial reaction force was monitored when internal pressure was applied. The experimental results obtained agreed very well with the theoretical estimations indicating that the response of the pipe to tension and internal pressure is linear, whilst its response to torsion is nonlinear due to friction between layers.


Author(s):  
Luiz T. Souza ◽  
David W. Murray

The paper presents results for finite element analysis of full-sized girth-welded specimens of line pipe and compares these results with the behavior exhibited by test specimens subjected to constant axial force, internal pressure and monotonically increasing curvatures. Recommendations for the ‘best’ type of analytical finite element model are given. Comparisons between the behavior predicted analytically and the observed behavior of the experimental test specimens are made. The mechanism of wrinkling is explained and the evolution of the deformed configurations for different wrinkling modes is examined. It is concluded that the analytical tools now available are sufficiently reliable to predict the behavior of pipe in a manner that was not previously possible and that this should create a new era for the design and assessment of pipelines if the technology is properly exploited by industry.


Author(s):  
Arman Ahmadi ◽  
Narges Shayesteh Moghaddam ◽  
Mohammad Elahinia ◽  
Haluk E. Karaca ◽  
Reza Mirzaeifar

Selective laser melting (SLM) is an additive manufacturing technique in which complex parts can be fabricated directly by melting layers of powder from a CAD model. SLM has a wide range of application in biomedicine and other engineering areas and it has a series of advantages over traditional processing techniques. A large number of variables including laser power, scanning speed, scanning line spacing, layer thickness, material based input parameters, etc. have a considerable effect on SLM process materials. The interaction between these parameters is not completely studied. Limited studies on balling effect in SLM, densifications under different processing conditions, and laser re-melting, have been conducted that involved microstructural investigation. Grain boundaries are amongst the most important microstructural properties in polycrystalline materials with a significant effect on the fracture and plastic deformation. In SLM samples, in addition to the grain boundaries, the microstructure has another set of connecting surfaces between the melt pools. In this study, a computational framework is developed to model the mechanical response of SLM processed materials by considering both the grain boundaries and melt pool boundaries in the material. To this end, a 3D finite element model is developed to investigate the effect of various microstructural properties including the grains size, melt pools size, and pool connectivity on the macroscopic mechanical response of the SLM manufactured materials. A conventional microstructural model for studying polycrystalline materials is modified to incorporate the effect of connecting melt pools beside the grain boundaries. In this model, individual melt pools are approximated as overlapped cylinders each containing several grains and grain boundaries, which are modeled to be attached together by the cohesive zone method. This method has been used in modeling adhesives, bonded interfaces, gaskets, and rock fracture. A traction-separation description of the interface is used as the constitutive response of this model. Anisotropic elasticity and crystal plasticity are used as constitutive laws for the material inside the grains. For the experimental verification, stainless steel 316L flat dog bone samples are fabricated by SLM and tested in tension. During fabrication, the power of laser is constant, and the scan speed is changed to study the effect of fabrication parameters on the mechanical properties of the parts and to compare the result with the finite element model.


2012 ◽  
Vol 443-444 ◽  
pp. 751-756
Author(s):  
Li Jun Suo ◽  
Xia Guang Hu

In China, it is fact that porous concrete base has been used in the construction of asphalt pavement in recent years because porous concrete base has good performance. However, Reasonable design method has not been put forward so far. Therefore, it is necessary to analyze load stress and thermal stress of asphalt pavement which includes porous concrete base in order to put forward theoretical basis for pavement design method. In the paper, three–dimension finite element model of asphalt pavement, which includes porous concrete base and asphalt surface, is created for the purpose of studying load stress and thermal stress of porous concrete base in asphalt pavement. Based on numerical method of three–dimension finite element model, finite element software, such as ANSYS, is employed to study load stress and thermal stress of porous concrete base in asphalt pavement. After that, the effect of different factors on stress is studied, and the factors include thickness of surface, thickness of base and ratio of base’s modulus to foundation’s modulus. Finally, calculation results for stress are compared with each other, and it shows that load stress of porous concrete base decreases with increase of base’s thickness, while thermal stress of porous concrete base increases with increase of base’s thickness. Load stress and thermal stress of porous concrete base decrease with increase of surface’s thickness. Load stress and thermal stress of porous concrete base increase with increase of ratio of base’s modulus to foundation’s modulus.


Author(s):  
Michaël Martinez ◽  
Sébastien Montalvo

Abstract The mooring of floating platforms is an important challenge for the offshore industry. It is an important part of the design engineering and, often, a critical point for the fatigue life assessment. A solution that could improve the fatigue life is to directly connect the mooring rope to the platform, without an intermediate chain. However this solution is not widespread and the behavior of a rope near such a connection is little known. The present paper proposes to better understand this behavior, thanks to a detailed finite element model of the rope. The study case is a steel wire rope directly connected to a floating wind turbine. A local finite element model of the rope has been built, where the wires are individually modeled with beam elements. One end of the rope is clamped, simulating the connection, while tension and cyclic bending oscillations are applied to the other end. A localized bending takes place near the connection, leading to stress concentration in the wires. The stress concentration and the local contact forces are calculated for each wire. These data are important entry parameters for a local failure or fatigue analysis. This latter is however not presented here. Despite IFPEN experience in the development of local finite element models of steel wire ropes, it is the first time that such a high capacity rope (MBL = 12 500 kN) is modeled. This is challenging because of the large diameter of the rope and the large number of wires. However this modeling approach is very valuable for such ropes, because the experimental tests are rare and very expensive.


Author(s):  
Guopeng Ren ◽  
Rong Pan ◽  
Feng Sun

Reactor containment of a nuclear power plant is a structure to ensure the safety of nuclear power plant. It acts as the last barrier to prevent the release of radioactive materials from NPP during accidents. Finite element models were established to simulate a 1/3 scale model of a reactor containment building under leakage test pressure. General finite element software ANSYS were applied. The nonlinear behavior of containment materials, geometric were taken into account in the analysis. The reliability of the finite element model was verified through the comparison of theoretical analysis results with experimental results. In the ANSYS finite element model, the concrete, steel bars and prestress tendons were separated and the prestress tendons were considered by the method of cooling method on the prestress tendon elements. The mechanical properties of the finite element model in the prestress tension process and the absolute internal pressure of 0.52MPa were analyzed. Transient and time dependent losses were taken into account at the same time during the calculation of prestress of tendons, so as to calculate effective prestress at different locations of tendons. Calculation results of prestress losses show that the prestress losses at the hole of equipment hatch are larger than the other areas. The results show that, the deformation of over-all structure of the containment is shrink inward under the action of prestress. And the simulation can achieve the consistent deformation effect between tendons and concrete. The maximum radial displacement of the whole containment structure is located at of 10 ° ∼ 20 °area on the right of the hole of the gate. The effect of expansion deformation of the containment caused by design internal pressure is insufficient to offset the inward shrink effect generated by tendons, and the over-all structure of the concrete containment scale model is mainly under compressive stress. The containment test model is still with a large safety margin under the action of design internal pressure. The largest tensile stress is on the up and down areas of the internal sides of the equipment hatch, dome area close to ring beam, and bottom of perimeter wall close to the base slab. There is possibility of cracking on the concrete in limited local zones. This benchmark can provide a reference for engineering design of containment.


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