Stability analyses of steel pipe in pipe-jacking and the optimization of wall thickness

2011 ◽  
Author(s):  
Zhi-feng Zhao ◽  
Guang-hui Shao
Keyword(s):  
Wall Thickness ◽  
Steel Pipe ◽  
Stability Analyses ◽  
Pipe Jacking

Deflection behavior of the steel pipe-jacking in soft soil seabed

2014 ◽  
pp. 105-110
Author(s):  
L Zhen ◽  
J Chen ◽  
J Wang ◽  
G Cheng ◽  
Q Li
Keyword(s):  
Soft Soil ◽  
Steel Pipe ◽  
Pipe Jacking

Research on Brittle Fracture of X70/X80 Line Pipes with Big Wall Thickness at Low Temperature

2019 ◽  
Vol 795 ◽  
pp. 3-8
Author(s):  
Hai Tao Wang ◽  
Shi Li Li ◽  
Yan Long Luo ◽  
Jun Qiang Wang ◽  
Hai Bin Zhang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Brittle Fracture ◽  
Wall Thickness ◽  
Impact Energy ◽  
Charpy Impact ◽  
High Rate ◽  
Steel Pipe ◽  
Thickness Effect ◽  
Structural Factors ◽  
Charpy Impact Energy

Based on research of the low temperature fracture property of high grade steel pipe, it shows that X70, X80 steel pipe and X80 tee have high Charpy impact toughness. However, as the wall thickness increases, the shear area of DWTT decreases rapidly, and the thickness effect is significant. The research results show that the original wall thickness impact specimen fracture of steel pipe may not be ductile, for design temperature less than -30°C and wall thickness greater than 40mm. The brittle fracture was caused by structural factors. The Charpy impact energy, which just reflects the toughness of materials, does not show the fracture appearance as it would occur in service, because of the different specimen geometry and high rate of impact. The brittle fracture can occur at low temperature and low stress even with a high Charpy impact energy, the conditions of brittle fracture should be established under combination of the wall thickness, temperature and other factors. In this work, it is clarified that measurement of the fracture toughness under service temperature should be used to control low stress brittle fracture, besides the Charpy impact energy to ensure the material toughness.

Experimental and finite element study on the single-layer reticulated composite joints

2020 ◽  
Vol 23 (10) ◽  
pp. 2174-2187
Author(s):  
Liang Zheng ◽  
Cheng Qin ◽  
Hong Guo ◽  
Dapeng Zhang ◽  
Mingtan Zhou ◽  
...  
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Axial Compression ◽  
Wall Thickness ◽  
Great Influence ◽  
Single Layer ◽  
Experimental Results ◽  
Steel Pipe ◽  
Cover Plate ◽  
Element Analysis

In this article, a new type of reticulated joint, named the steel–concrete composite reticulated shell joint, is proposed. The proposed reticulated shell joint consists of an inner circular steel pipe, an outer circular steel pipe, a steel cover plate, and internal concrete. Five test specimens were tested under axial compression. The variable study included the wall thickness of the inner and outer circular steel pipes and the radius of the inner circular steel pipe. The test specimens exhibited a high bearing capacity and good plastic deformation ability under axial compression. The test results show that the wall thickness of the outer circular steel pipe and the radius of the inner circular steel pipe have a great influence on the bearing capacity of the steel–concrete composite reticulated shell joint, while the wall thickness of the inner circular steel pipe has little influence on the bearing capacity of the steel–concrete composite reticulated shell joint. Based on the test of the steel–concrete composite reticulated shell joints under axial load, the three-dimensional nonlinear finite element model was used to analyze the mechanical properties of the steel–concrete composite reticulated shell joints under axial compression. The results of the finite element analysis showed good agreement with the experimental results. The formula for calculating the bearing capacity of the joint is derived. By comparing with the experimental results, the calculated results are basically consistent with the experimental results.

Finite Element Modeling of the Dynamic Response of a Steel Pipe During Water Hammer

2012 ◽  
Author(s):  
Juan C. Suárez ◽  
Paz Pinilla ◽  
Javier Alonso
Keyword(s):  
Finite Element ◽  
Wall Thickness ◽  
Pipe Wall ◽  
Element Model ◽  
Water Hammer ◽  
Steel Pipe ◽  
Dynamic Stresses ◽  
Rate Dependent ◽  
Simple Step ◽  
Von Mises

Water hammer imposes a steep rise in pipe pressure due to the rapid closure of a valve or a pump shutdown. Transversal strain waves propagate along the pipe wall at sonic velocities, and dynamic stresses are developed in the material, which can interact with discontinuities and contribute to an unexpected failure. Pressure increase has been modeled as a simple step front in a finite element model of a short section of a steel pipe. Boundary conditions have been considered to closely resemble the conditions of longer pipe behavior. The shock traveling along the length of the fluid-filled pipe causes a vibration response in the pipe wall. Dynamic strains and stresses follow the water hammer event with a certain delay, as is shown from the results of the FEA. Response of the material is strain rate dependent and dynamic peak stresses are substantially larger than the expected from the static pressure loads. Damping of the waves, neither by the material of the pipe nor by the interaction fluid-pipe, has not been considered in this simple model. Hoop, axial, radial, and Von Mises equivalent stresses have been evaluated both for the overshooting and the following phase of decompression of a pipe without discontinuities. However, dynamic stresses can be enhanced in the presence of discontinuities such as laminations, thickness losses in the pipe wall due to corrosion, changes in the wall thickness in neighboring pipe sections, dents, etc. These dynamic effects are able to explain how certain discontinuities that were reported as passing an Engineering Critical Assessment can eventually cause failure to the integrity of the structure. Deflections in the pipe wall can be altered by the welded transition from a pipe with a certain thickness to another with a smaller thickness, and wavelength changes of one order of magnitude can be expected. This can result in different approaches towards the risk assessment for discontinuities in the proximity of changes in wall thickness.

Strengthening Effect From Steel Pipe Cladding in Pure Bending

2006 ◽  
Author(s):  
Ha˚var Ilstad ◽  
Hroar A. Nes ◽  
Geir Endal
Keyword(s):  
Carbon Steel ◽  
Wall Thickness ◽  
Local Buckling ◽  
Defect Size ◽  
Steel Pipe ◽  
Strengthening Effect ◽  
Pure Bending ◽  
Internal Corrosion ◽  
Corrosion Resistant Alloy ◽  
Clad Steel

Clad steel pipelines consist of a typically 3 mm thick internal corrosion resistant alloy with metallurgical bonding to the outer carbon steel pipe. The method of clad pipe manufacture gives intrinsic rise to disbonded areas (defects) in between the two materials, and there is concern that such disbondment defects may trigger local buckling of the cladding when the pipe is subject to severe bending, e.g. when installed by the reeling method. This paper addresses the possibilities for local buckling of the cladding material with the steel pipe in pure bending. Disbonded areas are studied numerically, and the critical defect size regarding local buckling of the cladding is established and compared with the allowable defect size as defined in the manufacture specification. It is shown that allowable disbondment defects of 500 mm2 are only 1/20 of the necessary area for local buckling during installation by the reeling method. In traditional pipeline design, the possible strengthening effect from the cladding on a steel pipe is not taken into account. In this paper, the strengthening effect from the cladding with the pipe in pure bending is studied. For the pipeline analysed it is shown that the deformation controlled local buckling resistance of the clad steel pipe is at least equivalent to a full thickness carbon steel cross-section. Hence, for a clad steel pipeline installed by the reeling method, the required wall thickness can be calculated by assuming the total wall thickness to be solid carbon steel.

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