Numerical Study on Torsional Behavior of Carbon Steel-Concrete-Stainless Steel Double-Skin Tube (DST)

2020 ◽  
Author(s):  
Fa-Cheng Wang ◽  
Wen-Qi Xie ◽  
Lin-Hai Han
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Carbon Steel ◽  
Finite Element Model ◽  
Interaction Model ◽  
Element Model ◽  
Cohesive Force ◽  
Internal Corrosion ◽  
Double Skin ◽  
Skin Tube

Abstract One type of submarine composite pipeline structure, with carbon steel-concrete-stainless steel (CCS) double-skin tube (DST), was introduced in this paper. This composite pipeline was expected to make optimal use of the three types of the materials, and provide significant structural and internal corrosion resistance. During installation and service stage, submarine pipelines may experience significant torsion effects. Global response of the system depends on both the behavior of each constituent part and interactions between them. In this paper, an interaction model considering the friction and the cohesive force between the steel tube and the concrete is introduced, and a finite element model of the submarine pipeline under torsion is established by using this interaction model. The developed finite element model was verified through the comparisons between the numerical and experimental determined results, in terms of torque rotation angle histories, stiffness and ultimate torque. The results show that the ultimate strength and stiffness of the model considering cohesive force are increased by 4.6% and 11.9% respectively compared with the model only considering friction force.

Finite Element Modeling of Selective Laser Melting 316L Stainless Steel Parts for Evaluating the Mechanical Properties

2016 ◽  
Author(s):  
Arman Ahmadi ◽  
Narges Shayesteh Moghaddam ◽  
Mohammad Elahinia ◽  
Haluk E. Karaca ◽  
Reza Mirzaeifar
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Stainless Steel ◽  
Finite Element Model ◽  
Grain Boundaries ◽  
Mechanical Response ◽  
Element Model ◽  
Polycrystalline Materials ◽  
Microstructural Properties ◽  
Laser Melting

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.

scholarly journals Hydrogen Effects on the Burst Properties of Type 304L Stainless Steel Flawed Vessels

2008 ◽  
Author(s):  
Michael J. Morgan ◽  
Monica C. Hall ◽  
Poh-Sang Lam ◽  
W. Dean Thompson
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Finite Element Model ◽  
Element Model ◽  
Burst Pressure ◽  
304L Stainless Steel ◽  
Helium Gas ◽  
Lower Volume ◽  
Hydrogen Deuterium ◽  
Deuterium Gas

The effects of hydrogen and burst media on the burst properties of Type 304L stainless steel vessels were investigated. The purpose of the study was to compare the burst properties of hydrogen-charged stainless steel vessels burst with different media: water, helium gas, and deuterium gas. A second purpose was to provide data to improve an existing finite-element model for predicting burst behavior. Burst tests were conducted on hydrogen-charged and uncharged axially-flawed cylindrical vessels. The results indicate that samples burst pneumatically had lower volume ductility than those tested hydraulically. For pneumatic burst tests, samples burst with deuterium gas had slightly lower ductility than helium gas tests. For uncharged samples, burst pressure was not affected by burst media. For samples pre-charged with hydrogen, deuterium burst pressures were about 80% of the hydraulic or helium burst pressures. Hydrogen-charged samples had lower volume ductility and slightly higher burst pressures than uncharged samples. The results of the tests were used to verify and improve a previously developed predictive finite-element model. The existing finite-element model can qualitatively predict the expected changes in burst properties with hydrogen or tritium service, but a better material property database is required for quantitative predictions.

scholarly journals Numerical analysis of concrete-filled spiral welded stainless steel tubes subjected to compression

2018 ◽  
Author(s):  
Dongxu Li ◽  
Brian Uy ◽  
Farhad Aslani ◽  
Chao Hou
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Finite Element Model ◽  
Mechanical Performance ◽  
Load Capacity ◽  
Element Model ◽  
Experimental Program ◽  
Design Parameters ◽  
Steel Tubes ◽  
Finite Element Software

Spiral welded stainless tubes are produced by helical welding of a continuous strip of stainless steel. Recently, concrete-filled spiral welded stainless steel tubes have found increasing application in the construction industry due to their ease of fabrication and aesthetic appeal. However, an in-depth understanding of the behaviour of this type of structure is still needed due to the lack of proper design guidance and insufficient experimental verification. In this paper, the mechanical performance of concrete-filled spiral welded stainless steel tubes will be numerically investigated with a commercial finite element software package, through which an experimental program can be designed properly. Specifically, the proposed finite element models take into account the effects of material and geometric nonlinearities. Moreover, the initial imperfections of stainless steel tubes and the form of helical welding will be appropriately included. Enhancement of the understanding of the analysis results can be achieved by extending results through a series of parametric studies based on the developed finite element model. Thus, the effects of various design parameters will be further evaluated by using the developed finite element model. Furthermore, for the purposes of wide application of such types of structure, the accuracy of the behaviour prediction in terms of ultimate strength based on current design codes will be studied. The authors herein compared the load capacity between the finite element analysis results and the existing codes of practice.

scholarly journals Equivalent SPS Compact Double Hull (CDH) Bottom Structure Grounding of Inland Waterway Barges

2018 ◽  
Vol 12 (23) ◽  
pp. 41
Author(s):  
Stephen J. Kennedy ◽  
Aldo E. Martino ◽  
Alireza Mirzaei ◽  
Fabio Zapata
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Simulation Study ◽  
Oil Pollution ◽  
Element Model ◽  
Superior Performance ◽  
Alternative Method ◽  
Inland Waterway ◽  
Double Skin ◽  
Double Hull

MARPOL regulations stipulate that all single hull oil carrying barges must be made of double skin construction or modified by an alternate construction provided that the construction ensures at least the same level of protection against oil pollution.  It is be demonstrated that the proposed alternative method of design, made with a SPS Compact Double Hull (CDH) applied to the bottom hull, does not rupture under the prescribed grounding event (no rupture, no oil outflow, no oil pollution). A sophisticated finite element model was developed to simulate the grounding event for a single hull barge.  Based on the experience gained from this simulation, a comparative grounding simulation study was conducted where a specified embedded object causes rupture of the outer and inner hull for double hull construction (a non-zero probability of oil outflow and pollution) and no rupture of the SPS CDH which demonstrates superior performance.

scholarly journals Thermo-Mechanical Analysis on Thermal Deformation of Thin Stainless Steel in Laser Micro-Welding

2016 ◽  
Vol 6 (2) ◽  
pp. 51-66 ◽  
Author(s):  
Mohd Idris Shah Ismail ◽  
Yasuhiro Okamoto ◽  
Akira Okada
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Finite Element Model ◽  
High Speed ◽  
Continuous Wave ◽  
Element Model ◽  
Scanning System ◽  
Welding Deformation ◽  
Scanning Velocity ◽  
Stress And Deformation

In the present study, a three-dimensional finite element model has been developed to simulate the temperature, stress and deformation fields in continuous wave (CW) laser micro-welding of thin stainless steel sheet. The welding deformation was experimentally evaluated using a single-mode fiber laser with a high-speed scanning system. Application of developed thermal model demonstrated that the laser parameters, such as laser power, scanning velocity and spot diameter have a significant effect on temperature field and the weld pool. In the case of welding deformation, numerical simulation was carried out by an uncoupled thermo-mechanical model. The welding stress and deformation are generated by plastic deformation during the heating and cooling periods. It was confirmed that the residual stress is higher than yield strength and has strongest effect upon the welding deformation. The numerical simulated results have proved that the developed finite element model is effective to predict thermal histories, thermally induced stresses and welding deformations in the thin material.

A Finite Element Model for Simulating Out-of-Plane Behavior of Masonry Infilled RC Frames

2012 ◽  
Vol 166-169 ◽  
pp. 849-852 ◽  
Author(s):  
Chang Hai Zhai ◽  
Jing Chang Kong ◽  
Xiao Hu Wang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Interaction Model ◽  
Material Model ◽  
Element Model ◽  
Plane Failure ◽  
Rc Frames ◽  
Out Of Plane ◽  
Infilled Rc Frames ◽  
Masonry Infilled Rc Frames

The in-plane seismic performance has been studied by many researchers all over the world, whereas few studies have been done on the out-of-plane behavior of the infilled RC frames. In this paper, a separate finite element model for simulating the out-of-plane failure mode and capacity of masonry-infilled RC frames is developed using 3-D elements with damage-plasticity material model and the surface-based contact cohesive interaction model simulating the interface between blocks. Comparison between the results of analysis and experiment indicates that the present model can successfully simulate the out-of-plane behavior of the structure.

Integrity Evaluation of Steel Flanges Joined with Metallic Gaskets

2013 ◽  
Vol 554-557 ◽  
pp. 2187-2199
Author(s):  
Ragnar Gjengedal ◽  
Ørjan Fyllingen ◽  
Henrik Sture
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Stainless Steel ◽  
Finite Element Model ◽  
Duplex Stainless Steel ◽  
Element Model ◽  
System Integrity ◽  
Steel Bars ◽  
American Standard ◽  
Manufacturing Methods

System integrity of a flanged connection requires that no leakages occur. Metallic flanges and their joining is of great importance when it comes to avoiding leakages from hydrocarbon lines. The American standard ASTM A182 demands that flanges must be forged to shape, thereby excluding other manufacturing methods. Mechanical properties of duplex stainless steel bars have been examined by doing tensile and charpy tests. A finite element model of a typical ASME-flange assembly was made and was used to calculate stress levels in the flange. The measured mechanical properties of the bar, showed that it is suitable for flange use.

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