An efficient finite element model of surface pit reduction on stainless steel in metal forming processes

2005 ◽  
Vol 170 (1-2) ◽  
pp. 310-316 ◽  
Author(s):  
A. Stephany ◽  
H.R. Le ◽  
M.P.F. Sutcliffe
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Finite Element Model ◽  
Metal Forming ◽  
Element Model

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.

Forming limit diagrams by including the M–K model in finite element simulation considering the effect of bending

2016 ◽  
Vol 232 (8) ◽  
pp. 625-636 ◽  
Author(s):  
Mostafa Habibi ◽  
Ramin Hashemi ◽  
Ahmad Ghazanfari ◽  
Reza Naghdabadi ◽  
Ahmad Assempour
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Metal Forming ◽  
Forming Limit Diagram ◽  
Element Model ◽  
Forming Limit ◽  
Finite Element Models ◽  
Element Simulation ◽  
Simple Tension ◽  
Out Of Plane

Forming limit diagram is often used as a criterion to predict necking initiation in sheet metal forming processes. In this study, the forming limit diagram was obtained through the inclusion of the Marciniak–Kaczynski model in the Nakazima out-of-plane test finite element model and also a flat model. The effect of bending on the forming limit diagram was investigated numerically and experimentally. Data required for this simulation were determined through a simple tension test in three directions. After comparing the results of the flat and Nakazima finite element models with the experimental results, the forming limit diagram computed by the Nakazima finite element model was more convenient with less than 10% at the lower level of the experimental forming limit diagram.

scholarly journals Technological and Theoretical Application of Finite Element Modeling of Deep Drawing

2018 ◽  
Vol 9 (1) ◽  
pp. 51-54
Author(s):  
Ádám Bertók ◽  
Viktor Gonda ◽  
Károly Széll
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Deep Drawing ◽  
Metal Forming ◽  
Element Model ◽  
Stress And Strain ◽  
Element Analysis ◽  
Forming Technology ◽  
Theoretical Application

Abstract For metal forming problems, even for a simple forming technology, finite element analysis can provide a solution for calculating deformations, determining stress and strain distributions. The aim of this study is to create a parametric finite element model for deep drawing technology, by which technological optimization as well as theoretical problems can be solved. By performing parameter studies, numerous cases can be analyzed.

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.

Effect of Marangoni Convection on Welding Pool of Plasma Direct Metal Forming Finite Element Model

2011 ◽  
Vol 704-705 ◽  
pp. 674-679
Author(s):  
Dan Xia ◽  
Bin Shi Xu ◽  
Yao Hui Lv ◽  
Yi Jiang ◽  
Cun Long Liu
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Finite Element Model ◽  
Metal Forming ◽  
Molten Pool ◽  
Marangoni Convection ◽  
Element Model ◽  
Metal Powders ◽  
Forming Process ◽  
Metal Forming Process

With considering the Marangoni convection in the molten pool on plasma direct metal forming process, a finite element model posed to describe and reflect the flow in the molten pool. Results of temperature distribution modeling prepared by plasma direct metal forming process of metal powders in an Ar environment were numerically obtained and compared with experimental data. Powders of Fe314 and base plates of R235 steel were taken as sample materials. In the experiment a multi-stream nozzle capable of delivering metal powder coaxially with the plasma arc was used. The model revealed that the velosity of the front part of the pool is a little slower than aft part. Marangoni convection reinforced the convection and enhanced the heat transfer. Profile of the model is the same as the experimental data. This allows us to conclude that the model can be applied for preselecting the process parameters. Keywords: plasma, rapid forming, temperature field, Marangoni convection.

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.

The Potential and Application Areas of Forging Aided by Shear Stress

2013 ◽  
Vol 212 ◽  
pp. 91-94
Author(s):  
Marek Tkocz ◽  
Zdzisław Cyganek ◽  
Franciszek Grosman
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Finite Element Model ◽  
Numerical Simulations ◽  
Metal Forming ◽  
Material Flow ◽  
Strain Distribution ◽  
Vertical Motion ◽  
Element Model ◽  
Local Strains

The paper demonstrates the potential of unconventional metal forming method that consists in introducing shear stress at the die/workpiece interface during compression. In practice it can be realized by induction of reciprocating, vertical motion of a punch that adheres strongly to a workpiece. To estimate an effect of the method on the material flow, a relevant finite element model has been developed and the selected results of numerical simulations are presented in the paper. In comparison to the conventional forging, forming aided by shear stress is able to provide a number of benefits such as significant increase of local strains, lower press loads and the opportunity to control the strain distribution in the workpiece volume. Perspectives for continuation of the studies as well as possible application areas of forging aided by shear stress are discussed in the summary.

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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