scholarly journals Numarical Simulation of Temperature, Misrostructure, and Stress-Strain Behaviors during Welding Process-Approach to Prediction Tool on Joint Performance in Welded Structures-

2003 ◽  
Vol 72 (8) ◽  
pp. 631-639
Author(s):  
Masahito MOCHIZUKI ◽  
Masao TOYODA
Keyword(s):  
Welding Process ◽  
Process Approach ◽  
Prediction Tool ◽  
Stress Strain ◽  
Welded Structures ◽  
Joint Performance

scholarly journals Predicting Welding Distortion in a Panel Structure with Longitudinal Stiffeners Using Inherent Deformations Obtained by Inverse Analysis Method

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Wei Liang ◽  
Hidekazu Murakawa
Keyword(s):  
Inverse Analysis ◽  
Welding Process ◽  
Strain Theory ◽  
The Other ◽  
Welding Distortion ◽  
Welding Deformation ◽  
Welded Structures ◽  
Longitudinal Stiffeners ◽  
Manufacturing Accuracy ◽  
Inherent Strain

Welding-induced deformation not only negatively affects dimension accuracy but also degrades the performance of product. If welding deformation can be accurately predicted beforehand, the predictions will be helpful for finding effective methods to improve manufacturing accuracy. Till now, there are two kinds of finite element method (FEM) which can be used to simulate welding deformation. One is the thermal elastic plastic FEM and the other is elastic FEM based on inherent strain theory. The former only can be used to calculate welding deformation for small or medium scale welded structures due to the limitation of computing speed. On the other hand, the latter is an effective method to estimate the total welding distortion for large and complex welded structures even though it neglects the detailed welding process. When the elastic FEM is used to calculate the welding-induced deformation for a large structure, the inherent deformations in each typical joint should be obtained beforehand. In this paper, a new method based on inverse analysis was proposed to obtain the inherent deformations for weld joints. Through introducing the inherent deformations obtained by the proposed method into the elastic FEM based on inherent strain theory, we predicted the welding deformation of a panel structure with two longitudinal stiffeners. In addition, experiments were carried out to verify the simulation results.

A smart prediction tool for estimating the impact strength of welded joints prepared by vibratory welding process

2016 ◽  
Vol 231 (2) ◽  
pp. 343-346 ◽  
Author(s):  
P Govinda Rao ◽  
P Srinivasa Rao ◽  
A Gopala Krishna
Keyword(s):  
Impact Strength ◽  
Welded Joints ◽  
Welding Process ◽  
Input Voltage ◽  
Grain Structure ◽  
Generalized Regression Neural Network ◽  
Prediction Tool ◽  
Fine Grain ◽  
Vibration Parameters ◽  
The Impact

Previous researches have been devoted to development of vibratory setup for inducing mechanical vibrations into the weld pool during welding process. The designed vibratory setup produces the required frequency with suitable amplitude and acceleration in terms of voltages. This helps in producing uniform and fine grain structure in the welded joints which results in an improvement in the mechanical properties of the weld pieces at heat affected zone. This paper presents the development of a smart prediction tool by implementing generalized regression neural network to establish a relation between vibration parameters such as input voltage to the vibromotor, time of vibration and impact strength of vibratory weld joints. In order to validate the feasibility of the developed prediction tool, a comparison is made with the experimental results.

Determination of some Mechanical Characteristics by Vibration Testing of Welded Structures with Tubular Wire

2013 ◽  
Vol 814 ◽  
pp. 127-134 ◽  
Author(s):  
Liviu Bereteu ◽  
Raul Moisa ◽  
Mihaela Popescu ◽  
Gheorghe Drăgănescu ◽  
Radu Alexandru Rosu ◽  
...  
Keyword(s):  
Steel Wire ◽  
Welding Process ◽  
Tensile Tests ◽  
Operating Conditions ◽  
Steel Plates ◽  
Vibration Testing ◽  
Welded Structures ◽  
Appropriate Behavior ◽  
Welded Structure

Applicability of the welded structures in different operating conditions requires experimental research developed in conditions previously imposed for each punctual application. There are analyzed in this case, in terms of vibration testing, some welded joints made with usual tubular steel wire. This is the case of the type carbon steel plates S235 JR according to EN 10025, with a thickness of 3 mm welded with MIG/MAG welding process with R713 tubular wire with a diameter of 1.2 mm, using SelcoNeoMig 3500 equipment. By processing the received signal based on the vibrations response to determine the elastic modulus of the welded structure, which will then be compared both with the modulus value obtained by tensile tests, and with the theoretical value obtained. The results thus obtained will be the basis of design, in optimal conditions of the welded structures regarding the appropriate behavior to the demands imposed.

Tensile and Toughness Properties of Pipeline Girth Welds

2006 ◽  
Author(s):  
J. A. Gianetto ◽  
J. T. Bowker ◽  
R. Bouchard ◽  
D. V. Dorling ◽  
D. Horsley
Keyword(s):  
Weld Metal ◽  
Welding Process ◽  
Strain Curve ◽  
High Strength ◽  
Primary Objective ◽  
Stress Strain ◽  
Line Pipe ◽  
Arc Welding Process ◽  
Girth Welds ◽  
Metal Microstructure

The primary objective of this study was to develop a better understanding of all-weld-metal tensile testing using both round and strip tensile specimens in order to establish the variation of weld metal strength with respect to test specimen through-thickness position as well as the location around the circumference of a given girth weld. Results from a series of high strength pipeline girth welds have shown that there can be considerable differences in measured engineering 0.2% offset and 0.5% extension yield strengths using round and strip tensile specimens. To determine whether or not the specimen type influenced the observed stress-strain behaviour a series of tests were conducted on high strength X70, X80 and X100 line pipe steels and two double joint welds produced in X70 linepipe using a double-submerged-arc welding process. These results confirmed that the same form of stress-strain curve is obtained with both round and strip tensile specimens, although with the narrowest strip specimen slightly higher strengths were observed for the X70 and X100 linepipe steels. For the double joint welds the discontinuous stress-strain curves were observed for both the round and modified strip specimens. Tests conducted on the rolled X100 mechanized girth welds established that the round bar tensile specimens exhibited higher strength than the strip specimens. In addition, the trends for the split-strip specimens, which consistently exhibit lower strength for the specimen towards the OD and higher for the mid-thickness positioned specimen has also been confirmed. This further substantiates the through-thickness strength variation that has been observed in other X100 narrow gap welds. A second objective of this study was to provide an evaluation of the weld metal toughness and to characterize the weld metal microstructure for the series of mechanized girth welds examined.

Spatially Resolved Materials Property Data From a Uniaxial Cross-Weld Tensile Test

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
M. Turski ◽  
M. C. Smith ◽  
P. J. Bouchard ◽  
L. Edwards ◽  
P. J. Withers
Keyword(s):  
Plastic Strain ◽  
Weld Metal ◽  
Speckle Pattern ◽  
Welding Process ◽  
Parent Material ◽  
Image Correlation ◽  
Electronic Speckle Pattern Interferometry ◽  
Stress Strain ◽  
Spatially Resolved ◽  
Process Work

Application of electronic speckle pattern interferometry (ESPI) is described to measure the spatial variation in monotonic tensile stress-strain properties along “cross-weld” specimens machined from a stainless steel three-pass welded plate. The technique, which could also be done with digital image correlation, was applied to quantify how the material 0.2%, 1%, 2%, 5%, 10%, and 20% proof stress varied with distance from the center-line of the weldment for parent and weld material associated with the first and final passes. The stress-strain curves measured by the ESPI method correlated closely with stress-strain data measured using conventional test specimens. The measured results are consistent with the hypothesis that thermo-mechanical cycles associated with the welding process work harden previously deposited (single-pass) weld metal and the surrounding parent material. The stress-strain response of the heat affected zone adjacent to the first weld pass is consistent with an accumulated (equivalent monotonic) plastic strain of 6.5% and that of the first pass weld bead was consistent with an accumulated plastic strain of approximately 4% greater than the state of the final pass weld metal.

Computation of HAZ Hardness for Low Alloyed Welded Steels Using Five-Parameter Logistic Function

2014 ◽  
Vol 216 ◽  
pp. 103-109
Author(s):  
Marius Bodea ◽  
Radu Mureşan
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Chemical Composition ◽  
Heat Flow ◽  
Welding Process ◽  
Logistic Function ◽  
Steel Plates ◽  
Maximum Hardness ◽  
Welded Structures ◽  
Asymmetric Data

The mechanical properties of the welded structures are directly related to the weldability of the steels, thus the estimation of the microstructural constituents in the weld and maximum hardness in the HAZ according to the welding process parameters represent a problem of great interest. The microstructural changes in the HAZ are estimated using a five-parameter logistic function (5PL), which is very accurate in the fitting highly asymmetric data. Also, the same 5PL function can be used in order to predict hardness and toughness in the HAZ based on the heat flow, cooling rates between 800-500 oC and chemical composition of the material. A discussion about the parameters of the 5PL function and fitting experimental data is presented and a studied case for welding S355J2 steel plates is also analyzed.

Coupled Field Analysis of a Gas Tungsten Arc Welded Butt Joint—Part I: Improved Modeling

2013 ◽  
Vol 5 (1) ◽  
Author(s):  
D. Sen ◽  
M. A. Pierson ◽  
K. S. Ball
Keyword(s):  
Weld Pool ◽  
Welding Process ◽  
Butt Joint ◽  
Accurate Estimation ◽  
Mathematical Framework ◽  
Welded Structures ◽  
Thermally Induced ◽  
Gas Tungsten Arc ◽  
Welded Structure ◽  
Gas Tungsten

Thermally induced residual stresses due to welding can significantly impair the performance and reliability of welded structures. From a structural integrity perspective of welded structures, it is necessary to have an accurate spatial and temporal thermal distribution in the welded structure before stress analysis is performed. Existing research has ignored the effect of fluid flow in the weld pool on the temperature field of the welded joint. Previous research has established that the weld pool depth/width (D/W) ratio and heat affected zone (HAZ) are significantly altered by the weld pool dynamics. Hence, for a more accurate estimation of the thermally induced stresses it is desired to incorporate the weld pool dynamics into the analysis. Moreover, the effects of microstructure evolution in the HAZ on the mechanical behavior of the structure need to be included in the analysis for better mechanical response prediction. In this study, a three-dimensional numerical model for the thermomechanical analysis of gas tungsten arc (GTA) welding of thin stainless steel butt-joint plates has been developed. The model incorporates the effects of thermal energy redistribution through weld pool dynamics into the structural behavior calculations. Through material modeling the effects of microstructure change/phase transformation are indirectly included in the model. The developed weld pool dynamics model includes the effects of current, arc length, and electrode angle on the heat flux and current density distributions. All the major weld pool driving forces are included, namely surface tension gradient induced convection, plasma induced drag force, electromagnetic force, and buoyancy. The weld D/W predictions are validated with experimental results. They agree well. The workpiece deformation and stress distributions are also highlighted. The mathematical framework developed here serves as a robust tool for better quantification of thermally induced stress evolution and distribution in a welded structure by coupling the different fields in a welding process.

scholarly journals Tensile stress-strain analysis of resistance spot weld using non-linear FEM with experimental verification

2021 ◽  
Vol 66 (1) ◽  
pp. 5-21
Author(s):  
Nazri Mohd ◽  
Emri Wan ◽  
Yupiter Manurung ◽  
Micheal Stoschka ◽  
Muhammad Suhaimi ◽  
...  
Keyword(s):  
Tensile Test ◽  
Fem Simulation ◽  
Low Carbon Steel ◽  
Welding Process ◽  
Strain Analysis ◽  
Spot Weld ◽  
Low Carbon ◽  
Stress Strain ◽  
Resistance Spot ◽  
Resistance Spot Weld

This research presents an investigation on stress-strain behavior induced by resistance spot weld followed by tensile shear test. The spot weld is modeled according to standardized dimension for tensile test with main material properties of Cu as electrode and low carbon steel S235 as plates with 1mm thickness which include electric conductivity, resistivity and heat transfer coefficient for solid body as well as a contact interface. The FEM simulation is conducted using the process parameter of current between 6,000 A to 15,000 A, force at 5,000 N and different stages of time following the welding process and tensile test which is carried out after releasing both of the electrodes and material reaches the initial temperature with contact clamp velocity of 5mm/min. To ensure the glued elements between the plates, subroutine in MSC Marc/Mentat is used in the simulation with defined temperature. The outcome of simulation results will be verified with series of experiments. It is expected that simulation will give good agreement compared to experimental analysis within acceptable range of error.

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