Basic Studies for the Automatic Fabrication of Welded Built-up Beams

1995 ◽  
Vol 11 (02) ◽  
pp. 111-116 ◽  
Author(s):  
Chang Doo Jang ◽  
Seung II Seo
Keyword(s):  
Welding Current ◽  
Simulation Method ◽  
Welding Deformation ◽  
Skilled Workers ◽  
Fabrication Cost ◽  
Current Voltage ◽  
Fabrication Procedure ◽  
Increase In Productivity ◽  
Study Techniques ◽  
Basic Studies

In the fabrication of welded built-up beams, longitudinal deformation occurs due to welding. As it prevents improvement of productivity and quality, heating for straightening the welding deformation is necessary. Therefore, control of the deformation due to welding and heating is the base for the automatic fabrication of built-up beams. In this study, techniques to control the deformation are developed. Based on the simple formulas for estimation of the deformation proposed in the previous study, a procedure to calculate the required reverse curvatures to straighten the welding deformation is presented and a method to simulate the fabrication procedure is developed. From the simulation of the fabrication procedure it is concluded that, in heating for straightening, deep-heated depth is more economical than wide-heated breadth in yielding the same curvature. To apply the results obtained to automatic fabrication, welding and heating parameters such as welding current, voltage and speed, and heated depth and breadth are selected and fabrication cost is expressed by the parameters, which are optimized under the constraints. According to the optimized results, the higher welding current reduces the fabrication cost. Results obtained through executing the simulation method described herein can be used in the guidance of welding and heating procedures instead of depending on the experience of skilled workers--and this can contribute to an increase in productivity and quality.

Effect of Stretching during Welding Process on the Weldability of Dissimillar Metals Resistance Spot Welded between Carbon Steel and Low Nickel Stainless Steel

2014 ◽  
Vol 894 ◽  
pp. 206-211 ◽  
Author(s):  
Triyono ◽  
Heru Sukanto ◽  
Nurul Muhayat ◽  
Sutiyono
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Local Heating ◽  
Welding Process ◽  
Welding Current ◽  
Welding Deformation ◽  
Tensile Shear ◽  
Resistance Spot ◽  
Weld Time ◽  
Different Levels

Due to the local heating of welding, deformation will occur on the welding structure. To mitigate this deformation, the method called stretching technology was proposed by previous study. In this method, plate was stretched to certain pre-strain, kept in this condition and then welded to another sheet. It can reduce the welding deformation significantly. However, pre-strain will change the properties of joined materials and lead different behavior of welded materials. It will be complicated if dissimilar metals are welded due to different physical and metallurgical properties. Carbon steel SS400 with the thickness of 3.0 mm and 1.0 mm thick-low nickel stainless steel were welded using resistance spot welding (RSW) process with constant electrode pressure and weld time of 6 kN and 5 second respectively. During welding process, low nickel stainless steel was stretched in four different levels pre-strain of 0%, 1%, 1.5% and 2%. Welding current were varied in the range from 3.02 to 4.20 kA. Microstructure investigations and tensile-shear tests were conducted to evaluate the weldability of RSW joint. Generally, stretching during welding process decreased the fussion zone area of RSW joint. In the low welding current, there is no fussion in the interface of stretched plate, but fussion still occured in the interface of unstretched plate. In all levels of welding current, stretching during welding decreased fussion zone area and led to decrease tensile-shear load bearing capacity of RSW joint.

Numerical Analysis of Controlling Welding Deformation of the Wall Plate of Large Cylindrical Structure by Pre-Stress Method

2011 ◽  
Vol 189-193 ◽  
pp. 3351-3354 ◽  
Author(s):  
Chun Yuan Shi ◽  
Qing Yuan Meng ◽  
Cheng Jin
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Stress Level ◽  
Simulation Method ◽  
Welding Deformation ◽  
Cylindrical Structure ◽  
Numerical Simulation Method ◽  
Welding Sequence ◽  
Final Deformation

During the welding of the wall plate of cylindrical structure, the edges of cylinder generates obvious wave-like deformation and affects subsequent assembly. In this paper, based on the numerical simulation method, welding deformation controlling by pre-stress method is studied. The effects of the pre-stress level and the welding sequence on the final deformation are discussed. The results show that the level of pre-stress can obviously control the welding deformation of the longitudinal beams, but can not control the welding deformation of transverse beams. Using the selected welding sequence: welding transverse beams firstly, exerting pre-stress, and then welding longitudinal beams, this welding sequence can reduce the wave-like deformation after welding.

Welding Distortion Simulation of Large Stiffened Plate Panels

2008 ◽  
Vol 24 (01) ◽  
pp. 50-56
Author(s):  
Pankaj Biswas ◽  
N. R. Mandal
Keyword(s):  
Structural Integrity ◽  
Plate Thickness ◽  
Welding Current ◽  
Fusion Welding ◽  
Welding Distortion ◽  
Element Analysis ◽  
Stiffened Panels ◽  
Analysis Methodology ◽  
Current Voltage ◽  
Plate Panels

Fusion welding leads to heat-induced distortion. These deformations may adversely affect the structural integrity and subsequent alignment of the adjacent panels. The extent of distortion depends on several parameters such as welding speed, plate thickness, welding current, voltage, restraints applied to the job while welding, as well as sequence of welding. Welding being a transient phenomenon, finite element analysis of large stiffened panels is virtually not possible. In the present work, an analysis methodology based on the quasi-stationary nature of welding and the resulting symmetric behavior of the stiffened panels has been developed for studying the distortion pattern of orthogonally stiffened large plate panels. The effect of filler metal deposition has been taken into account by implementing element birth and death technique. The numerical model yielded results comparing well with the ex- perimental results.

Angular Distortion Due to Fillet Welding and Its Straightening

2000 ◽  
Vol 16 (02) ◽  
pp. 90-96
Author(s):  
Yasuhisa Okumoto ◽  
Hideharu Yanai ◽  
Shin-ich Matsuzaki
Keyword(s):  
Production System ◽  
Production Line ◽  
Dimensional Accuracy ◽  
Fem Analysis ◽  
Ship Hull ◽  
Angular Distortion ◽  
Welding Deformation ◽  
Skilled Workers ◽  
Automated Production ◽  
Press Roller

In order to increase the productivity of shipbuilding to respond to current situations such as decreasing numbers of skilled workers and aging of workers in the shipyard, mechanization and robotization have been accelerated. To apply them effectively, the current fabrication and assembling system of ship hull has to be reviewed so that the dimensional accuracy of the hull block and its components increase particularly. Accordingly, the authors had developed an "accurate production system" for the fabrication and assembly of flat block, which was based on advanced accuracy technology and modem automated machines. This report concerns the deformation due to the filet welding of longitudinals on a skin plate and its straightening; the estimation of welding deformation, especially angular distortion, and its straightening method using a press roller which was developed newly in this automated production line. In order to clarify the power of the straightening machine, non-linear FEM analysis was carried out.

Numerical Simulation of Sheet to Cylindrical Tube Single-Sided Spot Welding

2012 ◽  
Vol 443-444 ◽  
pp. 684-687
Author(s):  
Hong Gang Yang
Keyword(s):  
Numerical Simulation ◽  
Automobile Industry ◽  
Spot Welding ◽  
Cylindrical Tube ◽  
Element Model ◽  
Simulation Method ◽  
Welding Deformation ◽  
Electrode Displacement ◽  
Lightweight Structure ◽  
Different Parts

With the promotion of lightweight structure, hydroformed tubes have been widely used in the automobile industry. In order to join different parts, sheet to tube single-sided spot welding (SSSW) is proposed. In the present study, numerical simulation method is employed, and an electrical-thermal mechanical coupled finite element model is established for predicting the nugget size and shape of sheet to cylindrical tube SSSW. Because of the welding deformation, doughnut weld nugget is formed and the course of the welding deformation can be reflected by the electrode displacement.

Optimization of Block Erection Using a Genetic Algorithm

2002 ◽  
Vol 18 (02) ◽  
pp. 116-119
Author(s):  
Yasuhisa Okumoto
Keyword(s):  
Genetic Algorithm ◽  
Computer Simulation ◽  
Simulation Method ◽  
Measurement Technology ◽  
Skilled Workers ◽  
Productivity Improvement ◽  
Optimum Position ◽  
Efficient Measurement ◽  
Dimensional Errors ◽  
Positional Control

Block erection is a very important and demanding skill in shipbuilding quality control as well as in productivity improvement. Though this work at the present time depends on skilled workers in the yards, these workers eventually become old and retire, and then the training of their successors, or other countermeasures, will be required. Recently, CAD and CIM systems have been applied widely, and also efficient measurement technology has been developed in the shipyard; thus it has become possible to apply positional control at the erection stage by computer simulation. This paper presents a computer simulation method to place a block, which has dimensional errors, in a suitable position as designed using a genetic algorithm (GA). A pilot program using a personal computer has been developed and applied to a typical hexahedron block. The simulation results showed good agreement in achieving the optimum position.

Investigations of Electrostatic and Ionized Fields Analysis for Dual-Electrode System

2016 ◽  
Vol 3 (1) ◽  
pp. 80
Author(s):  
Mohamed A. Abouelatta ◽  
Abdelhadi R. Salama ◽  
A. M. Omar ◽  
S. A. Ward
Keyword(s):  
Electric Field ◽  
Electrostatic Field ◽  
Simulation Method ◽  
Electrode System ◽  
Charge Simulation Method ◽  
Density Profiles ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Ion Current Density ◽  
Good Agreement

<p>The paper presents the computation and measurement of electric field, in both electrostatic as well as ionized case, for dual electrode system intended for electrostatic applications. The dual electrode system consists of an ionizing and non-ionizing electrode have the same voltage and facing a grounded collecting plate. The charge simulation method (CSM) coupled with genetic algorithms (GAs) and method of characteristic (MOC) is applied to compute the electrostatic field and the ionized field respectively. The influence of dual system parameters such as ionized wire diameter and inter electrode distances on the profile of the electrostatic field on the collecting plate and on the surface of the ionizing wire has been studied. The measurements of the ionized electric field, current-voltage characteristics and ion current density profiles are implemented using the technique of the linear biased probe. An experimental setup is constructed to model the present electrode arrangement. The measurements are carried out for ionized wire of diameter 0.25 and 0.5mm. The computed results are found to be in good agreement with experiments.</p>

scholarly journals Reduction of power consumption during arc welding operation

2018 ◽  
Vol 245 ◽  
pp. 05001
Author(s):  
Liudmila Sakhno ◽  
Olga Sakhno ◽  
Vitaliy Boronin ◽  
Elena Kochetkova ◽  
Chen Hao
Keyword(s):  
Energy Saving ◽  
Arc Welding ◽  
Electronic Device ◽  
Economic Effect ◽  
Welding Current ◽  
Power Sources ◽  
Welding Equipment ◽  
Assembly Shop ◽  
Current Voltage ◽  
Bridge Rectifier

The work is devoted to energy saving during arc manual welding operations. Power sources for arc manual welding are rectifiers with slow or steeply falling current-voltage characteristics. The paper considers two ways of energy saving during arc welding operations. The first way is to increase the efficiency of welding by replacing the ballast rheostat with a special electronic device that regulates the welding current instead of the ballast rheostat. The second way is to increase the efficiency of the welding equipment by replacing a traditional one-bridge rectifier with the two-bridge economical rectifier. An approximate calculation of the annual economic effect from the replacement of a ballast rheostat by the electronic regulating device is given on the example of welding operations in a typical assembly shop.

scholarly journals Prediction of tungsten insert gas welding process parameter using design of experiment and fuzzy logic

2021 ◽  
Vol 4 (2) ◽  
Author(s):  
P. Pondi ◽  
J. Achebo ◽  
A. Ozigagun
Keyword(s):  
Fuzzy Logic ◽  
Mild Steel ◽  
Design Of Experiment ◽  
Heat Input ◽  
Welding Process ◽  
Statistical Design ◽  
Welding Current ◽  
Process Parameter ◽  
Current Voltage ◽  
Input Parameters

The focus of this study is to predict tungsten inert gas (TIG) welding process parameter such as heat input for stabilizing heat and removing post weld crack formation in mild steel weldment. The main input parameters examined are the welding current, voltage and speed whereas the measured (response) parameter is heat input. Statistical design of experiment was done by means of central composite design method using the range and levels of independent variables. The experiment was carried out 20 times (with 5 specimens per run) using 60 mm x 40 mm x 10 mm mild steel coupons. The plate samples were cut longitudinally with a Single-V joint preparation, with the edges beveled. The welding process utilizes 100% pure argon as a protecting gas to shield the weld specimen from external interaction. The interaction between the input and response variables was analyzed using a fuzzy logic system. The result showed that for a welding current, voltage and speed of 190 A, 21 V, and 2.0 mm/s respectively, the predicted heat input was 0.912 kJ/mm whereas for input parameters of (170 A, 25 V, and 2.0 mm/s) and (180 A, 23 V, 0.98 mm/s), the predicted heat inputs were 1.07 kJ/mm and 1.380 kJ/mm, respectively.

scholarly journals A STUDY OF THE CONCEPT OF DYNAMIC EQUIPMENT IN THE EARTHMOVING PROCESS BY A CONSIDERATION OF TIME, COST AND EMISSIONS

2013 ◽  
Vol 8 (3) ◽  
pp. 156-165
Author(s):  
Mojtaba Maghrebi ◽  
Meysam Ebrahiminejad ◽  
Eghbal Shakeri
Keyword(s):  
Discrete Event Simulation ◽  
Discrete Event ◽  
Simulation Method ◽  
Time Cost ◽  
Event Simulation ◽  
The Earth ◽  
Increase In Productivity

The earthmoving process is usually handled by a combination of multi-functional excavators and delivery trucks. According to the principles of excavation, a specific machine is selected to dig the earth. Sometimes, due to the difficulties in the process, the digging process is split between different machines with different capabilities. This paper aims to introduce the concept of dynamic equipment for allocating different tasks in an operation to a machine. This concept is discussed and modelled via a discrete-event simulation method and is tested in a real earthmoving operation from three different perspectives: time, cost and emission. The results from the case study show that the use of dynamic equipment will lead to a decrease in cost and emissions and an increase in productivity.

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