NUMERICAL AND EXPERIMENTAL EVALUATION ON THE RESIDUAL STRESSES OF WELDED JOINTS

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4451-4456
Author(s):  
SUN CHUL HUH ◽  
WONJO PARK ◽  
HAESUG YANG ◽  
HAEYOUNG JUNG ◽  
CHUYOUNG KIM

Wings for the defense industry such as fighters, missiles, and rockets should show no deformation or damage on the structure. The structures of existing wings had holes for weight reduction. The plates and frames were fixed with rivets or screws, which limited the weight reduction possible. In this study, an improvement was made in jointing methods through EB welding and laser welding. Welding strength was measured through tension testing. In addition, finite element analysis was performed for the welding process so as to deduce the optimum welding condition.

2015 ◽  
Vol 752-753 ◽  
pp. 500-504 ◽  
Author(s):  
Adirek Baisukhan ◽  
Wasawat Nakkiew

Tungsten Inert Gas (TIG) welding process requires high heat input during the process, when the material is cooled down non-uniform distribution of thermal strain causes residual stress which can weaken the material and fatigue life of the material. The residual stress can be measured from method such as x-ray diffraction (XRD), using strain gage of drilled hole and so on. A numerical method of constructing a finite element analysis (FEA) model can be used for predicting the residual stress level of the welding process. This paper uses the TIG welding condition for stainless steel grade 304 that the material provided the highest level of tensile strength, obtained from previous study, as a condition for the FEA model. The residual stress results from the FEA predictive model and the results from XRD were compared. In the FEA model, the workpiece, heat affected zone (HAZ), and filler metal assumed to be the same. The results showed consistent residual profile between the model and the actual measurement from XRD, but there was some discrepancy of the magnitude of residual stress which can due to the type of filler material that was used.


2013 ◽  
Vol 774-776 ◽  
pp. 1155-1159 ◽  
Author(s):  
Xiao Cong He

Friction stir welding (FSW) is a solid-state welding process where no gross melting of the material being welded takes place. Numerical modelling of the FSW process can provide realistic prediction of the thermo-mechanical behaviour of the process. Latest literature relating to finite element analysis (FEA) of thermo-mechanical behaviour of FSW process is reviewed in this paper. The recent development in thermo-mechanical modelling of FSW process is described with particular reference to two major factors that influence the performance of FSW joints: material flow and temperature distribution. The main thermo-mechanical modelling used in FSW process are discussed and illustrated with brief case studies from the literature.


2012 ◽  
Vol 490-495 ◽  
pp. 2785-2789
Author(s):  
Dong Sun ◽  
Xu Dong Yang

The milling planer bed is one of the most important foundational parts for the entire machine, sufficient stiffness is required. The posterior segment of a certain milling planer bed is regarded as the optimization object in this paper. Three-dimensional modeling method is used to calculate the exact weight of the bed and then finite element analysis is used to research the static and dynamic characteristics before and after weight-reduction. The weak link of the bed is found out and a improvement scheme is put forward ensuring lower production costs under the premise of sufficient rigidity.


2016 ◽  
Vol 707 ◽  
pp. 154-158
Author(s):  
Somsak Limwongsakorn ◽  
Wasawat Nakkiew ◽  
Adirek Baisukhan

The proposed finite element analysis (FEA) model was constructed using FEA simulation software, ANSYS program, for determining effects of corrosion fatigue (CF) from TIG welding process on AISI 304 stainless steel workpiece. The FEA model of TIG welding process was developed from Goldak's double ellipsoid moving heat source. In this paper, the residual stress results obtained from the FEA model were consistent with results from the X-ray diffraction (XRD) method. The residual stress was further used as an input in the next step of corrosion fatigue analysis. The predictive CF life result obtained from the FEA CF model were consistent with the value obtained from stress-life curve (S-N curve) from the reference literaturature. Therefore, the proposed FEA of CF model was then used for predicting the corrosion fatigue life on TIG welding workpiece, the results from the model showed the corrosion fatigue life of 1,794 cycles with testing condition of the frequency ( f ) = 0.1 Hz and the equivalent load of 67.5 kN (equal to 150 MPa) with R = 0.25.


Author(s):  
Shivdayal Patel ◽  
B. P. Patel ◽  
Suhail Ahmad

Welding is one of the most used joining methods in the ship industry. However, residual stresses are induced in the welded joints due to the rapid heating and cooling leading to inhomogenously distributed dimensional changes and non-uniform plastic and thermal strains. A number of factors, such as welding speed, boundary conditions, weld geometry, weld thickness, welding current/voltage, number of weld passes, pre-/post-heating etc, influence the residual stress distribution. The main aim of this work is to estimate the residual stresses in welded joints through finite element analysis and to investigate the effects of boundary conditions, welding speed and plate thickness on through the thickness/surface distributions of residual stresses. The welding process is simulated using 3D Finite element model in ABAQUS FE software in two steps: 1. Transient thermal analysis and 2. Quasi-static thermo-elasto-plastic analysis. The normal residual stresses along and across the weld in the weld tow region are found to be significant with nonlinear distribution. The residual stresses increase with the increase in the thickness of the plates being welded. The nature of the normal residual stress along the weld is found to be tensile-compressive-tensile and the nature of normal residual stress across the weld is found to be tensile along the thickness direction.


2020 ◽  
Vol 21 (2) ◽  
pp. 513-518
Author(s):  
Erinç Uludamar ◽  
Mustafa Taş ◽  
Sami Gökberk Biçer ◽  
Cihan Yıldırım ◽  
Ebru Aykut Yıldırım ◽  
...  

Author(s):  
Robbin Bertucci ◽  
Jun Liao ◽  
Lakiesha Williams

Explosions are the leading cause of death on the battlefield [1]. These explosives generate shock waves which stimulate large accelerations and deformations. The resulting loads pose serious threats to military and civilians. Since lower extremities are in direct contact with the ground, the lower extremities are commonly injured during explosions [2]. These injuries could be seriously fatal. Although experimental studies have been performed to advance these understandings [2], limited progress has been made in computational analysis of shock waves on the lower extremity.


Author(s):  
N. RAJESH JESUDOSS HYNES ◽  
P. NAGARAJ ◽  
S. JOSHUA BASIL

The joining of ceramic and metals can be done by different techniques such as ultrasonic joining, brazing, transient liquid phase diffusion bonding, and friction welding. Friction Welding is a solid state joining process that generates heat through mechanical friction between a moving workpiece and a stationary component. In this article, numerical simulation on thermal analysis of friction welded ceramic/metal joint has been carried out by using Finite Element Analysis (FEA) software. The finite element analysis helps in better understanding of the friction welding process of joining ceramics with metals and it is important to calculate temperature and stress fields during the welding process. Based on the obtained temperature distribution the graphs were plotted between the lengths of the joint corresponding to the temperatures. To increase the wettability, aluminium sheet was used as an interlayer. Hence, numerical simulation of friction welding process is done by varying the interlayer sheet thickness. Transient thermal analysis had been carried out for each cases and temperature distribution was studied. From the simulation studies, it is found that the increase in interlayer thickness reduces the heat affected zone and eventually improves the joint efficiency of alumina/aluminum alloy joints.


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