Experimental Verification of Distortion Analysis of Welded Stiffeners

2002 ◽  
Vol 18 (04) ◽  
pp. 216-225
Author(s):  
M. V. Deo ◽  
P. Michaleris
Keyword(s):  
Experimental Verification ◽  
Experimental Validation ◽  
Welding Process ◽  
Computational Results ◽  
Buckling Mode ◽  
Fea Model ◽  
Buckling Stress ◽  
Distortion Analysis ◽  
Process Simulations ◽  
Buckling Distortion

This paper presents an experimental verification for the predictive distortion analysis approach proposed in Michaleris & DeBicarri (1996,1997) and Vanli & Michaleris (2001) for welded T-type stiffeners. The predictive technique employing the decoupled 2-D and 3-D approach is used for the prediction of buckling distortion and the magnitude of bowing distortion. Two-dimensional thermo-mechanical welding process simulations are performed to determine the residual stress. The critical buckling stress along with the buckling mode are computed in 3-D eigenvalue analyses. Large deformation analyses are carried out to predict the magnitude of bowing distortion. Experimental validation of the prediction is carried out in the lab. Welding experiments are carried out using welding conditions identical to those used in the FEA model. The computational results are then verified with experimental observations

Distortion Analysis of Welded Stiffeners

2001 ◽  
Vol 17 (04) ◽  
pp. 226-240 ◽  
Author(s):  
O. A. Vanli ◽  
P. Michaleris
Keyword(s):  
Residual Stress ◽  
Heat Input ◽  
Welding Process ◽  
Angular Distortion ◽  
Welding Distortion ◽  
Two Dimensional ◽  
Buckling Mode ◽  
Buckling Stress ◽  
Distortion Analysis ◽  
Process Simulations

This paper presents a welding distortion analysis approach for T-stiffeners with a particular emphasis on welding-induced buckling instabilities. Two-dimensional thermomechanical welding process simulations are performed to determine the residual stress and angular distortion. This critical buckling stress along with the buckling mode and bowing distortion are computed in 3-D eigenvalue and linear stress analyses. The effects of the stiffener geometry, weld sequence, weld heat input and mechanical fixturing on the occurrence of buckling and the distortion pattern are investigated.

ELASTIC BUCKLING OF THIN-WALLED CIRCULAR TUBES CONTAINING AN ELASTIC INFILL

2006 ◽  
Vol 06 (04) ◽  
pp. 457-474 ◽  
Author(s):  
M. A. BRADFORD ◽  
A. ROUFEGARINEJAD ◽  
Z. VRCELJ
Keyword(s):  
Axial Compression ◽  
A Priori ◽  
Local Buckling ◽  
Steel Tube ◽  
Transcendental Equation ◽  
Buckling Mode ◽  
Buckling Stress ◽  
Elastic Tubes ◽  
Thin Walled ◽  
Energy Formulation

Circular thin-walled elastic tubes under concentric axial loading usually fail by shell buckling, and in practical design procedures the buckling load can be determined by modifying the local buckling stress to account empirically for the imperfection sensitive response that is typical in Donnell shell theory. While the local buckling stress of a hollow thin-walled tube under concentric axial compression has a solution in closed form, that of a thin-walled circular tube with an elastic infill, which restrains the local buckling mode, has received far less attention. This paper addresses the local buckling of a tubular member subjected to axial compression, and formulates an energy-based technique for determining the local buckling stress as a function of the stiffness of the elastic infill by recourse to a transcendental equation. This simple energy formulation, with one degree of buckling freedom, shows that the elastic local buckling stress increases from 1 to [Formula: see text] times that of a hollow tube as the stiffness of the elastic infill increases from zero to infinity; the latter case being typical of that of a concrete-filled steel tube. The energy formulation is then recast into a multi-degree of freedom matrix stiffness format, in which the function for the buckling mode is a Fourier representation satisfying, a priori, the necessary kinematic condition that the buckling deformation vanishes at the point where it enters the elastic medium. The solution is shown to converge rapidly, and demonstrates that the simple transcendental formulation provides a sufficiently accurate representation of the buckling problem.

Some Observations on the Compressive Buckling of Rectangular Plates

1963 ◽  
Vol 14 (1) ◽  
pp. 17-30 ◽  
Author(s):  
W. H. Wittrick
Keyword(s):  
Rate Of Change ◽  
Infinite Strip ◽  
Rectangular Plates ◽  
Buckling Mode ◽  
Simply Supported ◽  
Side Ratio ◽  
Buckling Stress ◽  
Stress Coefficient ◽  
Wide Range ◽  
Elastically Restrained

SummaryThe problem considered is the buckling of a rectangular plate under uniaxial compression. The ends may be either both clamped, both simply-supported or a mixture of the two. The sides may be elastically restrained against both deflection and rotation with any stiffnesses whatsoever. It is shown that the curve of buckling stress coefficient versus side ratio can be deduced in a simple manner from that of a plate with the same end conditions but with both sides simply-supported, provided only that the buckling stress coefficient and wavelength for an infinite strip with the same side conditions are known. Some correlations between the curves for the three types of end condition are discussed. It is also shown that if, for some given side ratio, the buckling mode is known, then it is always possible to deduce the rate of change of buckling stress coefficient with side ratio at that point. The argument is based upon an assumption which is shown to give very accurate results in a wide range of cases.

Finite Element Analysis Model of Corrosion Fatigue for TIG Welding Workpiece

2016 ◽  
Vol 707 ◽  
pp. 154-158
Author(s):  
Somsak Limwongsakorn ◽  
Wasawat Nakkiew ◽  
Adirek Baisukhan
Keyword(s):  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
Corrosion Fatigue ◽  
Welding Process ◽  
Simulation Software ◽  
Tig Welding ◽  
Element Analysis ◽  
Fea Model

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.

A Computational Model of Backlay Welding for Controlling Residual Stresses in Welded Pipes

1981 ◽  
Vol 103 (3) ◽  
pp. 226-232 ◽  
Author(s):  
F. W. Brust ◽  
E. F. Rybicki
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Computational Model ◽  
Welding Process ◽  
Computational Results ◽  
Intergranular Stress Corrosion ◽  
Inner Surface ◽  
Piping Systems ◽  
Intergranular Stress Corrosion Cracking ◽  
Compressive Residual Stresses

Intergranular Stress Corrosion Cracking (IGSCC) has been a problem in Boiling Water Reactor (BWR) piping systems. One method for retarding IGSCC is to eliminate tensile residual stresses at the pipe inner surface in the heat affected zone produced by the welding process. A method called backlay welding can be effective in producing compressive residual stresses at the pipe inner surface. This paper describes a computational model and its use in examining the effectiveness of the backlay welding process. The model has demonstrated an ability to predict weld-induced residual stresses for a variety of pipe sizes and welding conditions. Computational results for backlay welding are in agreement with residual stress data. The mechanisms causing residual stresses and the effect of the number of backlay weld layers on residual stresses are discussed.

scholarly journals Numerical Analysis of Axial Cyclic Behavior of FRP Retrofitted CHS Joints

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 648
Author(s):  
Mohammad Alembagheri ◽  
Maria Rashidi ◽  
Amin Yazdi ◽  
Bijan Samali
Keyword(s):  
Numerical Analysis ◽  
Welding Process ◽  
Axial Loading ◽  
Cyclic Behavior ◽  
Buckling Mode ◽  
Compression Load ◽  
Hollow Section ◽  
Plastic Failure ◽  
Frp Composite ◽  
Circular Hollow Section

This paper aims to numerically investigate the cyclic behavior of retrofitted and non-retrofitted circular hollow section (CHS) T-joints under axial loading. Different joints with varying ratios of brace to chord radius are studied. The effects of welding process on buckling instability of the joints in compression and the plastic failure in tension are considered. The finite element method is employed for numerical analysis, and the SAC protocol is considered as cyclic loading scheme. The CHS joints are retrofitted with different numbers of Fiber Reinforced Polymer (FRP) layers with varying orientation. The results show that the welding process significantly increases the plastic failure potential. The chord ovalization is the dominant common buckling mode under the compression load. However, it is possible to increase the energy dissipation of the joints by utilizing FRP composite through changing the buckling mode to the brace overall buckling.

Analysis on the Critical Buckling Stress in the TC4 Thin Plate Weldment

2011 ◽  
Vol 704-705 ◽  
pp. 1387-1392
Author(s):  
Xiu Ling Qi ◽  
Yong Zhang
Keyword(s):  
Compressive Stress ◽  
Thin Plate ◽  
Empirical Equation ◽  
Analytic Solution ◽  
Critical Value ◽  
Theoretical Formula ◽  
Buckling Stress ◽  
Longitudinal Residual Stress ◽  
Uneven Heating ◽  
Buckling Distortion

There exists a large amount of longitudinal tensile stress in the weld bead of the TC4 thin plate for the uneven heating of the welding thermal resource. Owing to the equilibrium of the internal stress, longitudinal compressive stress is also large on the edge of the thin plate. When the compressive stress is larger than the critical buckling stress, the buckling distortion can take place. Therefore, the value of the critical buckling stress is important to judge the distortion. Some theoretical formula and empirical equation can not give the suitable solution to the judge of the critical value of the certain TC4 thin plate weldment because of the difficulty in the analytic solution and difference in the feature of the material and boundary condition. Finite element method was utilized to estimate the value of the buckling stress in the thin plate. Based on the solution, the adjustment of welding longitudinal compressive stress model is done. Henceforth, the critical buckling stress can be determined by the method. Keywords: critical buckling stress, TC4 thin plate, welding longitudinal residual stress

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