scholarly journals Finite Element Analyses of Cold‐formed Stainless Steel Beams Subject to Shear

ce/papers ◽  
2019 ◽  
Vol 3 (3-4) ◽  
pp. 931-936
Author(s):  
Madhushan Dissanayake ◽  
Keerthan Poologanathan ◽  
Shanmuganathan Gunalan ◽  
Konstantinos Daniel Tsavdaridis ◽  
Brabha Nagaratnam
Author(s):  
Francis H. Ku ◽  
Trevor G. Hicks ◽  
William R. Mabe ◽  
Jason R. Miller

Two-dimensional (2D) and three-dimensional (3D) weld-induced residual stress finite element analyses have been performed for 2-inch Schedule 80 Type-304 stainless steel pipe sections joined by a multi-layer segmented-bead pipe weld. The analyses investigate the similarities and differences between the two modeling approaches in terms of residual stresses and axial shrinkage induced by the pipe weld. The 2D analyses are of axisymmetric behavior and evaluate two different pipe end constraints, namely fixed-fixed and fixed-free, while the 3D analysis approximates the non-axisymmetric segmented welding expected in production, with fixed-free pipe end constraints. Based on the results presented, the following conclusions can be drawn. The welding temperature contour results between the 2D and 3D analyses are very similar. Only the 3D analysis is capable of simulating the non-axisymmetric behavior of the segmented welding technique. The 2D analyses yield similar hoop residual stresses to the 3D analysis, and closely capture the maximum and minimum ID surface hoop residual stresses from the 3D analysis. The primary difference in ID surface residual stresses between the 2D fixed-fixed and 2D fixed-free constraints cases is the higher tensile axial stresses in the pipe outside of the weld region. The 2D analyses under-predict the maximum axial residual stress compared to the 3D analysis. The 2D ID surface residual stress results tend to bound the averaged 3D results. 2D axisymmetric modeling tends to significantly under-predict weld shrinkage. Axial weld shrinkage from 3D modeling is of the same magnitude as values measured in the laboratory on a prototypic mockup.


Author(s):  
Guiyi Wu ◽  
David Smith ◽  
David Tanner

Conventional approaches to assess fatigue under combined thermal and mechanical loading often utilize a fatigue design curve. In this paper models based on the physics and mechanics for the initiation and growth of fatigue cracks in stainless steel are first explained. The models are based on experimental evidence gathered for the initiation and growth of small cracks created during strain controlled laboratory tests. This evidence is then linked with data for the growth of large fatigue cracks in stainless steel. In the paper these models are coupled with finite element analyses to explore the fatigue initiation and growth of cracks in stainless steel pipes subjected to thermal cycling. It is assumed that the material behaviour is elastic-perfectly plastic, rate independent and fatigue occurs in air. The stress and strain fields for pipes subjected to a range of thermal loading conditions are explored. The fields are shown to be sensitive to parameters such as the Biot and Fourier numbers that include pipe dimensions, physical properties, dwell time and thermal conditions. Of particular interest is the temperature range and dwell time during thermal loading. Finite element analyses are then used to determine the stress and strain ranges created by thermal loading and these ranges are used in the crack initiation and growth models to estimate fatigue life.


2008 ◽  
Vol 580-582 ◽  
pp. 573-576 ◽  
Author(s):  
Jinya Katsuyama ◽  
Masahito Mochizuki ◽  
Hiroaki Mori ◽  
W. Asano ◽  
Gyu Baek An ◽  
...  

Recently, stress corrosion cracking (SCC) of primary piping of stainless steel has been observed. SCC is considered to initiate and progress at near the welding zone in butt-welded pipes, because of the tensile residual stress introduced by welding. In present work, three-dimensional and axisymmetric thermo-elastic-plastic finite element analyses have been carried out, in order to clarify the effect of geometrical and welding conditions on through-thickness residual stress. In particular, butt-welding joints of SUS316L pipes have been examined. The residual stress was simulated by three-dimensional and axisymmetric models and the results were compared and discussed in detail.


Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 786
Author(s):  
Fernando Ancio ◽  
Esperanza Rodriguez-Mayorga ◽  
Beatriz Hortigon

The use of stainless steel rebars to reinforce masonry structures has become established as an eminently efficient methodology. From among the numerous techniques available, bed-joint structural repointing and superficial reinforcement with rebars or meshes attached to surfaces have become widespread, thanks to the excellent results they have produced in recent decades. Both techniques imply the use of diameters less than 6 mm and thin coverings. This article deals with the characterization of the bonding behavior of the rebar under these special circumstances. To this end, several finite element analyses have been carried out to identify the possible relationships between pull-out forces in various situations. These models allow certain conclusions to be drawn regarding the influence of the thickness of covering, boundary conditions, and geometrical aspects of the rebars in bonding. Certain mathematical expressions that relate the various conclusions from this research are finally laid out.


ce/papers ◽  
2019 ◽  
Vol 3 (3-4) ◽  
pp. 907-912
Author(s):  
Ishqy Fareed ◽  
Wanniarachchi Somadasa ◽  
Keerthan Poologanathan ◽  
Shanmuganathan Gunalan ◽  
Marco Corradi ◽  
...  

2018 ◽  
Author(s):  
Miguel Abambres

Original Generalized Beam Theory (GBT) formulations for elastoplastic first and second order (postbuckling) analyses of thin-walled members are proposed, based on the J2 theory with associated flow rule, and valid for (i) arbitrary residual stress and geometric imperfection distributions, (ii) non-linear isotropic materials (e.g., carbon/stainless steel), and (iii) arbitrary deformation patterns (e.g., global, local, distortional, shear). The cross-section analysis is based on the formulation by Silva (2013), but adopts five types of nodal degrees of freedom (d.o.f.) – one of them (warping rotation) is an innovation of present work and allows the use of cubic polynomials (instead of linear functions) to approximate the warping profiles in each sub-plate. The formulations are validated by presenting various illustrative examples involving beams and columns characterized by several cross-section types (open, closed, (un) branched), materials (bi-linear or non-linear – e.g., stainless steel) and boundary conditions. The GBT results (equilibrium paths, stress/displacement distributions and collapse mechanisms) are validated by comparison with those obtained from shell finite element analyses. It is observed that the results are globally very similar with only 9% and 21% (1st and 2nd order) of the d.o.f. numbers required by the shell finite element models. Moreover, the GBT unique modal nature is highlighted by means of modal participation diagrams and amplitude functions, as well as analyses based on different deformation mode sets, providing an in-depth insight on the member behavioural mechanics in both elastic and inelastic regimes.


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