Modelling and probabilistic study of the residual stress of cold-formed hollow steel sections

2017 ◽  
Vol 150 ◽  
pp. 986-995 ◽  
Author(s):  
Wenyu Liu ◽  
Kim J.R. Rasmussen ◽  
Hao Zhang
1980 ◽  
Vol 102 (3) ◽  
pp. 323-331 ◽  
Author(s):  
E. F. Rybicki ◽  
R. B. Stonesifer

An analysis procedure for computing residual stresses due to weld repairs of heavy steel sections is described and illustrated. The model has several unique features for weld repair applications. These include a simple formula for computing temperatures in and near the repair region, a method for economically modeling the application of hundreds of weld passes typically required in repairs, and a method by which the basically two-dimensional residual stress analysis model can be inexpensively modified to incorporate some three-dimensional effects. Laboratory data for residual stresses due to the weld repair of a flat plate and computed values for a curved plate are compared. Good qualitative agreement is found. Next, the computational model is used to predict residual stresses due to a weld repair in one of the Heavy Section Steel Technology Intermediate Test Vessels. Residual stress data available for this vessel are compared with predicted values of residual stress. There is good agreement between the computed values and residual stress data for regions outside of the weld repair. A discussion of the overall agreement is given. This study demonstrates that it is economically feasible to predict the complex behavior of weld repair residual stresses.


2010 ◽  
Vol 163-167 ◽  
pp. 346-350
Author(s):  
Hua Chen Liu ◽  
Yao Jie Guo

In calculating the reliable capacity of carrying load of cold-formed thin-walled steel members, there has not yet been a proper method which directly takes into account the impact of the residual stress. Through the research of residual stress, models close to the actual situation are established. Based on the ultimate load criterion, considering both cold-formed residual stress and initial out-of-straightness, the whole stability of axially loaded compression member of cold-formed thin-walled crimping angle steel and channel steel are analyzed using FEM. Based on a lot of FEA numerical results obtained, the φ-λ curves of different kinds of sections and size are obtained. Finally, φ-λ curve that reflects the fact can be obtained. By comparing the curve with the code and results of experience, it is proposed that the stability coefficient φ of small slenderness member of the code should be increased appropriately.


Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5378
Author(s):  
Ayad Mutafi ◽  
Noorfaizal Yidris ◽  
Seyed Saeid Rahimian Koloor ◽  
Michal Petrů

Stainless steels are increasingly used in construction today, especially in harsh environments, in which steel corrosion commonly occurs. Cold-formed stainless steel structures are currently increasing in popularity because of its efficiency in load-bearing capacity and its appealing architectural appearance. Cold-rolling and press-braking are the cold-working processes used in the forming of stainless steel sections. Press braking can produce large cross-sections from thin to thick-walled sections compared to cold-rolling. Cold-forming in press-braked sections significantly affect member behaviour and joints; therefore, they have attained great attention from many researchers to initiate investigations on those effects. This paper examines the behaviour of residual stress distribution of stainless steel press-braked sections by implementing three-dimensional finite element (3D-FE) technique. The study proposed a full finite element procedure to predict the residual stresses starting from coiling-uncoiling to press-braking. This work considered material anisotropy to examine its effect on the residual stress distribution. The technique adopted was compared with different finite element techniques in the literature. This study also provided a parametric study for three corner radius-to-thickness ratios looking at the through-thickness residual stress distribution of four stainless steels (i.e., ferritic, austenitic, duplex, lean duplex) in which have their own chemical composition. In conclusion, the comparison showed that the adopted technique provides a detailed prediction of residual stress distribution. The influence of geometrical aspects is more pronounced than the material properties. Neglecting the material anisotropy shows higher shifting in the neutral axis. The parametric study showed that all stainless steel types have the same stress through-thickness distribution. Moreover, R/t ratios’ effect is insignificant in all transverse residual stress distributions, but a slight change to R/t ratios can affect the longitudinal residual stress distribution.


2014 ◽  
Vol 79 ◽  
pp. 38-51 ◽  
Author(s):  
H.X. Yuan ◽  
Y.Q. Wang ◽  
Y.J. Shi ◽  
L. Gardner

2020 ◽  
Vol 168 ◽  
pp. 105994 ◽  
Author(s):  
Baofeng Zheng ◽  
Sen Yang ◽  
Xin Jin ◽  
Ganping Shu ◽  
Shutong Dong ◽  
...  

Author(s):  
Zelalem Abathun Mehari ◽  
Jingtao Han

With the growing demand for rectangular and square hollow steel sections in the last few decades, the cold roll forming process has become a widely acknowledged hollow sections manufacturing method; however, residual stress generated during the roll forming process is one of the primary concerns on roll-formed products. In this regard, several researchers have conducted numerical and experimental investigations of residual stress distributions on roll-formed steel sections. However, most of the studies found in the literature have been confined to the measurement of residual surface stresses. On the other hand, experimental studies conducted on fatigue and load-carrying capacity of hollow structural steels have shown that there is indeed a simple relation between the through-thickness residual stress distributions and mechanical properties of structures. Thus, this paper employed a proper numerical modelling procedure using LS-DYNA’s finite element code to explore through-thickness residual stress distributions generated during the roll forming process of rectangular and square hollow steel sections from different material grades. Moreover, a small-scale parametric study was conducted to explore the effects of the partial heating roll forming method on through-the-thickness residual stress distributions to satisfy the growing demand for residual stress-free roll-formed products.


Author(s):  
J. Fang ◽  
H. M. Chan ◽  
M. P. Harmer

It was Niihara et al. who first discovered that the fracture strength of Al2O3 can be increased by incorporating as little as 5 vol.% of nano-size SiC particles (>1000 MPa), and that the strength would be improved further by a simple annealing procedure (>1500 MPa). This discovery has stimulated intense interest on Al2O3/SiC nanocomposites. Recent indentation studies by Fang et al. have shown that residual stress relief was more difficult in the nanocomposite than in pure Al2O3. In the present work, TEM was employed to investigate the microscopic mechanism(s) for the difference in the residual stress recovery in these two materials.Bulk samples of hot-pressed single phase Al2O3, and Al2O3 containing 5 vol.% 0.15 μm SiC particles were simultaneously polished with 15 μm diamond compound. Each sample was cut into two pieces, one of which was subsequently annealed at 1300° for 2 hours in flowing argon. Disks of 3 mm in diameter were cut from bulk samples.


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