Column behaviour of cold-formed hollow structural steel shapes

1983 ◽  
Vol 10 (1) ◽  
pp. 125-141 ◽  
Author(s):  
T. A. Davison ◽  
P. C. Birkemoe
Keyword(s):  
Residual Stress ◽  
Theoretical Model ◽  
Structural Steel ◽  
Experimental Tests ◽  
Theoretical Research ◽  
Relative Importance ◽  
Cross Sectional ◽  
Heat Treated ◽  
Steel Shapes ◽  
Sectional Parameters

This paper presents a theoretical model describing the column behaviour of cold-formed heat-treated and non-heat-treated hollow structural steel (HSS) shapes. Member cross-sectional parameters in the form of residual stress and yield strength gradients as well as the member initial crookedness are incorporated into the column model. The parameter magnitudes used and their dispositions throughout the model are based on current experimental and theoretical research. The effect and relative importance of these parameters in determining the theoretical column strength is illustrated. The adequacy of the theoretical model in determining HSS column strength is shown by comparing it with the results of experimental tests conducted on full-sized HSS specimens. Finally, design curves for each of the HSS types studied are recommended.

scholarly journals Concept for controlled adjustment of residual stress states in semi-finished products by gradation extrusion

2021 ◽  
Author(s):  
René Selbmann ◽  
Markus Baumann ◽  
Mateus Dobecki ◽  
Markus Bergmann ◽  
Verena Kräusel ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Experimental Tests ◽  
Residual Stress Distribution ◽  
Forming Process ◽  
Compressive Stresses ◽  
Energy Consuming ◽  
Stress States ◽  
Set Up ◽  
Time And Energy

AbstractThe residual stress distribution in extruded components and wires after a conventional forming process is frequently unfavourable for subsequent processes, such as bending operations. High tensile residual stresses typically occur near the surface of the wire and thus limit further processability of the material. Additional heat treatment operations or shot peening are often inserted to influence the residual stress distribution in the material after conventional manufacturing. This is time and energy consuming. The research presented in this paper contains an approach to influence the residual stress distribution by modifying the forming process for wire-like applications. The aim of this process is to lower the resulting tensile stress levels near the surface or even to generate compressive stresses. To achieve these residual compressive stresses, special forming elements are integrated in the dies. These modifications in the forming zone have a significant influence on process properties, such as degree of deformation and deformation direction, but typically have no influence on the diameter of the product geometry. In the present paper, the theoretical approach is described, as well as the model set-up, the FE-simulation and the results of the experimental tests. The characterization of the residual stress states in the specimen was carried out by X-ray diffraction using the sin2Ψ method.

Investigation on penetration model of shaped charge jet in water

2016 ◽  
Vol 30 (02) ◽  
pp. 1550268 ◽  
Author(s):  
Jinwei Shi ◽  
Xingbai Luo ◽  
Jinming Li ◽  
Jianwei Jiang
Keyword(s):  
Numerical Simulation ◽  
Theoretical Model ◽  
Model Simulation ◽  
Theoretical Models ◽  
Theoretical Research ◽  
Water Medium ◽  
Simulation Results ◽  
Jet Penetration ◽  
The Impact ◽  
Penetration Velocity

To analyze the process of jet penetration in water medium quantitatively, the properties of jet penetration spaced target with water interlayer were studied through test and numerical simulation. Two theoretical models of jet penetration in water were proposed. The theoretical model 1 was established considering the impact of the shock wave, combined with the shock equation Rankine–Hugoniot and the virtual origin calculation method. The theoretical model 2 was obtained by fitting theoretical analysis and numerical simulation results. The effectiveness and universality of the two theoretical models were compared through the numerical simulation results. Both the models can reflect the relationship between the penetration velocity and the penetration distance in water well, and both the deviation and stability of theoretical model 1 are better than 2, the lower penetration velocity, and the larger deviation of the theoretical model 2. Therefore, the theoretical model 1 can reflect the properties of jet penetration in water effectively, and provide the reference of model simulation and theoretical research.

Prediction for Post-Forming Spring Back of CICC in the Superconducting Tokamak Fusion Device via Virtual Manufacturing

2000 ◽  
Author(s):  
Yeong Sung Suh ◽  
Jong Sung Ahn ◽  
Sun Woong Choi ◽  
Hyun Ki Park ◽  
Yong Jin Kim ◽  
...  
Keyword(s):  
Residual Stress ◽  
Cross Section ◽  
Virtual Manufacturing ◽  
Von Mises Stress ◽  
Radius Of Curvature ◽  
Spring Back ◽  
Cross Sectional ◽  
Fusion Device ◽  
Roll Bending ◽  
Superconducting Tokamak

Abstract To construct the CICC for the superconducting Tokamak fusion device, the 3-roll bending, that inherently has a difficulty to form the coil with accurate radius of curvature, is used for continuous winding. In order to obtain precise dimension, a trial-an-error operation is inevitable. To reduce the effort of tryout, a relation between travel of the bending roller and spring back displacement was obtained via virtual manufacturing. The radius of CICC after forming was expressed as a function of the bend-roll travel. Next, the variation of the CICC cross-section (reduction of the conduit cross-section) was investigated during the first turn and during conduit bending with largest curvature. With largest curvature, the cross-sectional area was not much reduced. Finally, the residual stress on the CICC before roll bending was measured in order to examine the influence of the original residual stress on the final deformation behavior. The principal stress and von Mises stress were measured at the surface of CICC using specially designed strain gauge. The measured values were considered in the virtual forming. The results indicate that the residual stresses generated during the fabrication of the CICC (before coiling) do not have much influence on the final stress state.

scholarly journals Cross-Sectional Mapping of Residual Stresses by Measuring the Surface Contour After a Cut

2000 ◽  
Vol 123 (2) ◽  
pp. 162-168 ◽  
Author(s):  
M. B. Prime
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Measurement ◽  
Superposition Principle ◽  
New Method ◽  
Contour Method ◽  
Stress Profile ◽  
Relaxation Methods ◽  
Cross Sectional ◽  
Residual Stress Profile

A powerful new method for residual stress measurement is presented. A part is cut in two, and the contour, or profile, of the resulting new surface is measured to determine the displacements caused by release of the residual stresses. Analytically, for example using a finite element model, the opposite of the measured contour is applied to the surface as a displacement boundary condition. By Bueckner’s superposition principle, this calculation gives the original residual stresses normal to the plane of the cut. This “contour method” is more powerful than other relaxation methods because it can determine an arbitrary cross-sectional area map of residual stress, yet more simple because the stresses can be determined directly from the data without a tedious inversion technique. The new method is verified with a numerical simulation, then experimentally validated on a steel beam with a known residual stress profile.

Modelling of Dilution Effects on Microstructure and Residual Stress in a Multi-Pass Weldment

2018 ◽  
Author(s):  
Yongle Sun ◽  
C. J. Hamelin ◽  
M. C. Smith ◽  
A. N. Vasileiou ◽  
T. F. Flint ◽  
...  
Keyword(s):  
Residual Stress ◽  
Weld Metal ◽  
Phase Distribution ◽  
Measurement Data ◽  
Base Material ◽  
Cross Sectional ◽  
Gas Tungsten Arc ◽  
Compressive Stresses ◽  
Thermal Solution ◽  
Dilution Effects

Three-pass gas tungsten arc welding in a 20-mm thick SA508 steel plate is modelled using a sequentially coupled thermal-metallurgical-mechanical model. The dilution for each pass is estimated as the proportion of base material in the weld metal, based on an analysis of the cross-sectional area of each fusion zone. The thermal solution of the weld model is validated using thermocouple measurement data and cross-weld macrographs. The predicted microstructure is qualitatively compared with that observed in cross-weld optical micrographs. The measured hardness distribution is used to quantitatively validate the post-weld ferritic phase distribution (e.g. the ferrite, bainite and martensite fractions), based on a hardness-microstructure correlation. The predicted residual stresses are compared with those measured by neutron diffraction. The results show that dilution significantly influences the metallurgical and mechanical properties of weld metal (either as-deposited or reheated), and its consideration notably improves microstructure and residual stress predictions for a multi-pass steel weldment. For the weldment considered, an increase in dilution promotes the formation of martensite, enhances the hardness and leads to lower tensile stresses (or higher compressive stresses) in the weld metal. Such behaviour arises due to the higher hardenability of the base material, coupled with delayed austenite decomposition on cooling.

scholarly journals Predicting How Crack Tip Residual Stresses Influence Brittle Fracture

2002 ◽  
Author(s):  
Saeid Hadidimoud ◽  
Ali Mirzaee-Sisan ◽  
Chris E. Truman ◽  
David J. Smith
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Experimental Studies ◽  
Crack Tip ◽  
Distribution Model ◽  
Relative Importance ◽  
Local Approach ◽  
Weibull Parameters ◽  
Experimental Scatter ◽  
Crack Tip Blunting

A probability distribution model, based on the local approach to fracture, has been developed and used for estimating cleavage fracture following prior loading (or warm pre-stressing) in two ferritic steels. Although there are many experimental studies it is not clear from these studies whether the generation of local residual stress and/or crack tip blunting as a result of prior loading contribute to the enhancement in toughness. We first identify the Weibull parameters required to match the experimental scatter in lower shelf toughness of the candidate steels. Second we use these parameters in finite element simulations of prior loading on the upper shelf followed by unloading and cooling to lower shelf temperatures to determine the probability of failure. The predictions are consistent with experimental scatter in toughness following WPS and provide a means of determining the relative importance of the crack tip residual stresses and crack tip blunting. We demonstrate that for our steels the crack tip residual stress is the pivotal feature in improving the fracture toughness following WPS. The paper finally discusses these results in the context of the non-uniqueness and the sensitivity of the Weibull parameters.

Residual Stress at Fatigue Fracture Surface of Heat Treated High Strength Steels

1979 ◽  
pp. 227-232 ◽  
Author(s):  
Atsutomo Komine ◽  
Hideo Ueda ◽  
Eisuke Nakanishi ◽  
Shotaro Araki ◽  
Kazuo Taguchi
Keyword(s):  
Residual Stress ◽  
Fracture Surface ◽  
Fatigue Fracture ◽  
High Strength Steels ◽  
High Strength ◽  
Fatigue Fracture Surface ◽  
Heat Treated

On the Mechanics of Residual Stresses in Girth Welds

2006 ◽  
Vol 129 (3) ◽  
pp. 345-354 ◽  
Author(s):  
P. Dong
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Relative Importance ◽  
Stress Distributions ◽  
Unified Framework ◽  
Joint Geometry ◽  
Weld Residual Stress ◽  
Girth Welds ◽  
Welding Procedure

In this paper, some of the important controlling parameters governing weld residual stress distributions are presented for girth welds in pipe and vessel components, based on a large number of residual stress solutions available to date. The focus is placed upon the understanding of some of the overall characteristics in through-wall residual stress distributions and their generalization for vessel and pipe girth welds. In doing so, a unified framework for prescribing residual stress distributions is outlined for fitness-for-service assessment of vessel and pipe girth welds. The effects of various joint geometry and welding procedure parameters on through thickness residual stress distributions are also demonstrated in the order of their relative importance.

scholarly journals Stiffness of Concrete-Filled Thin-Walled Steel Tubular Slender Columns

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Alireza Bahrami ◽  
Ali Mahmoudi Kouhi
Keyword(s):  
Uniform Distribution ◽  
Experimental Tests ◽  
Simulation Method ◽  
Steel Tube ◽  
Initial Stiffness ◽  
Cross Sectional ◽  
Circular Column ◽  
Finite Element Software ◽  
Thin Walled ◽  
Slender Columns

Abstract Concrete-filled thin-walled steel tubular slender columns are studied in this paper to evaluate their stiffness. The slender columns have various steel tube thicknesses, length/diameter (width) ratios, and concrete compressive strengths. The columns are loaded by axial and eccentric loads. Two experimental tests of the slender and stub columns are described. Also, the finite element software ABAQUS is utilised to simulate and analyse the columns. The tested columns are simulated taking into account all their features in the tests to verify the simulation of the columns. The simulation results are compared with the tests results which reveal that good agreements exist between them. Thus, the proposed simulation method of the columns is verified. In order to assess the stiffness of the columns under different conditions, various load eccentricities (0 mm, 25 mm, and 50 mm), cross-sectional configurations (circular, rectangular, and square), and steel tube thicknesses (2 mm, 3.35 mm, and 5 mm) are adopted for the developed columns. The columns are simulated and analysed based on the verified simulation method considering the mentioned conditions. As a conclusion, the stiffness of the columns is generally reduced by the increase of the load eccentricity from 0 mm to 25 mm and 50 mm. Further, more uniform distribution of the stiffness is witnessed for the columns with lower eccentricities. In addition, the enhancement of the load eccentricity increased the reduction slope of the stiffness graph for the columns. Although the initial stiffness of the circular column is slightly lower than the rectangular and square columns, the stiffness has more uniform distribution which is preferred. Larger stiffness is achieved for the columns by increasing the steel tube thickness from 2 mm to 3.35 mm and 5 mm.

Softening of heat treated structural steel

1964 ◽  
Vol 6 (8) ◽  
pp. 516-518
Author(s):  
A. Ya. Brodskii ◽  
N. V. Tolmacheva ◽  
P. Rombari
Keyword(s):  
Structural Steel ◽  
Heat Treated
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