Flexural Buckling of Columns Strengthened under Load

2015 ◽  
Vol 1122 ◽  
pp. 257-260
Author(s):  
Martin Vild ◽  
Miroslav Bajer
Keyword(s):  
Cross Section ◽  
Transient Analysis ◽  
Base Material ◽  
Reduction Factor ◽  
Steel Plates ◽  
Welded Steel ◽  
Compression Load ◽  
Flexural Buckling ◽  
Ultimate Resistance ◽  
Element Study

This paper refers to behaviour and capacity of axially loaded columns strengthened under load using welded steel plates. This method of strengthening is fast, simple and widely used but no universal and reliable analytical solution has been presented yet. In the paper, focus is put on flexural buckling. The approach using cross-section properties of strengthened member and the modified buckling reduction factor was used to calculate the ultimate resistance. In buckling theory, the resistance of column subjected to compression load is reached when the most stressed fibres start to yield. However, some researchers allow certain amount of yielding for base material of columns strengthened under load. In the paper, the new modified buckling reduction factor based on Eurocodes is derived. Two types of column strengthening under various preload magnitudes are investigated using finite element study in ANSYS code and transient analysis type. Birth and death of elements is used to simulate strengthening welded plates. The results are compared with analytical solutions.

scholarly journals Experimental Study on Laser-MIG Hybrid Welding of Thick High-Mn Steel Plate for Cryogenic Tank Production

2021 ◽  
Vol 9 (6) ◽  
pp. 604
Author(s):  
Du-Song Kim ◽  
Hee-Keun Lee ◽  
Woo-Jae Seong ◽  
Kwang-Hyeon Lee ◽  
Hee-Seon Bang
Keyword(s):  
Low Temperature ◽  
Yield Strength ◽  
Steel Plate ◽  
Weld Zone ◽  
Base Material ◽  
Hardness Test ◽  
Steel Plates ◽  
Hybrid Welding ◽  
Temperature Impact ◽  
Mn Steel

The International Maritime Organization has recently updated the ship emission standards to reduce atmospheric contamination. One technique for reducing emissions involves using liquefied natural gas (LNG). The tanks used for the transport and storage of LNG must have very low thermal expansion and high cryogenic toughness. For excellent cryogenic properties, high-Mn steel with a complete austenitic structure is used to design these tanks. We aim to determine the optimum welding conditions for performing Laser-MIG (Metal Inert Gas) hybrid welding through the MIG leading and laser following processes. A welding speed of 100 cm/min was used for welding a 15 mm thick high-Mn steel plate. The welding performance was evaluated through mechanical property tests (tensile and yield strength, low-temperature impact, hardness) of the welded joints after performing the experiment. As a result, it was confirmed that the tensile strength was slightly less than 818.4 MPa, and the yield strength was 30% higher than base material. The low-temperature impact values were equal to or greater than 58 J at all locations in the weld zone. The hardness test confirmed that the hardness did not exceed 292 HV. The results of this study indicate that it is possible to use laser-MIG hybrid welding on thick high-Mn steel plates.

Fatigue Behaviour of Friction Stir Welded Steel Joints

2014 ◽  
Vol 891-892 ◽  
pp. 1488-1493 ◽  
Author(s):  
José Azevedo ◽  
Virgínia Infante ◽  
Luisa Quintino ◽  
Jorge dos Santos
Keyword(s):  
Base Material ◽  
Welding Process ◽  
Steel Structures ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Welded Steel ◽  
Shipbuilding Industry ◽  
Friction Stir ◽  
Steel Joints

The development and application of friction stir welding (FSW) technology in steel structures in the shipbuilding industry provide an effective tool of achieving superior joint integrity especially where reliability and damage tolerance are of major concerns. Since the shipbuilding components are inevitably subjected to dynamic or cyclic stresses in services, the fatigue properties of the friction stir welded joints must be properly evaluated to ensure the safety and longevity. This research intends to fulfill a clear knowledge gap that exists nowadays and, as such, it is dedicated to the study of welded steel shipbuilding joints in GL-A36 steel, with 4 mm thick. The fatigue resistance of base material and four plates in as-welded condition (using several different parameters, tools and pre-welding conditions) were investigated. The joints culminate globally with defect-free welds, from which tensile, microhardness, and fatigue analyses were performed. The fatigue tests were carried out with a constant amplitude loading, a stress ratio of R=0.1 and frequency between 100 and 120 Hz. The experimental results show the quality of the welding process applied to steel GL-A36 which is reflected in the mechanical properties of joints tested.

Aspects Regarding the Achievement of Vertical Welding Joints

2015 ◽  
Vol 1128 ◽  
pp. 254-260 ◽  
Author(s):  
Radu Cristian Seculin ◽  
Barna Fazakas ◽  
Teodor Machedon Pisu ◽  
Mihai Alin Pop
Keyword(s):  
Point Of View ◽  
Steel Plates ◽  
Welding Parameters ◽  
Welding Wire ◽  
Oscillation System ◽  
Welded Steel ◽  
Welding Torch ◽  
Welding Joints ◽  
Protective Gas ◽  
Welding Procedure

The vertical MAG welding procedure is a difficult position to be executed because the trend of the molten bath flowing. This article aims to present the achievement of vertical welding joints with a linear device with a radial oscillation system that should achieve automatic vertical welds and the correlation of the welding parameters with the movement of the welding torch in order to obtain these, using the MAG procedure, protective gas M 21 (82% argon + 18% CO2), welding wire SG2, the material of the welded pieces S 355 JR. Samples will be cut from the welded steel plates and they will be characterized from the mechanical point of view (hardness, microstructure and macrostructure).

Mechanical Behaviour of Welded Joints Achieved by Multi-Wire Submerged Arc Welding

2017 ◽  
Vol 1143 ◽  
pp. 52-57
Author(s):  
Elena Scutelnicu ◽  
Carmen Catalina Rusu ◽  
Bogdan Georgescu ◽  
Octavian Mircea ◽  
Melat Bormambet
Keyword(s):  
Mechanical Behaviour ◽  
Welded Joints ◽  
Arc Welding ◽  
Base Material ◽  
High Strength ◽  
Submerged Arc Welding ◽  
Steel Plates ◽  
Wire Saw ◽  
Api 5L X70 Steel ◽  
Submerged Arc

The paper addresses the development of advanced welding technologies with two and three solid wires for joining of HSLA API-5l X70 (High-strength low-alloy) steel plates with thickness of 19.1 mm. The experiments were performed using a multi-wire Submerged Arc Welding (SAW) system that was developed for welding of steels with solid, tubular and cold wires, in different combinations. The main goal of the research was to assess the mechanical performances of the welded joints achieved by multi-wire SAW technology and then to compare them with the single wire variant, as reference system. The welded samples were firstly subjected to NDT control by examinations with liquid penetrant, magnetic particle, ultrasonic and gamma radiation, with the aim of detecting the specimens with flaws and afterwards to reconsider and redesign the corresponding Welding Procedure Specifications (WPS). The defect-free welded samples were subjected to tensile, Charpy V-notch impact and bending testing in order to analyse and report the mechanical behaviour of API-5l X70 steel during multi-wire SAW process. The experimental results were processed and comparatively discussed. The challenge of the investigation was to find the appropriate welding technology which responds simultaneously to the criteria of quality and productivity. Further research on metallurgical behaviour of the base material will be developed, in order to conclude the complete image of the SAW process effects and to understand how the multi-wire technologies affect the mechanical and metallurgical characteristics of the API-5L X70 steel used in pipelines fabrication.

scholarly journals Effect of Residual Stresses on the Elastoplastic Behavior of Welded Steel Plates

2020 ◽  
Vol 8 (9) ◽  
pp. 702
Author(s):  
José Manuel Gordo
Keyword(s):  
Residual Stresses ◽  
Bending Strength ◽  
Steel Plates ◽  
Finite Elements Analysis ◽  
Elastoplastic Behavior ◽  
Welded Steel ◽  
Plate Elements ◽  
Tension And Compression ◽  
Free Case ◽  
Range Of Variation

A robust methodology to simulate virtually the residual stresses pattern in welded steel plates is presented. The methodology is applied to the structural analysis of typical welded plates belonging to ship structures, and the effect of residual stresses on the elastoplastic behavior of plates loaded axially is analyzed in comparison to the residual stress free case, both for tension and compression and including initial imperfections. Residual stresses affect in different manner plates with different geometries; thus a parametric study is performed covering the usual range of variation of the most important plate parameters that control the strength of the plates, more precisely the slenderness and the aspect ratio. The results from finite elements analysis are compared with codes and most established formulations and recommendations of applicability in the prediction of load-shortening curves for hull’s bending strength evaluation, ultimate strength and ultimate strain of plate elements are made.

scholarly journals Calculation of Axial Compression Capacity for Square Columns Strengthened with HPFL and BSP

2016 ◽  
Vol 2016 ◽  
pp. 1-11
Author(s):  
Hua Huang ◽  
Kailin Xi ◽  
Yu Zhang ◽  
Jinghui Shi ◽  
Boquan Liu
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
High Performance ◽  
Reduction Factor ◽  
Steel Plates ◽  
Strength Reduction Factor ◽  
Compression Performance ◽  
Load Carrying ◽  
Calculation Results ◽  
Primary Damage

The load carrying capacity and failure mechanism of 8 square columns strengthened with high-performance ferrocement laminate (HPFL) and bonded steel plates (BSP) were analyzed on the basis of experiments on the axial compression performance of these columns. Results show that the reinforcing layer worked together with the original columns as a whole, and the load-bearing capacity significantly increased. When failure of the strengthened column occurred, the mortar and concrete were crushed and bulged outward in the middle of the columns, the angle bars and longitudinal steel bars buckled, and some stirrups were pulled out. The chamfering of angle bar momentously affected the primary damage of steel strand. The values of the strength reduction factor and pressure effective utilization coefficient of the mortar were suggested. Based on the experiments and existing tests of 35 columns strengthened with HPFL, equations for the axial compression bearing capacity were proposed and all calculation results agreed well with testing results. Therefore, the calculation method could be used in the capacity design of axial compression strengthened columns.

Design of Laterally Loaded Plating—Uniform Pressure Loads

1981 ◽  
Vol 25 (02) ◽  
pp. 77-89
Author(s):  
Owen F. Hughes
Keyword(s):  
High Speed ◽  
Lateral Pressure ◽  
Experimental Studies ◽  
Steel Plates ◽  
Subsequent Paper ◽  
Rigid Plastic ◽  
Welded Steel ◽  
High Speed Impact ◽  
Laterally Loaded ◽  
Good Agreement

An explicit formula is presented for the design of welded steel plates subjected to uniform lateral pressure, on the basis of a designer-specified level of acceptable permanent set, including that due to welding. The formula is derived from a combination of theoretical and experimental studies and shows good agreement with experimental results. For the convenience of designers the formula is also given in the form of design curves. The paper also delineates the areas of application of this and other formulas for laterally loaded plating. In brief, the paper shows that for static and quasistatic loads the formula derived herein is more accurate than formulas based on either the pseudo-elastic or the rigid-plastic approach. As the load becomes more dynamic the rigid-plastic approach becomes more appropriate, and for high-speed impact loads the rigid-plastic approach is best. For quasistatic loads, such as slamming, the formula presented herein is somewhat conservative while the rigid-plastic formulas are somewhat optimistic. A similar formula for concentrated loads (such as wheel loads) will be presented in a subsequent paper.

scholarly journals Behavior of reinforced concrete columns strenghtened by partial jacketing

2016 ◽  
Vol 9 (1) ◽  
pp. 1-21 ◽  
Author(s):  
D. B. FERREIRA ◽  
R. B. GOMES ◽  
A. L. CARVALHO ◽  
G. N. GUIMARÃES
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Concrete Columns ◽  
The Other ◽  
Self Compacting Concrete ◽  
Reinforced Concrete Columns ◽  
Compressive Stresses ◽  
Concrete Layer ◽  
Ultimate Resistance

This article presents the study of reinforced concrete columns strengthened using a partial jacket consisting of a 35mm self-compacting concrete layer added to its most compressed face and tested in combined compression and uniaxial bending until rupture. Wedge bolt connectors were used to increase bond at the interface between the two concrete layers of different ages. Seven 2000 mm long columns were tested. Two columns were cast monolithically and named PO (original column) e PR (reference column). The other five columns were strengthened using a new 35 mm thick self-compacting concrete layer attached to the column face subjected to highest compressive stresses. Column PO had a 120mm by 250 mm rectangular cross section and other columns had a 155 mm by 250mm cross section after the strengthening procedure. Results show that the ultimate resistance of the strengthened columns was more than three times the ultimate resistance of the original column PO, indicating the effectiveness of the strengthening procedure. Detachment of the new concrete layer with concrete crushing and steel yielding occurred in the strengthened columns.

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