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Ou Zhao - One of the best experts on this subject based on the ideXlab platform.
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Experimental and numerical studies of pin-ended press-braked S960 ultra-high strength steel Channel Section columns
Engineering Structures, 2020Co-Authors: Fangying Wang, Yating Liang, Ou ZhaoAbstract:Abstract Grade S960 ultra-high strength steel is receiving increasing attention owing to its excellent strength-to-weight ratio. However, its application in construction engineering is rather limited due to the lack of adequate design rules, as the current established codes in Europe, North America and Australia/New Zealand only cover the design of steel components with material grades up to S700 (or S690). This prompts investigations into different types of S960 UHSS structural components and development of accurate and efficient design rules for them. The present paper focuses on press-braked S960 UHSS Channel Section columns prone to flexural buckling about the minor principal axes, with their behaviour and resistances thoroughly examined through experiments and numerical modelling. An experimental programme was firstly performed on two non-slender press-braked Channel Sections, with five column specimens of varying member lengths employed for each cross-Section, and included initial global and local geometric imperfection measurements and pin-ended column tests about the minor principal axes. This was followed by a parallel numerical modelling programme, where finite element (FE) models were developed to simulate the experimental results and afterwards adopted to perform a parametric study to generate additional numerical data over a broader spectrum of cross-Section dimensions and member lengths. It is worth noting that there were two orientations associated with minor-axis flexural buckling of press-braked S960 UHSS Channel Section columns, namely ‘C’ orientation (indicating that columns buckled towards the webs) and ‘reverse C’ orientation (indicating that columns buckled towards the flange tips), and both of the two types of failure modes were carefully examined in the present study. It was found that Channel Section columns failing by flexural buckling in the ‘reverse C’ orientation generally exhibited superior resistances relative to their counterparts with failure in the ‘C’ orientation. The experimental and numerical data were also used to assess the applicability of the codified provisions for press-braked S700 (or S690) Channel Section columns failing by flexural buckling about the minor principal axes to the design of their S960 counterparts. The assessment results indicated that (i) the existing European code leads to overall conservative and scattered design flexural buckling resistances, especially for those relatively short and intermediate press-braked S960 UHSS Channel Section columns with failure in the ‘reverse C’ orientation, and (ii) the North American specification and Australian/New Zealand standard result in a higher degree of design accuracy and consistency than the European code, but with many over-predicted flexural buckling resistances for press-braked S960 UHSS Channel Section short and intermediate columns failing in the ‘C’ orientation.
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Experimental and numerical studies of press-braked S690 high strength steel Channel Section beams
Thin-walled Structures, 2020Co-Authors: Lulu Zhang, Fangying Wang, Yating Liang, Ou ZhaoAbstract:Abstract The present paper describes an in-depth experimental and numerical investigation into the flexural responses and strengths of press-braked S690 high strength steel Channel Section beams bent about the minor principal axes in both the ‘u’ and ‘n’ orientations. The experimental study was performed on eight press-braked Channel Sections, and comprised twenty-four material flat and corner coupon tests, initial local geometric imperfection measurements, and twelve beam tests in the four-point bending configuration. This was followed by a complementary numerical modelling programme, where finite element models were firstly developed and validated against the test results and afterwards adopted for performing parametric studies to obtain an additional numerical data bank over a wide variety of cross-Section geometric sizes. The acquired test and numerical data were then employed to evaluate the applicability of the Eurocode slenderness limits for welded and hot-rolled internal webs (in compression) and outstand flanges (in stress gradients) to their press-braked counterparts, revealing that the Eurocode slenderness limits can be safely extended to cover the classifications of plate elements and cross-Sections of press-braked S690 high strength steel Channel Section beams. Evaluation of the accuracy of the cross-Section flexural strengths predicted from various design codes established in Europe, North America and Australia/New Zealand was also made, based on the test and numerical data. The results of the quantitative evaluation generally revealed that (i) all the examined design codes lead to overall conservative and scattered predicted cross-Section flexural strengths for press-braked S690 high strength steel Channel Section beams, and (ii) the European code results in more precise design flexural strengths for beams with relatively stocky Channel Sections, but less accurate strength predictions for beams with relatively slender Channel Sections, compared to the North American and Australian/New Zealand standards.
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Testing and numerical modelling of S960 ultra-high strength steel angle and Channel Section stub columns
Engineering Structures, 2020Co-Authors: Fangying Wang, Ou Zhao, Ben YoungAbstract:Abstract A comprehensive experimental and numerical study of the cross-Sectional compressive behaviour and resistances of press-braked S960 ultra-high strength steel (UHSS) angle and Channel Section stub columns is reported in this paper. The experimental study was carried out on four equal-leg angle Sections and eight plain Channel Sections, and comprised material testing, initial local geometric imperfection measurements and 18 stub column tests. The experimental setups, procedures and key observations were fully presented. The experimental study was then supplemented by a finite element (FE) simulation programme, in which FE models were firstly developed to replicate the test structural responses and subsequently used to generate further numerical data over a wide variety of cross-Section sizes. It is worth noting that the current international standards established in Europe, America and Australia/New Zealand only cover the design of structural members with material grades up to S700, and thus the examined S960 UHSS angle and Channel Section stub columns are out of the scope of the existing design standards. In this study, the experimentally and numerically acquired data was adopted to assess the applicability of the codified provisions and formulations to the design of S960 UHSS angle and Channel Section stub columns. The assessment results generally indicated that the current European code leads to overall consistent and accurate predictions of cross-Section compression resistances, but with many overestimated predicted resistances for S960 UHSS Channel Section stub columns, while the American and Australian/New Zealand standards yield unduly scattered design cross-Section compression resistances, with unsafe and overly conservative predicted resistances respectively for S960 UHSS Channel Section stub columns and slender angle Section stub columns. Revised codified design rules were also proposed, and shown to yield safe, accurate and consistent design cross-Section compression resistances for S960 UHSS angle and Channel Section stub columns.
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Local stability of press-braked stainless steel angle and Channel Sections: Testing, numerical modelling and design analysis
Engineering Structures, 2020Co-Authors: Lulu Zhang, Ou ZhaoAbstract:Abstract This paper reports an experimental and numerical investigation into the local stability of press-braked stainless steel angle and Channel Sections. The experimental programme was performed on two equal-leg angle Sections and two plain Channel Sections, and included material testing, initial local geometric imperfection measurements, eight stub column tests and ten laterally restrained beam tests (about the geometric axes for angle Sections and minor principal axes for Channel Sections). This was supplemented by a numerical simulation programme, where finite element models were firstly established to replicate the test structural responses and then employed to derive further numerical data through parametric studies. The results obtained from the structural testing and numerical modelling were adopted to evaluate the accuracy of the codified local buckling design provisions established in America, Europe and Australia and New Zealand. The evaluation results revealed that all the design codes greatly underestimate the cross-Section resistances of press-braked stainless steel equal-leg angle and plain Channel Section stub columns and laterally restrained beams, mainly attributed to the neglect of the pronounced material strain hardening effect of stainless steel in the design. The continuous strength method (CSM) is an advanced deformation-based design method, allowing for a rational utilisation of material strain hardening in determining cross-Section resistances, and its scope of application has been recently extended from doubly-symmetric (I- and tubular) Sections to mono-symmetric and asymmetric (angle, Channel and T-) Sections. Quantitative evaluation of the CSM was conducted through comparing the predicted cross-Section resistances against the experimental and numerical results. The CSM was found to yield substantially more accurate and consistent design cross-Section resistances for press-braked stainless steel equal-leg angle and plain Channel Section stub columns and laterally restrained beams than the established design codes.
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Press-braked S690 high strength steel equal-leg angle and plain Channel Section stub columns: Testing, numerical simulation and design
Engineering Structures, 2019Co-Authors: Lulu Zhang, Fangying Wang, Yating Liang, Ou ZhaoAbstract:Abstract This paper reports an experimental and numerical investigation into the cross-Section behaviour and compression resistances of press-braked S690 high strength steel angle and Channel Section stub columns. The experimental study was carried out on four equal-leg angle Sections and eight plain Channel Sections with a range of cross-Section sizes (covering both non-slender and slender Sections), and included thirty-six material tensile flat and corner coupon tests, initial local geometric imperfection measurements and twenty-four concentrically loaded stub column tests. The experimental study was then supplemented by a numerical modelling programme, where numerical models were firstly developed to simulate the test structural responses and subsequently adopted to derive further numerical data. The experimentally and numerically derived results were utilised to assess the applicability of the Eurocode Class 3 slenderness limits for hot-rolled and welded Sections to their cold-formed (press-braked) counterparts. The results of the assessment generally revealed that the Eurocode Class 3 slenderness limits for hot-rolled and welded Sections can be safely adopted for the classification of press-braked (cold-formed) S690 high strength steel angle and Channel Sections subjected to compression. The accuracy of the codified design provisions established in Europe, North America and Australia/New Zealand as well as the direct strength method (DSM) to the design of press-braked S690 high strength steel angle and Channel Section stub columns was also assessed, based on the test data and numerical results. The North American, Australian and New Zealand standards were found to result in accurate and consistent compression capacity predictions for press-braked S690 high strength steel Channel Section and non-slender angle Section stub columns, but greatly underestimate the compression capacities for those slender angle Section stub columns, while the European code and DSM were shown to yield overall precise and consistent design compression capacities.
Andrzej Teter - One of the best experts on this subject based on the ideXlab platform.
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local buckling post buckling and collapse of thin walled Channel Section composite columns subjected to quasi static compression
Composite Structures, 2016Co-Authors: Hubert Debski, Tomasz Kubiak, Andrzej Teter, Sylwester SamborskiAbstract:Abstract A post-buckling behaviour analysis and an ultimate load estimation of thin-walled composite Channel columns under a constant rate of end shortening are presented. The columns with C-Sections were made of a carbon-epoxy composite – a laminate consisting of eight symmetrically oriented plies. Four different layer arrangements were taken into consideration. The main objective of the study was to investigate the behaviour of the considered columns under quasi-static compression to achieve their collapse. The experimental tests were performed under standard conditions on a universal ZWICK Z100 testing machine. To collect the experimental data, strain gauges for strain measurements, a laser gauge for deflections and acoustic emission testing equipment were employed. A numerical analysis was conducted with the Abaqus commercial FEM software package. The experimental results were then used to develop FEM models that allowed one to describe the post-buckling behaviour and to estimate the ultimate load-carrying capacity of the composite Channels under investigation.
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experimental investigation of failure process in compressed Channel Section gfrp laminate columns assisted with the acoustic emission method
Composite Structures, 2015Co-Authors: Tomasz Kubiak, Sylwester Samborski, Andrzej TeterAbstract:Abstract The experimental investigations of thin-walled Channel Section columns subjected to static compression are described. The columns under consideration were made of eight layers of a glass/epoxy unidirectional prepreg tape, with the autoclaving technique. Six different symmetrical layer arrangements were taken into account. The tests were performed on a Zwick Z100/SN3A universal testing machine with special self-aligning grips. The columns under investigation were loaded with the force values from zero to the maximal load destroying the profile, which allowed one to observe the column behaviour till its collapse. The strain gauges measurement technique was employed to determine the equilibrium paths, the buckling loads and the post-buckling behaviour. During all the tests, AMSY-5 AE equipment made by the Vallen company was applied to detect acoustic emission phenomena. The acoustic emission method allowed to investigate the behaviour of composite structures in the phase prior to their collapse. The results of the experimental investigations were employed to validate the proposed FE model in order to analyse the post-buckling behaviour and to determine the failure load with the well-known failure criteria.
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experimental investigation of Channel Section composite profiles behavior with various sequences of plies subjected to static compression
Thin-walled Structures, 2013Co-Authors: Hubert Debski, Tomasz Kubiak, Andrzej TeterAbstract:Abstract This paper deals with the buckling of thin-walled Channel-Section composite columns subjected to static compression. It was assumed that the columns were supported with articulated joints at both ends. For experimental testing, three series of specimens were manufactured with autoclaving technique. The specimens had identical dimensions but differed about ply sequence. The Hexcel′s HexPly M12 carbon-epoxy prepreg was used in order to fabricate the Channel-Section profiles. During the stand tests minimal critical forces of the real structure and the corresponding buckling modes were determined with an application of electrical strain gauges. In addition, post-critical equilibrium paths for small overloads—150% of the critical load for the ideal structure—were determined. The experimental results were compared to the ones obtained numerically with the finite element method (FEM).
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buckling and postbuckling behaviour of thin walled composite Channel Section column
Composite Structures, 2013Co-Authors: Hubert Debski, Tomasz Kubiak, Andrzej TeterAbstract:Abstract The article presents results of experimental investigations of thin-walled columns made with carbon fibre composite. Experimental studies were conducted to confirm results obtained from numerical calculations, which was performed using finite element method and proposed analytical–numerical method. The studies consisted of axially compressed thin-walled Channel Section columns.
Tomasz Kubiak - One of the best experts on this subject based on the ideXlab platform.
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local buckling and post buckling of composite Channel Section beams numerical and experimental investigations
Composites Part B-engineering, 2016Co-Authors: Tomasz Kubiak, Zbigniew Kolakowski, Jacek Swiniarski, Mariusz Urbaniak, Adrian GliszczynskiAbstract:Abstract Local buckling and post-buckling of thin-walled composite Channel-Section beams under pure bending are described. Profiles were subject to bending in the plane of the lowest second moment of area. Thin-walled beams were made of an eight-layer GFRP composite with six different arrangements of plies. An asymptotic analytical–numerical method was used in the investigations, whereas the ANSYS software based on the finite element method and the experimental test results were employed in the numerical simulations. The analytical–numerical method is based on asymptotic Koiter's theory for conservative systems, modified by Byskov and Hutchinson. Two different finite element models were prepared: the first one with boundary conditions closer to the analytical–numerical method model and the second one with boundary conditions close to those present on the test stand. A four-point bending test was used in the experimental test. The results obtained in the above-mentioned numerical methods are compared to these obtained experimentally. The advantages and disadvantages of the applied methods and models are presented and discussed.
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local buckling post buckling and collapse of thin walled Channel Section composite columns subjected to quasi static compression
Composite Structures, 2016Co-Authors: Hubert Debski, Tomasz Kubiak, Andrzej Teter, Sylwester SamborskiAbstract:Abstract A post-buckling behaviour analysis and an ultimate load estimation of thin-walled composite Channel columns under a constant rate of end shortening are presented. The columns with C-Sections were made of a carbon-epoxy composite – a laminate consisting of eight symmetrically oriented plies. Four different layer arrangements were taken into consideration. The main objective of the study was to investigate the behaviour of the considered columns under quasi-static compression to achieve their collapse. The experimental tests were performed under standard conditions on a universal ZWICK Z100 testing machine. To collect the experimental data, strain gauges for strain measurements, a laser gauge for deflections and acoustic emission testing equipment were employed. A numerical analysis was conducted with the Abaqus commercial FEM software package. The experimental results were then used to develop FEM models that allowed one to describe the post-buckling behaviour and to estimate the ultimate load-carrying capacity of the composite Channels under investigation.
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experimental investigation of failure process in compressed Channel Section gfrp laminate columns assisted with the acoustic emission method
Composite Structures, 2015Co-Authors: Tomasz Kubiak, Sylwester Samborski, Andrzej TeterAbstract:Abstract The experimental investigations of thin-walled Channel Section columns subjected to static compression are described. The columns under consideration were made of eight layers of a glass/epoxy unidirectional prepreg tape, with the autoclaving technique. Six different symmetrical layer arrangements were taken into account. The tests were performed on a Zwick Z100/SN3A universal testing machine with special self-aligning grips. The columns under investigation were loaded with the force values from zero to the maximal load destroying the profile, which allowed one to observe the column behaviour till its collapse. The strain gauges measurement technique was employed to determine the equilibrium paths, the buckling loads and the post-buckling behaviour. During all the tests, AMSY-5 AE equipment made by the Vallen company was applied to detect acoustic emission phenomena. The acoustic emission method allowed to investigate the behaviour of composite structures in the phase prior to their collapse. The results of the experimental investigations were employed to validate the proposed FE model in order to analyse the post-buckling behaviour and to determine the failure load with the well-known failure criteria.
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selected problems concerning determination of the buckling load of Channel Section beams and columns
Thin-walled Structures, 2015Co-Authors: Maria Paszkiewicz, Tomasz KubiakAbstract:Abstract The issue of buckling load determination in composite Channel Section beams subjected to pure bending and Channel Section columns subjected to uniform compression is considered. Some selected problems with determination of buckling load on the basis of the collected and processed experimental data are discussed. The data necessary to determine buckling load (applied load and the corresponding displacement, strains at chosen points of beam-columns and displacements in three perpendicular directions of all visible points of the considered beam-columns) were collected with a strain gauge system, an Aramis® 3D optical system and a universal testing machine. Buckling load was determined by means of the following well-known methods: the mean strain method, the method of straight-lines interSection on the graph of load vs. mean strains, the curve inflection point method, the load-square of deflection curve method and Koiter’s method. All results were obtained during the experimental investigations and the numerical FEM analysis of the Channel Section profile made of a GFRP laminate with the symmetrical eight-layer arrangement [45/-45/90/0]s. The profiles under consideration were subjected to compression or pure bending (four-point bending test). The rules for each methods of buckling load determination are proposed on the basis of the obtained results.
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influence of autoclaving process parameters on the buckling and postbuckling behaviour of thin walled Channel Section beams
Thin-walled Structures, 2014Co-Authors: Jaroslaw Bienias, Tomasz Kubiak, Adrian Gliszczynski, Patryk Jakubczak, Krzysztof MajerskiAbstract:Abstract The postbuckling behaviour and load carrying capacity of thin-walled composite Channel Sections subjected to uniform compression are presented. An analysis of the influence of parameters of the composite manufacturing process on strength properties and load carrying capacity of the thin-walled structure made of this composite has been conducted. The microstructure characteristics of composites is presented and discussed. The postbuckling behaviour and load carrying capacity of thin-walled Channel Section columns subjected to compression have been determined with the finite element method. The ANSYS software has been employed.
Hubert Debski - One of the best experts on this subject based on the ideXlab platform.
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local buckling post buckling and collapse of thin walled Channel Section composite columns subjected to quasi static compression
Composite Structures, 2016Co-Authors: Hubert Debski, Tomasz Kubiak, Andrzej Teter, Sylwester SamborskiAbstract:Abstract A post-buckling behaviour analysis and an ultimate load estimation of thin-walled composite Channel columns under a constant rate of end shortening are presented. The columns with C-Sections were made of a carbon-epoxy composite – a laminate consisting of eight symmetrically oriented plies. Four different layer arrangements were taken into consideration. The main objective of the study was to investigate the behaviour of the considered columns under quasi-static compression to achieve their collapse. The experimental tests were performed under standard conditions on a universal ZWICK Z100 testing machine. To collect the experimental data, strain gauges for strain measurements, a laser gauge for deflections and acoustic emission testing equipment were employed. A numerical analysis was conducted with the Abaqus commercial FEM software package. The experimental results were then used to develop FEM models that allowed one to describe the post-buckling behaviour and to estimate the ultimate load-carrying capacity of the composite Channels under investigation.
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failure analysis of thin walled composite Channel Section columns
Composite Structures, 2015Co-Authors: Hubert Debski, Jozef JonakAbstract:Abstract The paper presents the numerical and experimental results of investigations into nonlinear stability and limit states of axially-compressed thin-walled composite columns with Channel Section. The primary aim of the research was to examine the process of composite failure using the finite element method. The phenomenon of composite failure was described by the Tsai–Wu failure criterion using the commercial software suite ABAQUS®. The numerical results were then compared with the results of experiments wherein physical models of Channel Section structures were subjected to a full range of load conditions until their failure. This approach provided instant validation of designed FEM numerical models for describing limit states of the tested structures.
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experimental investigation of Channel Section composite profiles behavior with various sequences of plies subjected to static compression
Thin-walled Structures, 2013Co-Authors: Hubert Debski, Tomasz Kubiak, Andrzej TeterAbstract:Abstract This paper deals with the buckling of thin-walled Channel-Section composite columns subjected to static compression. It was assumed that the columns were supported with articulated joints at both ends. For experimental testing, three series of specimens were manufactured with autoclaving technique. The specimens had identical dimensions but differed about ply sequence. The Hexcel′s HexPly M12 carbon-epoxy prepreg was used in order to fabricate the Channel-Section profiles. During the stand tests minimal critical forces of the real structure and the corresponding buckling modes were determined with an application of electrical strain gauges. In addition, post-critical equilibrium paths for small overloads—150% of the critical load for the ideal structure—were determined. The experimental results were compared to the ones obtained numerically with the finite element method (FEM).
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buckling and postbuckling behaviour of thin walled composite Channel Section column
Composite Structures, 2013Co-Authors: Hubert Debski, Tomasz Kubiak, Andrzej TeterAbstract:Abstract The article presents results of experimental investigations of thin-walled columns made with carbon fibre composite. Experimental studies were conducted to confirm results obtained from numerical calculations, which was performed using finite element method and proposed analytical–numerical method. The studies consisted of axially compressed thin-walled Channel Section columns.
Fangying Wang - One of the best experts on this subject based on the ideXlab platform.
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Experimental and numerical studies of pin-ended press-braked S960 ultra-high strength steel Channel Section columns
Engineering Structures, 2020Co-Authors: Fangying Wang, Yating Liang, Ou ZhaoAbstract:Abstract Grade S960 ultra-high strength steel is receiving increasing attention owing to its excellent strength-to-weight ratio. However, its application in construction engineering is rather limited due to the lack of adequate design rules, as the current established codes in Europe, North America and Australia/New Zealand only cover the design of steel components with material grades up to S700 (or S690). This prompts investigations into different types of S960 UHSS structural components and development of accurate and efficient design rules for them. The present paper focuses on press-braked S960 UHSS Channel Section columns prone to flexural buckling about the minor principal axes, with their behaviour and resistances thoroughly examined through experiments and numerical modelling. An experimental programme was firstly performed on two non-slender press-braked Channel Sections, with five column specimens of varying member lengths employed for each cross-Section, and included initial global and local geometric imperfection measurements and pin-ended column tests about the minor principal axes. This was followed by a parallel numerical modelling programme, where finite element (FE) models were developed to simulate the experimental results and afterwards adopted to perform a parametric study to generate additional numerical data over a broader spectrum of cross-Section dimensions and member lengths. It is worth noting that there were two orientations associated with minor-axis flexural buckling of press-braked S960 UHSS Channel Section columns, namely ‘C’ orientation (indicating that columns buckled towards the webs) and ‘reverse C’ orientation (indicating that columns buckled towards the flange tips), and both of the two types of failure modes were carefully examined in the present study. It was found that Channel Section columns failing by flexural buckling in the ‘reverse C’ orientation generally exhibited superior resistances relative to their counterparts with failure in the ‘C’ orientation. The experimental and numerical data were also used to assess the applicability of the codified provisions for press-braked S700 (or S690) Channel Section columns failing by flexural buckling about the minor principal axes to the design of their S960 counterparts. The assessment results indicated that (i) the existing European code leads to overall conservative and scattered design flexural buckling resistances, especially for those relatively short and intermediate press-braked S960 UHSS Channel Section columns with failure in the ‘reverse C’ orientation, and (ii) the North American specification and Australian/New Zealand standard result in a higher degree of design accuracy and consistency than the European code, but with many over-predicted flexural buckling resistances for press-braked S960 UHSS Channel Section short and intermediate columns failing in the ‘C’ orientation.
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Experimental and numerical studies of press-braked S690 high strength steel Channel Section beams
Thin-walled Structures, 2020Co-Authors: Lulu Zhang, Fangying Wang, Yating Liang, Ou ZhaoAbstract:Abstract The present paper describes an in-depth experimental and numerical investigation into the flexural responses and strengths of press-braked S690 high strength steel Channel Section beams bent about the minor principal axes in both the ‘u’ and ‘n’ orientations. The experimental study was performed on eight press-braked Channel Sections, and comprised twenty-four material flat and corner coupon tests, initial local geometric imperfection measurements, and twelve beam tests in the four-point bending configuration. This was followed by a complementary numerical modelling programme, where finite element models were firstly developed and validated against the test results and afterwards adopted for performing parametric studies to obtain an additional numerical data bank over a wide variety of cross-Section geometric sizes. The acquired test and numerical data were then employed to evaluate the applicability of the Eurocode slenderness limits for welded and hot-rolled internal webs (in compression) and outstand flanges (in stress gradients) to their press-braked counterparts, revealing that the Eurocode slenderness limits can be safely extended to cover the classifications of plate elements and cross-Sections of press-braked S690 high strength steel Channel Section beams. Evaluation of the accuracy of the cross-Section flexural strengths predicted from various design codes established in Europe, North America and Australia/New Zealand was also made, based on the test and numerical data. The results of the quantitative evaluation generally revealed that (i) all the examined design codes lead to overall conservative and scattered predicted cross-Section flexural strengths for press-braked S690 high strength steel Channel Section beams, and (ii) the European code results in more precise design flexural strengths for beams with relatively stocky Channel Sections, but less accurate strength predictions for beams with relatively slender Channel Sections, compared to the North American and Australian/New Zealand standards.
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Testing and numerical modelling of S960 ultra-high strength steel angle and Channel Section stub columns
Engineering Structures, 2020Co-Authors: Fangying Wang, Ou Zhao, Ben YoungAbstract:Abstract A comprehensive experimental and numerical study of the cross-Sectional compressive behaviour and resistances of press-braked S960 ultra-high strength steel (UHSS) angle and Channel Section stub columns is reported in this paper. The experimental study was carried out on four equal-leg angle Sections and eight plain Channel Sections, and comprised material testing, initial local geometric imperfection measurements and 18 stub column tests. The experimental setups, procedures and key observations were fully presented. The experimental study was then supplemented by a finite element (FE) simulation programme, in which FE models were firstly developed to replicate the test structural responses and subsequently used to generate further numerical data over a wide variety of cross-Section sizes. It is worth noting that the current international standards established in Europe, America and Australia/New Zealand only cover the design of structural members with material grades up to S700, and thus the examined S960 UHSS angle and Channel Section stub columns are out of the scope of the existing design standards. In this study, the experimentally and numerically acquired data was adopted to assess the applicability of the codified provisions and formulations to the design of S960 UHSS angle and Channel Section stub columns. The assessment results generally indicated that the current European code leads to overall consistent and accurate predictions of cross-Section compression resistances, but with many overestimated predicted resistances for S960 UHSS Channel Section stub columns, while the American and Australian/New Zealand standards yield unduly scattered design cross-Section compression resistances, with unsafe and overly conservative predicted resistances respectively for S960 UHSS Channel Section stub columns and slender angle Section stub columns. Revised codified design rules were also proposed, and shown to yield safe, accurate and consistent design cross-Section compression resistances for S960 UHSS angle and Channel Section stub columns.
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Press-braked S690 high strength steel equal-leg angle and plain Channel Section stub columns: Testing, numerical simulation and design
Engineering Structures, 2019Co-Authors: Lulu Zhang, Fangying Wang, Yating Liang, Ou ZhaoAbstract:Abstract This paper reports an experimental and numerical investigation into the cross-Section behaviour and compression resistances of press-braked S690 high strength steel angle and Channel Section stub columns. The experimental study was carried out on four equal-leg angle Sections and eight plain Channel Sections with a range of cross-Section sizes (covering both non-slender and slender Sections), and included thirty-six material tensile flat and corner coupon tests, initial local geometric imperfection measurements and twenty-four concentrically loaded stub column tests. The experimental study was then supplemented by a numerical modelling programme, where numerical models were firstly developed to simulate the test structural responses and subsequently adopted to derive further numerical data. The experimentally and numerically derived results were utilised to assess the applicability of the Eurocode Class 3 slenderness limits for hot-rolled and welded Sections to their cold-formed (press-braked) counterparts. The results of the assessment generally revealed that the Eurocode Class 3 slenderness limits for hot-rolled and welded Sections can be safely adopted for the classification of press-braked (cold-formed) S690 high strength steel angle and Channel Sections subjected to compression. The accuracy of the codified design provisions established in Europe, North America and Australia/New Zealand as well as the direct strength method (DSM) to the design of press-braked S690 high strength steel angle and Channel Section stub columns was also assessed, based on the test data and numerical results. The North American, Australian and New Zealand standards were found to result in accurate and consistent compression capacity predictions for press-braked S690 high strength steel Channel Section and non-slender angle Section stub columns, but greatly underestimate the compression capacities for those slender angle Section stub columns, while the European code and DSM were shown to yield overall precise and consistent design compression capacities.
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Flexural behaviour and strengths of press-braked S960 ultra-high strength steel Channel Section beams
Engineering Structures, 2019Co-Authors: Fangying Wang, Ou Zhao, Ben YoungAbstract:Abstract A thorough experimental and numerical study of the flexural behaviour and strengths of press-braked S960 ultra-high strength steel (UHSS) Channel Section beams bent about the minor principal axes is reported in this paper. The experimental study was conducted on eight different UHSS plain Channel Sections, and included measurements on the material flat and corner properties and initial local geometric imperfections of the beam specimens as well as 20 four-point bending tests performed about the minor principal axes in both the ‘u’ and ‘n’ orientations. A complementary numerical investigation was then conducted, where finite element (FE) models were firstly developed and validated against the experimental results, followed by parametric studies carried out to acquire further numerical data over a broader range of cross-Section dimensions. It is worth noting that the existing design codes for steel structures, as established in Europe, America and Australia/New Zealand, are only applicable to those with material grades up to S690 (or S700 for Eurocode) and cannot be directly used for S960 UHSS structural members. In the present study, the applicability of the codified design provisions and formulations for flexural members to the examined S960 UHSS Channel Section beams was evaluated, based on the ultimate moments derived from structural testing and numerical modelling. The quantitative evaluation results generally revealed that the current European code provides overall consistent and precise flexural strength predictions for Class 1 and Class 2 S960 UHSS Channel Sections in minor-axis bending, but leads to a high level of inaccuracy (scatter and conservatism) for the design of their Class 3 and Class 4 counterparts, whilst the American specification and Australian/New Zealand standard result in scattered and excessively underestimated design flexural strengths, except for the cases of slender S960 UHSS Channel Section beams in ‘u’-orientation bending.