Pub Date : 2021-01-01DOI: 10.12989/SCS.2021.39.1.001
M. S. Beg, Hasan M. Khalid, M. Y. Yasin, L. Hadji
An exact solution based on refined third-order theory (TOT) has been presented for functionally graded porous curved beams having deep curvature. The displacement field of the refined TOT is derived by imposing the shear free conditions at the outer and inner surfaces of curved beams. The properties of the two phase composite are tailored according the power law rule and the effective properties are computed using Mori-Tanaka homogenization scheme. The equations of motion as well as consistent boundary conditions are derived using the Hamilton's principle. The curved beam stiffness coefficients (A, B, D) are obtained numerically using six-point Gauss integration scheme without compromising the accuracy due to deepness (1+z/R) terms. The porosity has been modeled assuming symmetric (even) as well as asymmetric (uneven) distributions across the cross section of curved beam. The programming has been performed in MATLAB and is validated with the results available in the literature as well as 2D finite element model developed in ABAQUS. The effect of inclusion of 1+z/R terms is studied for deflection, stresses and natural frequencies for FG curved beams of different radii of curvature. Results presented in this work will be useful for comparison of future studies.
{"title":"Exact third-order static and free vibration analyses of functionally graded porous curved beam","authors":"M. S. Beg, Hasan M. Khalid, M. Y. Yasin, L. Hadji","doi":"10.12989/SCS.2021.39.1.001","DOIUrl":"https://doi.org/10.12989/SCS.2021.39.1.001","url":null,"abstract":"An exact solution based on refined third-order theory (TOT) has been presented for functionally graded porous curved beams having deep curvature. The displacement field of the refined TOT is derived by imposing the shear free conditions at the outer and inner surfaces of curved beams. The properties of the two phase composite are tailored according the power law rule and the effective properties are computed using Mori-Tanaka homogenization scheme. The equations of motion as well as consistent boundary conditions are derived using the Hamilton's principle. The curved beam stiffness coefficients (A, B, D) are obtained numerically using six-point Gauss integration scheme without compromising the accuracy due to deepness (1+z/R) terms. The porosity has been modeled assuming symmetric (even) as well as asymmetric (uneven) distributions across the cross section of curved beam. The programming has been performed in MATLAB and is validated with the results available in the literature as well as 2D finite element model developed in ABAQUS. The effect of inclusion of 1+z/R terms is studied for deflection, stresses and natural frequencies for FG curved beams of different radii of curvature. Results presented in this work will be useful for comparison of future studies.","PeriodicalId":51177,"journal":{"name":"Steel and Composite Structures","volume":"39 1","pages":"1"},"PeriodicalIF":4.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66590683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SCS.2021.39.2.215
Abdeljalil Meksi, S. Benyoucef, M. Sekkal, R. B. Bouiadjra, M. Selim, A. Tounsi, M. Hussain
This paper investigates the effect of micromechanical models on the bending behavior of bidirectional functionally graded (BDFG) beams subjected to different mechanical loading. The material properties of the beam are considered to be graded in both axial and thickness directions according to a power law. The beam's behavior is modeled by the mean of quasi 3D displacement field that contain undetermined integral terms and involves a reduced unknown functions. Navier's method is employed to determine and compute the displacements and stress for a simply supported beam. Different homogenization schemes such as Voigt, Reus, and Mori-Tanaka are employed to analyze the response of the BDFG beam subjected to linear, uniform, exponential and sinusoidal distributed loading. The results obtained by the present method are compared with available results in the literature and a good agreement was found. Several numerical results are presented in tabular form and in figures to examine the effects of the material gradation, micromechanical models and types of loading on the bending response of BDFG beams. It can be concluded that the present theory is not only accurate but also simple in predicting the bending response of BDFG beam subjected to different static loads.
{"title":"Influence of micromechanical models on the bending response of bidirectional FG beams under linear, uniform, exponential and sinusoidal distributed loading","authors":"Abdeljalil Meksi, S. Benyoucef, M. Sekkal, R. B. Bouiadjra, M. Selim, A. Tounsi, M. Hussain","doi":"10.12989/SCS.2021.39.2.215","DOIUrl":"https://doi.org/10.12989/SCS.2021.39.2.215","url":null,"abstract":"This paper investigates the effect of micromechanical models on the bending behavior of bidirectional functionally graded (BDFG) beams subjected to different mechanical loading. The material properties of the beam are considered to be graded in both axial and thickness directions according to a power law. The beam's behavior is modeled by the mean of quasi 3D displacement field that contain undetermined integral terms and involves a reduced unknown functions. Navier's method is employed to determine and compute the displacements and stress for a simply supported beam. Different homogenization schemes such as Voigt, Reus, and Mori-Tanaka are employed to analyze the response of the BDFG beam subjected to linear, uniform, exponential and sinusoidal distributed loading. The results obtained by the present method are compared with available results in the literature and a good agreement was found. Several numerical results are presented in tabular form and in figures to examine the effects of the material gradation, micromechanical models and types of loading on the bending response of BDFG beams. It can be concluded that the present theory is not only accurate but also simple in predicting the bending response of BDFG beam subjected to different static loads.","PeriodicalId":51177,"journal":{"name":"Steel and Composite Structures","volume":"39 1","pages":"215-228"},"PeriodicalIF":4.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66591532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SCS.2021.40.1.075
Y. Tao, Jin-Ben Gu, Jian fei Chen, P. Feng
A fiber-reinforced polymer (FRP)-confined concrete core that provides high strength and ductility under axial compression can act as strength enhancement in a hybrid column. In the present study, ordinary concrete was replaced with ultra-high-performance concrete (UHPC) to form an FRP-confined UHPC core (FCUC). The FCUC was embedded in square concrete-filled steel tube (CFST) columns to form a high-performance hybrid column (SCF-UHPC column for short). The axial compressive behavior of the SCF-UHPC was experimentally investigated using 12 SCF-UHPC columns and two ordinary CFST columns for comparison. The advantages of the SCF-UHPC include excellent axial load-bearing capacity, good ductility, and stable residual load-bearing capacity. The results show that failure of an SCF-UHPC column was caused by FRP rupture of FCUC, which occurred after steel tube buckling that results in the degraded stiffness. It was also shown that the load-displacement behavior of the SCF-UHPC composite column was determined by the UHPC core diameter and the corresponding confinement provided by the outer steel tube and inner FRP jacket. A hardening effect could be achieved when the confinement demand of the UHPC core was satisfied, whereas a plateau effect appeared if the confinement was insufficient. Furthermore, the load-bearing capacity and ductility of the SCF-UHPC columns improved with increased thickness of the steel tube and the FRP.
{"title":"Behavior of hybrid CFST with FRP-confined UHPC core under axial compression","authors":"Y. Tao, Jin-Ben Gu, Jian fei Chen, P. Feng","doi":"10.12989/SCS.2021.40.1.075","DOIUrl":"https://doi.org/10.12989/SCS.2021.40.1.075","url":null,"abstract":"A fiber-reinforced polymer (FRP)-confined concrete core that provides high strength and ductility under axial compression can act as strength enhancement in a hybrid column. In the present study, ordinary concrete was replaced with ultra-high-performance concrete (UHPC) to form an FRP-confined UHPC core (FCUC). The FCUC was embedded in square concrete-filled steel tube (CFST) columns to form a high-performance hybrid column (SCF-UHPC column for short). The axial compressive behavior of the SCF-UHPC was experimentally investigated using 12 SCF-UHPC columns and two ordinary CFST columns for comparison. The advantages of the SCF-UHPC include excellent axial load-bearing capacity, good ductility, and stable residual load-bearing capacity. The results show that failure of an SCF-UHPC column was caused by FRP rupture of FCUC, which occurred after steel tube buckling that results in the degraded stiffness. It was also shown that the load-displacement behavior of the SCF-UHPC composite column was determined by the UHPC core diameter and the corresponding confinement provided by the outer steel tube and inner FRP jacket. A hardening effect could be achieved when the confinement demand of the UHPC core was satisfied, whereas a plateau effect appeared if the confinement was insufficient. Furthermore, the load-bearing capacity and ductility of the SCF-UHPC columns improved with increased thickness of the steel tube and the FRP.","PeriodicalId":51177,"journal":{"name":"Steel and Composite Structures","volume":"33 1","pages":"75-85"},"PeriodicalIF":4.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66594185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SCS.2021.40.1.101
M. Najafi, I. Ahmadi
In this study, a nonlocal Layerwise theory is presented for free vibration analysis of nanobeams resting on an elastic foundation. Eringen's nonlocal elasticity theory is used to consider the small-scale effect on behavior of nanobeam. The governing equations are obtained by employing Hamilton's principle and Layerwise theory of beams and Eringen's nonlocal constitutive equation. The presented theory takes into account the in-plane and transverse normal and shear strain in the modeling of the nanobeam and can predict more accurate results. The governing equations of the beam are solved by Navier's method for Simple-Simple boundary conditions and semi-analytical methods to obtain the natural frequency for various boundary conditions including Clamped-Simple (C-S), Clamped-Clamped (C-C) and Free-Free (F-F) boundary conditions. Predictions of the present theory are compared with benchmark results in the literature. Effects of nonlocal parameter, Pasternak shear coefficient, Winkler spring coefficient, boundary conditions, and the aspect ratio on the free vibration of nanobeams are studied. The flexural mode and thickness mode natural frequencies of the nanobeam are predicted. It is shown that the predictions of present method are more accurate than the equivalent single layer theories. The theoretical developments and formulation presented herein should also be served to analyze the mechanical behavior of various nanostructures with various loading and boundary conditions.
{"title":"A nonlocal Layerwise theory for free vibration analysis of nanobeams with various boundary conditions on Winkler-Pasternak foundation","authors":"M. Najafi, I. Ahmadi","doi":"10.12989/SCS.2021.40.1.101","DOIUrl":"https://doi.org/10.12989/SCS.2021.40.1.101","url":null,"abstract":"In this study, a nonlocal Layerwise theory is presented for free vibration analysis of nanobeams resting on an elastic foundation. Eringen's nonlocal elasticity theory is used to consider the small-scale effect on behavior of nanobeam. The governing equations are obtained by employing Hamilton's principle and Layerwise theory of beams and Eringen's nonlocal constitutive equation. The presented theory takes into account the in-plane and transverse normal and shear strain in the modeling of the nanobeam and can predict more accurate results. The governing equations of the beam are solved by Navier's method for Simple-Simple boundary conditions and semi-analytical methods to obtain the natural frequency for various boundary conditions including Clamped-Simple (C-S), Clamped-Clamped (C-C) and Free-Free (F-F) boundary conditions. Predictions of the present theory are compared with benchmark results in the literature. Effects of nonlocal parameter, Pasternak shear coefficient, Winkler spring coefficient, boundary conditions, and the aspect ratio on the free vibration of nanobeams are studied. The flexural mode and thickness mode natural frequencies of the nanobeam are predicted. It is shown that the predictions of present method are more accurate than the equivalent single layer theories. The theoretical developments and formulation presented herein should also be served to analyze the mechanical behavior of various nanostructures with various loading and boundary conditions.","PeriodicalId":51177,"journal":{"name":"Steel and Composite Structures","volume":"40 1","pages":"101"},"PeriodicalIF":4.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66594339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SCS.2021.40.1.033
Peng Wang, Q. Shi, F. Wang, Q. Wang
Based on finite element software, a simulation programme is used to evaluate the seismic behaviour of new-type steel-reinforced concrete (SRC) columns, called enlarged cross steel-reinforced concrete (ECSRC) columns. With abundant simulations, the effects of the loading paths, number of loading cycles, incremental amplitude of displacement and variable axial load on the seismic response of the ECSRC columns were investigated. The results indicate that the seismic behaviour of the column is highly dependent on the loading paths, and it was observed that the loading paths produced a significant effect on the hysteretic response of the columns. Compared with those under uniaxial loading, the yield load, maximum load, ultimate displacement and ductility coefficient of the ECSRC columns under biaxial loading are reduced by 13.47%, 18.01%, 12.17% and 32.64%, respectively. The energy dissipation capacity of the columns is highly dependent on the loading paths. The skeleton curves are not significantly influenced by the number of loading cycles until the yield point of steel and longitudinal reinforcement is reached. With an increase in loading cycles, the yield load, yield displacement, ductility coefficient and maximum load, as well as the corresponding horizontal displacement of the column, are reduced, while the energy dissipation grows. In addition, the yield displacement, yield load, and ductility coefficient increase with an increase in the incremental amplitude of displacement; however, the energy dissipation decreases under these conditions. The seismic performance of the SRC column under variable axial loads clearly exhibits asymmetry that is worse than that observed under constant axial loads.
{"title":"Seismic behaviour of enlarged cross steel-reinforced concrete columns under various loadings","authors":"Peng Wang, Q. Shi, F. Wang, Q. Wang","doi":"10.12989/SCS.2021.40.1.033","DOIUrl":"https://doi.org/10.12989/SCS.2021.40.1.033","url":null,"abstract":"Based on finite element software, a simulation programme is used to evaluate the seismic behaviour of new-type steel-reinforced concrete (SRC) columns, called enlarged cross steel-reinforced concrete (ECSRC) columns. With abundant simulations, the effects of the loading paths, number of loading cycles, incremental amplitude of displacement and variable axial load on the seismic response of the ECSRC columns were investigated. The results indicate that the seismic behaviour of the column is highly dependent on the loading paths, and it was observed that the loading paths produced a significant effect on the hysteretic response of the columns. Compared with those under uniaxial loading, the yield load, maximum load, ultimate displacement and ductility coefficient of the ECSRC columns under biaxial loading are reduced by 13.47%, 18.01%, 12.17% and 32.64%, respectively. The energy dissipation capacity of the columns is highly dependent on the loading paths. The skeleton curves are not significantly influenced by the number of loading cycles until the yield point of steel and longitudinal reinforcement is reached. With an increase in loading cycles, the yield load, yield displacement, ductility coefficient and maximum load, as well as the corresponding horizontal displacement of the column, are reduced, while the energy dissipation grows. In addition, the yield displacement, yield load, and ductility coefficient increase with an increase in the incremental amplitude of displacement; however, the energy dissipation decreases under these conditions. The seismic performance of the SRC column under variable axial loads clearly exhibits asymmetry that is worse than that observed under constant axial loads.","PeriodicalId":51177,"journal":{"name":"Steel and Composite Structures","volume":"40 1","pages":"33-43"},"PeriodicalIF":4.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66594368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SCS.2021.40.2.175
Li-Hua Zhu, Gang Li, Zhiqian Dong
The structural damage or collapse caused by weak-story failure mechanisms poses a great threat to the safety of human life and property under strong earthquakes. Many researchers have attempted to transform this unexpected failure mechanism into the desired overall failure mechanism by installing various energy dissipation devices on unsafe structures. This paper introduced a lattice-shaped friction device (LSFD), which is a friction device with hardening postyielding stiffness, into a steel frame with a weak-story failure mechanism. Then, shaking table tests of a three types of two-story steel frames—a frame with LSFDs, a frame with traditional friction brace dampers (FBDs), and a bare frame—were carried out. The seismic responses of the hardening postyielding stiffness of the LSFD on the weak-story failure mechanism of the frame were emphatically studied. The results showed that there was little difference in the seismic responses between the two damped structures under moderate and weak earthquakes. The distribution of maximum story drift for the structure with LSFDs was more uniform, which effectively suppressed the weak-story failure under strong earthquakes, whereas the structure with FBDs had serious deformation concentrations. The numerical simulation results of the structure with LSFDs in the shaking table test showed that the simplified model results were basically consistent with the experimental results. Hence, this model could be used to analyze the seismic performance of damped structures with LSFDs.
{"title":"Dynamic test and numerical simulation on avoiding the weak-story failure mechanism in structures using LSFDs","authors":"Li-Hua Zhu, Gang Li, Zhiqian Dong","doi":"10.12989/SCS.2021.40.2.175","DOIUrl":"https://doi.org/10.12989/SCS.2021.40.2.175","url":null,"abstract":"The structural damage or collapse caused by weak-story failure mechanisms poses a great threat to the safety of human life and property under strong earthquakes. Many researchers have attempted to transform this unexpected failure mechanism into the desired overall failure mechanism by installing various energy dissipation devices on unsafe structures. This paper introduced a lattice-shaped friction device (LSFD), which is a friction device with hardening postyielding stiffness, into a steel frame with a weak-story failure mechanism. Then, shaking table tests of a three types of two-story steel frames—a frame with LSFDs, a frame with traditional friction brace dampers (FBDs), and a bare frame—were carried out. The seismic responses of the hardening postyielding stiffness of the LSFD on the weak-story failure mechanism of the frame were emphatically studied. The results showed that there was little difference in the seismic responses between the two damped structures under moderate and weak earthquakes. The distribution of maximum story drift for the structure with LSFDs was more uniform, which effectively suppressed the weak-story failure under strong earthquakes, whereas the structure with FBDs had serious deformation concentrations. The numerical simulation results of the structure with LSFDs in the shaking table test showed that the simplified model results were basically consistent with the experimental results. Hence, this model could be used to analyze the seismic performance of damped structures with LSFDs.","PeriodicalId":51177,"journal":{"name":"Steel and Composite Structures","volume":"40 1","pages":"175"},"PeriodicalIF":4.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66594521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SCS.2021.40.1.139
Wenhua Huang, V. Tahouneh
The goal of this study is to fill this apparent gap in the area about investigating free vibration of Functionally Graded Piezoelectric Materials (FGPMs) nanobeams with porosity resting on two-parameter elastic foundations, under voltage load considering Timoshenko beam model and nonlocal theory. The elastic foundation is considered as a Pasternak model with adding a shear layer to the Winkler model. The electromechanical and mechanical properties of the nanobeam (such as elastic, piezoelectric, dielectric coefficients and mass density) are FG in the thickness direction of the beam. Based on Hamilton principle, governing equations of the problem are derived. The Differential Quadrature Method (DQM) for solution of these equations are employed to determine the natural frequencies of the FGPM nanobeams at different Boundary Conditions (B.C.s). The influences of supporting conditions, the porosity coefficient and patterns including even and uneven, nonlocal parameter, Winkler foundation modulus, shear elastic foundation modulus, external voltage and power-law index on the electromechanical vibration characteristics of the FGPM nanobeams are discussed in details. It is found that the FG index and nonlocal parameter will reduce the natural frequencies of the FG nanobeam, while the Winkler and Pasternak moduli of the foundation show an opposite tendency.
{"title":"Frequency study of porous FGPM beam on two-parameter elastic foundations via Timoshenko theory","authors":"Wenhua Huang, V. Tahouneh","doi":"10.12989/SCS.2021.40.1.139","DOIUrl":"https://doi.org/10.12989/SCS.2021.40.1.139","url":null,"abstract":"The goal of this study is to fill this apparent gap in the area about investigating free vibration of Functionally Graded Piezoelectric Materials (FGPMs) nanobeams with porosity resting on two-parameter elastic foundations, under voltage load considering Timoshenko beam model and nonlocal theory. The elastic foundation is considered as a Pasternak model with adding a shear layer to the Winkler model. The electromechanical and mechanical properties of the nanobeam (such as elastic, piezoelectric, dielectric coefficients and mass density) are FG in the thickness direction of the beam. Based on Hamilton principle, governing equations of the problem are derived. The Differential Quadrature Method (DQM) for solution of these equations are employed to determine the natural frequencies of the FGPM nanobeams at different Boundary Conditions (B.C.s). The influences of supporting conditions, the porosity coefficient and patterns including even and uneven, nonlocal parameter, Winkler foundation modulus, shear elastic foundation modulus, external voltage and power-law index on the electromechanical vibration characteristics of the FGPM nanobeams are discussed in details. It is found that the FG index and nonlocal parameter will reduce the natural frequencies of the FG nanobeam, while the Winkler and Pasternak moduli of the foundation show an opposite tendency.","PeriodicalId":51177,"journal":{"name":"Steel and Composite Structures","volume":"40 1","pages":"139"},"PeriodicalIF":4.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66594833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SCS.2021.40.2.287
Yao Chi, Krishanu Roy, Boshan Chen, Zhiyuan Fang, Asraf Uzzaman, G. Ananthi, James B. P. Lim
Recently, a new generation of cold-formed steel (CFS) channel section with edge-stiffened web holes has been developed by industry in New Zealand. However, no research has been reported in the literature to investigate the axial capacity of back-to-back channels with edge-stiffened web holes. This paper presents a total of 73 new results comprising 29 compression tests and 44 finite element analyses (FEA) on axial capacity of such back-to-back CFS channels. The results show that for back-to-back channels with seven edge-stiffened holes, the axial capacity increased by 19.2%, compared to plain channels without web holes. A non-linear finite element (FE) model was developed and validated against the test results. The validated FE model was used to conduct a parametric study involving 44 FE models. Finely, the tests results were compared with the design strengths calculated from the AISI and AS/NZ standards and from the proposed design equations of Moen and Schafer. From the comparison results, it was found that the AISI and AS/NZ design strengths are only 9% conservative to the test results for plain channels without web holes. While Moen and Schafer equations are conservative by 13% and 47% for axial capacity of CFS back-to-back channels with un-stiffened and edge-stiffened web holes, respectively.
{"title":"Effect of web hole spacing on axial capacity of back-to-back cold-formed steel channels with edge-stiffened holes","authors":"Yao Chi, Krishanu Roy, Boshan Chen, Zhiyuan Fang, Asraf Uzzaman, G. Ananthi, James B. P. Lim","doi":"10.12989/SCS.2021.40.2.287","DOIUrl":"https://doi.org/10.12989/SCS.2021.40.2.287","url":null,"abstract":"Recently, a new generation of cold-formed steel (CFS) channel section with edge-stiffened web holes has been developed by industry in New Zealand. However, no research has been reported in the literature to investigate the axial capacity of back-to-back channels with edge-stiffened web holes. This paper presents a total of 73 new results comprising 29 compression tests and 44 finite element analyses (FEA) on axial capacity of such back-to-back CFS channels. The results show that for back-to-back channels with seven edge-stiffened holes, the axial capacity increased by 19.2%, compared to plain channels without web holes. A non-linear finite element (FE) model was developed and validated against the test results. The validated FE model was used to conduct a parametric study involving 44 FE models. Finely, the tests results were compared with the design strengths calculated from the AISI and AS/NZ standards and from the proposed design equations of Moen and Schafer. From the comparison results, it was found that the AISI and AS/NZ design strengths are only 9% conservative to the test results for plain channels without web holes. While Moen and Schafer equations are conservative by 13% and 47% for axial capacity of CFS back-to-back channels with un-stiffened and edge-stiffened web holes, respectively.","PeriodicalId":51177,"journal":{"name":"Steel and Composite Structures","volume":"40 1","pages":"287"},"PeriodicalIF":4.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66595167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SCS.2021.40.3.421
Xiaoquan Cheng, Xiaoyuan Du, Kun Chen, Maosheng Shu, Xiaodong Liu, Gang Chen
Tensile tests were carried out on the single-lap countersunk composite joints with metallic bushing, and the load-displacement curves, strains and damage morphologies around the bolt hole were measured. A 3D progressive damage finite element model (FEM) was established in ABAQUS/Standard and verified by experimental results. Based on the validated model, tensile performances of the joints were investigated, including damage mechanism analysis of the laminate and the effect discussion of bushing thickness, tightening torque, interference fit size and etc. The results show that metallic bushing can improve ultimate bearing load of the joints. The stress distribution and initial damages caused by assembly around the laminate hole are little affected by bushing thickness. Appropriate tightening torque and interference fit size can improve tensile performances of the joint.
{"title":"Tensile performances of single-lap countersunk composite joints with metallic bushing","authors":"Xiaoquan Cheng, Xiaoyuan Du, Kun Chen, Maosheng Shu, Xiaodong Liu, Gang Chen","doi":"10.12989/SCS.2021.40.3.421","DOIUrl":"https://doi.org/10.12989/SCS.2021.40.3.421","url":null,"abstract":"Tensile tests were carried out on the single-lap countersunk composite joints with metallic bushing, and the load-displacement curves, strains and damage morphologies around the bolt hole were measured. A 3D progressive damage finite element model (FEM) was established in ABAQUS/Standard and verified by experimental results. Based on the validated model, tensile performances of the joints were investigated, including damage mechanism analysis of the laminate and the effect discussion of bushing thickness, tightening torque, interference fit size and etc. The results show that metallic bushing can improve ultimate bearing load of the joints. The stress distribution and initial damages caused by assembly around the laminate hole are little affected by bushing thickness. Appropriate tightening torque and interference fit size can improve tensile performances of the joint.","PeriodicalId":51177,"journal":{"name":"Steel and Composite Structures","volume":"40 1","pages":"421"},"PeriodicalIF":4.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66595318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SCS.2021.40.3.461
Nguyen-Vu Luat, Jiuk Shin, S. Han, Ngoc-Vinh Nguyen, Kihak Lee
This study aims to propose a new intelligence technique of predicting the ultimate capacity of axially loaded circular concrete-filled steel tube (CCFST) columns. A hybrid system based on one of the evolution algorithm – Genetic Algorithm (GA), fused with a well-known data-driven model of multivariate adaptive regression splines (MARS), namely G-MARS, was proposed and applied. To construct the MARS model, a database of 504 experimental cases was collected from the available literature. The GA was utilized to determine an optimal set of MARS's hyperparameters, to improve the prediction accuracy. The compiled database covered five input variables, including the diameter of the circular cross section-section (D), the wall thickness of the steel tube (t), the length of the column (L), the compressive strength of the concrete (fc), and the yield strength of the steel tube (fy). A new explicit formulation was derived from MARS in further analysis, and its estimation accuracy was validated against a benchmark model, G-ANN, an artificial neural network (ANN) optimized using the same metaheuristic algorithm. The simulation results in terms of error range and statistical indices indicated that the derived formula had a superior capability in predicting the ultimate capacity of CCFST columns, relative to the G-ANN model and the other existing empirical methods.
{"title":"Ultimate axial capacity prediction of CCFST columns using hybrid intelligence models – a new approach","authors":"Nguyen-Vu Luat, Jiuk Shin, S. Han, Ngoc-Vinh Nguyen, Kihak Lee","doi":"10.12989/SCS.2021.40.3.461","DOIUrl":"https://doi.org/10.12989/SCS.2021.40.3.461","url":null,"abstract":"This study aims to propose a new intelligence technique of predicting the ultimate capacity of axially loaded circular concrete-filled steel tube (CCFST) columns. A hybrid system based on one of the evolution algorithm – Genetic Algorithm (GA), fused with a well-known data-driven model of multivariate adaptive regression splines (MARS), namely G-MARS, was proposed and applied. To construct the MARS model, a database of 504 experimental cases was collected from the available literature. The GA was utilized to determine an optimal set of MARS's hyperparameters, to improve the prediction accuracy. The compiled database covered five input variables, including the diameter of the circular cross section-section (D), the wall thickness of the steel tube (t), the length of the column (L), the compressive strength of the concrete (fc), and the yield strength of the steel tube (fy). A new explicit formulation was derived from MARS in further analysis, and its estimation accuracy was validated against a benchmark model, G-ANN, an artificial neural network (ANN) optimized using the same metaheuristic algorithm. The simulation results in terms of error range and statistical indices indicated that the derived formula had a superior capability in predicting the ultimate capacity of CCFST columns, relative to the G-ANN model and the other existing empirical methods.","PeriodicalId":51177,"journal":{"name":"Steel and Composite Structures","volume":"40 1","pages":"461"},"PeriodicalIF":4.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66595651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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