Lateral–Torsional Buckling of Cantilever Steel Beams under 2 Types of Complex Loads

Cantilever steel beams are an essential structural element in civil engineering fields such as bridges and buildings. However, there is very little research on the critical moment (<i>M</i><sub>cr</sub>) of cantilever beams subjected to a concentrated load (CL) or a combinati...

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Main Authors: Yong Cai, Angyang Ling, Xiaoyong Lv
Format: Article
Language:English
Published: MDPI AG 2023-05-01
Series:Applied Sciences
Subjects:
Online Access:https://www.mdpi.com/2076-3417/13/10/5830
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author Yong Cai
Angyang Ling
Xiaoyong Lv
author_facet Yong Cai
Angyang Ling
Xiaoyong Lv
author_sort Yong Cai
collection DOAJ
description Cantilever steel beams are an essential structural element in civil engineering fields such as bridges and buildings. However, there is very little research on the critical moment (<i>M</i><sub>cr</sub>) of cantilever beams subjected to a concentrated load (CL) or a combination of concentrated load and uniformly distributed load (CUDL) when the concentrated load is not limited to the free end. Therefore, the focus of the current paper is the calculation of <i>M</i><sub>cr</sub> for cantilever steel beams under CL and CUDL. This paper proposes a program and a simple closed-form solution for <i>M</i><sub>cr</sub> that are applicable to the elastic buckling analysis of cantilever I-beams under CL and CUDL. Based on the Rayleigh–Ritz method, a matrix equation and the corresponding procedure about <i>M</i><sub>cr</sub> under CL and CUDL are derived by using infinite trigonometric series for the buckling deformation functions. The value of <i>M</i><sub>cr</sub> and the corresponding mode of buckling can be obtained efficiently by considering the symmetry of the section, the ratio of two load values and the load action position. Experimental results and finite element calculations validate the numerical solutions of the procedure. A closed-form solution for <i>M</i><sub>cr</sub> is derived according to the assumption of a small torsion angle and the specific values of each coefficient in the closed-form solution of <i>M</i><sub>cr</sub> are calculated by the proposed procedure. The results show that the procedure and closed-form solution for <i>M</i><sub>cr</sub> presented in this paper have a high degree of accuracy in calculating the <i>M</i><sub>cr</sub> of the cantilever beam under CL and CUDL. The deviations between the results calculated by the proposed procedure and data from existing literature are less than 8%. These conclusions are capable of solving the calculation problem of <i>M</i><sub>cr</sub> for cantilever beams under CL or CUDL, which are both significant load cases in engineering. The study provides a reference for the design of cantilever steel beams.
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spelling doaj.art-b320b06b1d2847cb9f7cf33bb495bbe02023-11-18T00:16:19ZengMDPI AGApplied Sciences2076-34172023-05-011310583010.3390/app13105830Lateral–Torsional Buckling of Cantilever Steel Beams under 2 Types of Complex LoadsYong Cai0Angyang Ling1Xiaoyong Lv2School of Civil Engineering, Central South University, Changsha 410075, ChinaSchool of Civil Engineering, Central South University, Changsha 410075, ChinaSchool of Civil Engineering, Central South University of Forestry and Technology, Changsha 410004, ChinaCantilever steel beams are an essential structural element in civil engineering fields such as bridges and buildings. However, there is very little research on the critical moment (<i>M</i><sub>cr</sub>) of cantilever beams subjected to a concentrated load (CL) or a combination of concentrated load and uniformly distributed load (CUDL) when the concentrated load is not limited to the free end. Therefore, the focus of the current paper is the calculation of <i>M</i><sub>cr</sub> for cantilever steel beams under CL and CUDL. This paper proposes a program and a simple closed-form solution for <i>M</i><sub>cr</sub> that are applicable to the elastic buckling analysis of cantilever I-beams under CL and CUDL. Based on the Rayleigh–Ritz method, a matrix equation and the corresponding procedure about <i>M</i><sub>cr</sub> under CL and CUDL are derived by using infinite trigonometric series for the buckling deformation functions. The value of <i>M</i><sub>cr</sub> and the corresponding mode of buckling can be obtained efficiently by considering the symmetry of the section, the ratio of two load values and the load action position. Experimental results and finite element calculations validate the numerical solutions of the procedure. A closed-form solution for <i>M</i><sub>cr</sub> is derived according to the assumption of a small torsion angle and the specific values of each coefficient in the closed-form solution of <i>M</i><sub>cr</sub> are calculated by the proposed procedure. The results show that the procedure and closed-form solution for <i>M</i><sub>cr</sub> presented in this paper have a high degree of accuracy in calculating the <i>M</i><sub>cr</sub> of the cantilever beam under CL and CUDL. The deviations between the results calculated by the proposed procedure and data from existing literature are less than 8%. These conclusions are capable of solving the calculation problem of <i>M</i><sub>cr</sub> for cantilever beams under CL or CUDL, which are both significant load cases in engineering. The study provides a reference for the design of cantilever steel beams.https://www.mdpi.com/2076-3417/13/10/5830cantilever steel beamlateral–torsional bucklingtotal potential energy equationcombined loadcritical moment
spellingShingle Yong Cai
Angyang Ling
Xiaoyong Lv
Lateral–Torsional Buckling of Cantilever Steel Beams under 2 Types of Complex Loads
Applied Sciences
cantilever steel beam
lateral–torsional buckling
total potential energy equation
combined load
critical moment
title Lateral–Torsional Buckling of Cantilever Steel Beams under 2 Types of Complex Loads
title_full Lateral–Torsional Buckling of Cantilever Steel Beams under 2 Types of Complex Loads
title_fullStr Lateral–Torsional Buckling of Cantilever Steel Beams under 2 Types of Complex Loads
title_full_unstemmed Lateral–Torsional Buckling of Cantilever Steel Beams under 2 Types of Complex Loads
title_short Lateral–Torsional Buckling of Cantilever Steel Beams under 2 Types of Complex Loads
title_sort lateral torsional buckling of cantilever steel beams under 2 types of complex loads
topic cantilever steel beam
lateral–torsional buckling
total potential energy equation
combined load
critical moment
url https://www.mdpi.com/2076-3417/13/10/5830
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AT angyangling lateraltorsionalbucklingofcantileversteelbeamsunder2typesofcomplexloads
AT xiaoyonglv lateraltorsionalbucklingofcantileversteelbeamsunder2typesofcomplexloads