A Stress Analysis of a Thin-Walled, Open-Section, Beam Structure: The Combined Flexural Shear, Bending and Torsion of a Cantilever Channel Beam

Channels with three standard symmetrical sections and one asymmetric section are mounted as cantilever beams with the web oriented vertically. A classical solution to the analysis of stress in each thin-walled cantilever channel is provided using the principle of wall shear flow superposition. The l...

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Main Author: David W. A. Rees
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Applied Sciences
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Online Access:https://www.mdpi.com/2076-3417/15/15/8470
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author David W. A. Rees
author_facet David W. A. Rees
author_sort David W. A. Rees
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description Channels with three standard symmetrical sections and one asymmetric section are mounted as cantilever beams with the web oriented vertically. A classical solution to the analysis of stress in each thin-walled cantilever channel is provided using the principle of wall shear flow superposition. The latter is coupled with a further superposition between axial stress arising from bending and from the constraint placed on free warping imposed at the fixed end. Closed solutions for design are tabulated for the net shear stress and the net axial stress at points around any section within the length. Stress distributions thus derived serve as a benchmark structure for alternative numerical solutions and for experimental investigations. The conversion of the transverse free end-loading applied to a thin-walled cantilever channel into the shear and axial stress that it must bear is outlined. It is shown that the point at which this loading is applied within the cross-section is crucial to this stress conversion. When a single force is applied to an arbitrary point at the free-end section, three loading effects arise generally: bending, flexural shear and torsion. The analysis of each effect requires that this force’s components are resolved to align with the section’s principal axes. These forces are then considered in reference to its centroid and to its shear centre. This shows that axial stress arises directly from bending and from the constraint imposed on free warping at the fixed end. Shear stress arises from flexural shear and also from torsion with a load offset from the shear centre. When the three actions are combined, the net stresses of each action are considered within the ability of the structure to resist collapse from plasticity and buckling. The novelty herein refers to the presentation of the shear flow calculations within a thin wall as they arise from an end load offset from the shear centre. It is shown how the principle of superposition can be applied to individual shear flow and axial stress distributions arising from flexural bending, shear and torsion. Therein, the new concept of a ‘trans-moment’ appears from the transfer in moments from their axes through centroid G to parallel axes through shear centre E. The trans-moment complements the static equilibrium condition, in which a shift in transverse force components from G to E is accompanied by torsion and bending about the flexural axis through E.
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spelling doaj-art-aac4aa2cf62e4471a0a953e7e4ee3fc32025-08-20T03:02:56ZengMDPI AGApplied Sciences2076-34172025-07-011515847010.3390/app15158470A Stress Analysis of a Thin-Walled, Open-Section, Beam Structure: The Combined Flexural Shear, Bending and Torsion of a Cantilever Channel BeamDavid W. A. Rees0College of Engineering, Design and Physical Sciences, Brunel University of London, Uxbridge UB8 3PH, UKChannels with three standard symmetrical sections and one asymmetric section are mounted as cantilever beams with the web oriented vertically. A classical solution to the analysis of stress in each thin-walled cantilever channel is provided using the principle of wall shear flow superposition. The latter is coupled with a further superposition between axial stress arising from bending and from the constraint placed on free warping imposed at the fixed end. Closed solutions for design are tabulated for the net shear stress and the net axial stress at points around any section within the length. Stress distributions thus derived serve as a benchmark structure for alternative numerical solutions and for experimental investigations. The conversion of the transverse free end-loading applied to a thin-walled cantilever channel into the shear and axial stress that it must bear is outlined. It is shown that the point at which this loading is applied within the cross-section is crucial to this stress conversion. When a single force is applied to an arbitrary point at the free-end section, three loading effects arise generally: bending, flexural shear and torsion. The analysis of each effect requires that this force’s components are resolved to align with the section’s principal axes. These forces are then considered in reference to its centroid and to its shear centre. This shows that axial stress arises directly from bending and from the constraint imposed on free warping at the fixed end. Shear stress arises from flexural shear and also from torsion with a load offset from the shear centre. When the three actions are combined, the net stresses of each action are considered within the ability of the structure to resist collapse from plasticity and buckling. The novelty herein refers to the presentation of the shear flow calculations within a thin wall as they arise from an end load offset from the shear centre. It is shown how the principle of superposition can be applied to individual shear flow and axial stress distributions arising from flexural bending, shear and torsion. Therein, the new concept of a ‘trans-moment’ appears from the transfer in moments from their axes through centroid G to parallel axes through shear centre E. The trans-moment complements the static equilibrium condition, in which a shift in transverse force components from G to E is accompanied by torsion and bending about the flexural axis through E.https://www.mdpi.com/2076-3417/15/15/8470thin-wall cantilevershear centrecentroidwarping restraintflexural bendingtransverse shear
spellingShingle David W. A. Rees
A Stress Analysis of a Thin-Walled, Open-Section, Beam Structure: The Combined Flexural Shear, Bending and Torsion of a Cantilever Channel Beam
Applied Sciences
thin-wall cantilever
shear centre
centroid
warping restraint
flexural bending
transverse shear
title A Stress Analysis of a Thin-Walled, Open-Section, Beam Structure: The Combined Flexural Shear, Bending and Torsion of a Cantilever Channel Beam
title_full A Stress Analysis of a Thin-Walled, Open-Section, Beam Structure: The Combined Flexural Shear, Bending and Torsion of a Cantilever Channel Beam
title_fullStr A Stress Analysis of a Thin-Walled, Open-Section, Beam Structure: The Combined Flexural Shear, Bending and Torsion of a Cantilever Channel Beam
title_full_unstemmed A Stress Analysis of a Thin-Walled, Open-Section, Beam Structure: The Combined Flexural Shear, Bending and Torsion of a Cantilever Channel Beam
title_short A Stress Analysis of a Thin-Walled, Open-Section, Beam Structure: The Combined Flexural Shear, Bending and Torsion of a Cantilever Channel Beam
title_sort stress analysis of a thin walled open section beam structure the combined flexural shear bending and torsion of a cantilever channel beam
topic thin-wall cantilever
shear centre
centroid
warping restraint
flexural bending
transverse shear
url https://www.mdpi.com/2076-3417/15/15/8470
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