The Torsional Rigidity of a Rectangular Prism

Using the membrane analogy, in 1934 Timoshenko derived the torsional rigidity of a rectangular prism of isotropic material as a function of its material shear modulus, width and thickness. However, he did not consider the energy conservation criterion, as it could be either unnecessary or replaced b...

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Main Authors: Cho-Liang Tsai, Chih-Hsing Wang, Sun-Fa Hwang, Wei-Tong Chen, Chin-Yi Cheng
Format: Article
Language:English
Published: MDPI AG 2022-06-01
Series:Mathematics
Subjects:
Online Access:https://www.mdpi.com/2227-7390/10/13/2194
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author Cho-Liang Tsai
Chih-Hsing Wang
Sun-Fa Hwang
Wei-Tong Chen
Chin-Yi Cheng
author_facet Cho-Liang Tsai
Chih-Hsing Wang
Sun-Fa Hwang
Wei-Tong Chen
Chin-Yi Cheng
author_sort Cho-Liang Tsai
collection DOAJ
description Using the membrane analogy, in 1934 Timoshenko derived the torsional rigidity of a rectangular prism of isotropic material as a function of its material shear modulus, width and thickness. However, he did not consider the energy conservation criterion, as it could be either unnecessary or replaced by other criteria in Timoshenko’s process. To confirm the correctness of Timoshenko’s solution, this work re-derives the torsional rigidity by considering all the equilibrium conditions, boundary conditions, symmetric and anti-symmetric conditions of displacement and stress, the energy conservation criterion, and even the energy minimization criterion. Using the TSAI technique, exact solutions for the displacements, strains, stresses and the torsional rigidity are derived perfectly. The derived torsional rigidity is in a completely different form from that derived by Timoshenko and is numerically identical. Interestingly, the solutions derived in this work verify that, when the values of the width and thickness of the rectangular prism are swapped, the value of the torsional rigidity remains the same, which makes perfect sense physically but is not discussed in Timoshenko’s process or any other research. This work presents a procedure considering all the mathematical details and the results remain correct when the width and thickness of the prism swap. This fact makes perfect sense physically, though has never been expounded before in Timoshenko’s or other researchers’ solutions, either for torsional rigidity or for the induced shear stresses and displacements.
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spelling doaj.art-b38bdf59aad3411390f6d7f1945849792023-12-03T14:11:42ZengMDPI AGMathematics2227-73902022-06-011013219410.3390/math10132194The Torsional Rigidity of a Rectangular PrismCho-Liang Tsai0Chih-Hsing Wang1Sun-Fa Hwang2Wei-Tong Chen3Chin-Yi Cheng4Department of Civil and Construction Engineering, National Yunlin University of Science and Technology, Yunlin 64002, TaiwanCollege of Future, Bachelor Program in Industrial Projects, National Yunlin University of Science and Technology, Yunlin 64002, TaiwanDepartment of Mechanical Engineering, National Yunlin University of Science and Technology, Yunlin 64002, TaiwanDepartment of Civil and Construction Engineering, National Yunlin University of Science and Technology, Yunlin 64002, TaiwanDepartment of Mechanical Engineering, National Yunlin University of Science and Technology, Yunlin 64002, TaiwanUsing the membrane analogy, in 1934 Timoshenko derived the torsional rigidity of a rectangular prism of isotropic material as a function of its material shear modulus, width and thickness. However, he did not consider the energy conservation criterion, as it could be either unnecessary or replaced by other criteria in Timoshenko’s process. To confirm the correctness of Timoshenko’s solution, this work re-derives the torsional rigidity by considering all the equilibrium conditions, boundary conditions, symmetric and anti-symmetric conditions of displacement and stress, the energy conservation criterion, and even the energy minimization criterion. Using the TSAI technique, exact solutions for the displacements, strains, stresses and the torsional rigidity are derived perfectly. The derived torsional rigidity is in a completely different form from that derived by Timoshenko and is numerically identical. Interestingly, the solutions derived in this work verify that, when the values of the width and thickness of the rectangular prism are swapped, the value of the torsional rigidity remains the same, which makes perfect sense physically but is not discussed in Timoshenko’s process or any other research. This work presents a procedure considering all the mathematical details and the results remain correct when the width and thickness of the prism swap. This fact makes perfect sense physically, though has never been expounded before in Timoshenko’s or other researchers’ solutions, either for torsional rigidity or for the induced shear stresses and displacements.https://www.mdpi.com/2227-7390/10/13/2194energy conservationrectangular prismtorsional rigidityTSAI technique
spellingShingle Cho-Liang Tsai
Chih-Hsing Wang
Sun-Fa Hwang
Wei-Tong Chen
Chin-Yi Cheng
The Torsional Rigidity of a Rectangular Prism
Mathematics
energy conservation
rectangular prism
torsional rigidity
TSAI technique
title The Torsional Rigidity of a Rectangular Prism
title_full The Torsional Rigidity of a Rectangular Prism
title_fullStr The Torsional Rigidity of a Rectangular Prism
title_full_unstemmed The Torsional Rigidity of a Rectangular Prism
title_short The Torsional Rigidity of a Rectangular Prism
title_sort torsional rigidity of a rectangular prism
topic energy conservation
rectangular prism
torsional rigidity
TSAI technique
url https://www.mdpi.com/2227-7390/10/13/2194
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