Torsion of Thin Box Sections — Lesson 4

This lesson covers the concept of shear stresses and their application in various fields. It explains how shear stresses act at different points of cross-section under the action of torsion. The lesson further delves into the use of thin box sections in various applications such as aircraft wings and missing tools. It discusses how these sections respond to torsion, especially in the case of aircraft when the wind thrust is not uniformly distributed. The lesson also introduces the Bredt-Batho formula, which relates the torque capacity to shear flow and the area of the section. It concludes with an illustrative example of a square box section and a round section, comparing their maximum shear stress for the same torque and the same angle of twist.

Video Highlights

01:57 - Discussion on the effects of torsion on different sections and the need to evaluate the magnitude of the stresses
06:29 - Introduction to the concept of shear flow and its application in stress analysis
15:11 - Detailed explanation of the Bredt-Batho formula and its use in calculating torque and shear flow
24:38 - Application of the Bredt-Batho formula in solving problems related to shear stress and angle of twist per unit length
33:40 - Comparison of shear stress in square box sections and round sections under the same torque and angle of twist
44:11 - Analysis of sections with multiple segments using the Bredt-Batho formula and equilibrium equations

Key Takeaways

- Shear stresses act at different points of cross-section under the action of torsion.
- Thin box sections are widely used in various applications such as aircraft wings and missing tools.
- The Bredt-Batho formula relates the torque capacity to shear flow and the area of the section.
- The shear stress in a section can be evaluated using some approximate methods.
- The shear stress and angle of twist per unit length for a given torque can be calculated using the Bredt-Batho formula.