Governing Differential Equation of Shell Buckling: Donnell's Equation — Lesson 1

This lesson covers the equations of equilibrium for a cylindrical shell, specifically focusing on Donnell's equation. It explains how to solve this equation to find the critical load of an axially loaded cylindrical shell. The lesson also discusses the classical solution or equilibrium approach and the boundary conditions. It further elaborates on the displacement function and its implications. The lesson concludes with an analysis of the post-buckling behavior of axially compressed cylinders, highlighting the impact of initial imperfections on the maximum load a cylinder can support.

Video Highlights

00:32 - Explanation of Donnell's equation and its application to find the critical load of an axially loaded cylindrical shell
07:01 - Simplification of the equation and introduction of new variables
13:35 - Derivation of the condition for the critical stress to not depend on the length of the cylinder
21:17 - Discussion on the post-buckling behavior of axially compressed cylinders

Key Takeaways

- Donnell's equation is used to express the equations of equilibrium for a cylindrical shell.
- The critical load of an axially loaded cylindrical shell can be found by solving Donnell's equation.
- The displacement function is assumed to satisfy the boundary conditions.
- The post-buckling behavior of axially compressed cylinders is influenced by initial imperfections.
- Near perfect specimens have experimental buckling loads very close to theoretical critical loads.