## 24.4:

JoVE 核
Mechanical Engineering

JoVE 核 Mechanical Engineering
##### Previous Video24.3: Transmission Shafts: Problem Solving

A bent tube with a circular cross-section subjected to several forces will produce stresses at certain points.

Calculating stresses involves passing a section through specific points and assessing the force-couple system at the centroid, representing internal forces and maintaining the member's equilibrium.

The centric axial force produces normal stresses in the section, while couple vectors cause the member to bend, producing normal stresses. The sum of the normal stresses produced is calculated using Saint-Venant's principles.

The twisting couple and shearing forces generate shearing stresses. The summation of these components is calculated, combined, and then displayed at specific points on the member's surface.

The normal and shearing stresses determine the principal stresses and orientation of the principal planes at these points. The maximum shearing stress at each of these points is then determined.

The superposition principle and Saint-Venant's principle guide stress determination. However, they are valid only if stresses are within the material's proportional limit, deformations from one loading do not affect others, and the analysis section is far from the points of force application.

## 24.4:

When analyzing a bent tube with a circular cross-section subjected to multiple forces, it is crucial to determine the stress distribution in order to maintain structural integrity under varied load conditions.

The process begins by slicing the tube at critical points and analyzing the internal forces and stress components at these sections, focusing on the centroid. Normal stresses, generated by axial forces and bending moments, are either compressive or tensile and vary across the section from the neutral axis to the outer edges.

Shearing stresses, which act tangentially to the section, arise from shear forces and torsional or twisting moments. These stresses provide insights into the overall stress state within the tube. In addition, the calculated stresses are combined to identify the principal stresses at specific points, which are the maximum and minimum normal stresses without shear components.

From these, the maximum shearing stress is determined, a crucial factor in assessing the potential for failure.

Saint-Venant's principle allows for the assumption that stresses become uniformly distributed in sections far from the points of load application. This principle allows the use of superposition to combine effects from different loads, provided the stresses remain within the material's proportional limits. This method ensures accurate predictions of how structural components behave under real-world conditions.