# Torsion

## Helical Springs

When close-coiled helical spring, composed of a wire of round rod of diameter d wound into a helix of mean radius R with n number of turns, is subjected to an axial load P produces the following stresses and elongation:

## Solution to Problem 341 | Torsion of thin-walled tube

## Solution to Problem 332 | Flanged bolt couplings

**Problem 332**

In a rivet group subjected to a twisting couple T, show that the torsion formula τ = Tρ/J can be used to find the shearing stress τ at the center of any rivet. Let J = ΣAρ^{2}, where A is the area of a rivet at the radial distance ρ from the centroid of the rivet group.

## 310 Strength Comparison of Hollow and Solid Steel Shafts of Equal Outside Diameters

**Problem 310**

Show that the hollow circular shaft whose inner diameter is half the outer diameter has a torsional strength equal to 15/16 of that of a solid shaft of the same outside diameter.

## 305 Minimum Diameter of Steel Shaft With Allowable Angle of Twist

**Problem 305**

What is the minimum diameter of a solid steel shaft that will not twist through more than 3° in a 6-m length when subjected to a torque of 12 kN·m? What maximum shearing stress is developed? Use G = 83 GPa.

## Torsion

**TORSION**

Consider a bar to be rigidly attached at one end and twisted at the other end by a torque or twisting moment T equivalent to F × d, which is applied perpendicular to the axis of the bar, as shown in the figure. Such a bar is said to be in torsion.