STEEL - Materials for Civil and Construction Engineers - page 118

FIGURE 3.16 Torsion test apparatus.

30

200

150

P

20

100

10

50

R

0 0

0 0.002 0.004 0.006 0.008

Shear strain

FIGURE 3.17 Typical shear stress-strain diagram of steel (ASTM
E143). Copyright ASTM. Reprinted with permission.

where

T = torque

r = radius

pr 4

J = polar moment of inertia of the specimen about its center,

2

for a

solid circular cross section.
of twist in radians
length

u = angle

L = gauge

The test method is limited to materials and stresses at which creep is
negligible compared with the strain produced immediately upon loading. The