Shear Modulus - ISO 537

Shear modulus is the ratio of shear stress to shear strain. Testing is performed using a torsional pendulum. A test specimen of uniform cross-section is clamped at both ends, one end fixed and the other to a weighted disc that acts as an inertial member. The system is put into motion and the oscillation period and amplitude is measured and plotted as a function of time. The shear modulus is derived from the amplitude vs. time plot.

Torsion Pendulum

For isotropic materials the shear modulus can be related to the tensile modulus with the formula:
G = E / [2(1+ν)]
where G is the shear modulus,
E is the tensile modulus,
and ν is the Poisson's ratio of the material.

ISO 537 has been discontinued and was replaced by ISO 6721-2.