Abstract:
The increasing enrollment of students in higher institutions of learning in Nigeria
demands higher capital expenditures,
which either in some cases are not available or
grossly insufficient, to provide essential machines and equipment for the training of
professional engineers and technologists. Consequently, torsion test is often overlooked
despite its importance
in the investigation
of mechanical
properties
for automobile,
manufacturing, and bio-medical engineering products.
An indigenous
bench-top manual torsion testing machine was developed to
perform pure torsion test on metal rods. The machine provided information on the shear
properties of the materials being tested upon which shear moduli were determined. The
machine was produced predominantly by fabrication method coupled with machining and
casting processes. The various materials of production included mild-steel, aluminium,
cast-iron, tool-steel, and polymer.
Torsion test was conducted, using the machine so developed in this work, on
Aluminium and Brass' specimen with 5 mm diameter, respectively; and 5.5 mm diameter
of Mild-steel. The experimental
shear moduli from the test shown that Aluminum has
23,205.92 N/mm2 (16% less than expected), while Brass has 21,498.06 N/mm2, (43% less
than expected) and Mild-steel has 15,773.10 N/mm2(80%
The results suggested a re-investigation
less than expected).
into the load measuring
unit, as the
applied torque load may be higher than the one being measured. However, a simple
practical approach is being made to demonstrate torsion test for teaching purposes.
