Abstract
The mechanical behavior of filled elastomeric (rubber and rubber-like) materials is known to be
incompressible, or nearly-incompressible, hyperelastic and time-dependent, or viscoelastic. This
complex behavior of rubbery materials needs more understanding, and good knowledge is required for
such behavior in order to achieve a good constitutive modeling for better design of a rubber component
for a specific application. This work concentrated on studying the effect of carbon black type on the
mechanical properties of rubbery material characterization. To do this, different tests were performed
on filled rubber with three different kinds of carbon black N326, N375, and N660. All tests were
performed at room temperature. The tests include rheometer tests, hardness tests, tensile tests, specific
gravity tests, compression tests, relaxation test, and cyclic loading tests. Tensile tests were done with
different strain rate, relaxation tests done under different mean strain.
Tensile stress-stretch curves were generated from the test data at strain rate ranging from 10 to 500
mm/min and several transitions associated with strain-induced crystallization were observed in all
materials. The filled rubber became stiffer when the strain rate increased from 10-200 mm/min, and
became more compliant when the strain rate increased from 200 to 500 mm/min.
Hardness and specific gravity tests showed that rubber filled with carbon black N375 is harder and
has specific density more than other two types of filled rubber.The mechanical compression set tests, which performed on rubber with three kinds of carbon black
and found that compression set for rubber filled with carbon black N375 is more than the other two
kinds of filled rubber.
Relaxation stress-time curves were generated from test data at varying mean strain ranging (50% to
200%) from the effective length of the specimen, at constant strain rate (200 mm/min). Generally, it
was observed that the stress reduces with time when the specimen hold at specific strain. This reduction
is faster at strain between 50% and 100% than the strain between 150 to 200% till reaches steady state.
Series of cyclic tension tests were carried out at room temperature on a rubber compound under
strain rate 200 mm/min. All these cyclic strain-controlled experiments showed that the filled rubber
materials, used in the present work are time-dependence with hysteresis. It came out that hysteresis for
rubber with carbon black N375 is more than the rubber with other two kinds of carbon black
