Compressive Properties - ISO 604
Compressive Modulus
The ratio of compressive stress to compressive strain in the linear region of the stress-strain curve between strain values of 0.05% and 0.25%. Compressive modulus is calculated using the formula:
Ec=(σ2-σ1)/(ε2-ε1)
where ε1 is a strain of 0.0005,
ε2 is a strain of 0.0025,
σ1 is the stress at ε1,
and σ2 is the stress at ε2.
Compressive Stress
The compressive stress carried by a test specimen at a specified strain during a compression test.
Testing is performed on either rectangular or cylindrical specimens. The specimen is placed between the platens of a universal testing machine and compressed at a constant rate of either 1 mm/min for modulus testing or strength testing of brittle materials, or 5 mm/min for strength testing of ductile materials. A stress-strain plot is used to extract the compressive strength and the compressive modulus.