On Mooney-Rivlin Constants for Elastomers

The Mooney-Rivlin constitutive equation for rubber is W= C1(I1-3)+C2(I2-3) where material constants C1 and C2 must be determined through tests. The constant C1 can be determined by uniaxial tension or compression tests; however, C2 cannot be determined accurately by uniaxial tension or compression tests. In order to determine C, biaxial tests must be performed. A biaxial test, inflation of a circular 2membrane, is presented in detail here for determining both C1 and C2 .