Relaxation test

The relaxation test is meant to obtain viscous properties of the rubber, in this case, based on Prony model. The device for relaxation test is the same as that for the uniaxial test. The first step of the test is to stretch the specimen up to the specified strain, and the device then keeps the strain constant for some period. During that period, the tensile stress is recorded. That stress is gradually decreased in the function of time, while the strain is kept constant. This phenomenon is called as relaxation of the rubber. Having higher damping, the variation between initial and final stress during the constant strain period is greater.