Decrease in stress occurring with lapse of time in a body in constant strain or deformation.
Decrease in stress in a material subjected to prolonged constant strain at a constant temperature. Stress relaxation behaviour is deter-mined in a creep test. Data often is presented in the form of a stress vs. time plot. Stress relaxation rate is the slope of the curve at any point.
The very important property of some sealants to be able to be subjected to extended periods of constant stress and internally relax to more easily accommodate the continual stress. Silicone is one notable product that does not have this ability.