Explanation

When the total deformation (or displacement) of a component or sample is constant, the process of stress decreasing with time due to the continuous transformation of elastic deformation to plastic deformation is called stress release. This phenomenon often occurs in springs, bolts, and other pressure fitting components. Although it can also occur at room temperature, it becomes obvious with the increase of temperature. It is essentially a creep. test of stress relaxation is to measure the change of stress with time under the condition of constant temperature (generally at high temperature) and constant displacement, and take the residual stress after the specified time as the criterion of materials resistance. It is not only related to the nature and structure of materials, but also to the test temperature and initial deformation. The test can be used to determine the initial stress required for the bolted parts to maintain sufficient tightness when they are used for a long time under high temperature, predict the reduction of the sealing degree of the gasket, the reduction of the spring elasticity, and the stability of the reinforcement in the prestressed concrete.

Classification