The Influence of Dissipated Stresswork on the Rupture of Materials

Summary

When the stress deviator in a body upon which external forces act exceeds a certain limit, the body looses its continuity and breaks. This phenomenon of rupture implies the appearance of new surfaces to the several parts into which the body is converted, and therefore the increase of surface energy. The source of such additional surface energy is in the stored potential energy which has been produced by the elastic part of the stresswork (w _Se ). Therefore that part of the stresswork which in the course of deformation has been dissipated by either plastic (frictional) or viscous resistance (w _sd ) does not contribute to rupture. Dissipation of the stresswork accordingly increases the breaking strength of the material. If a material such as a Newtonian liquid has no formelasticity, it will be sheared indefinitely, but never break. (Rupture under isotropic tension will occur in every material, due to the fact that every material has volume-elasticity.) Actually, any real liquid possesses some formelasticity. This has been proved to exist in lubricating oils, and such oil can suffer rupture in a journal bearing.