COMPARISON OF THE YIELD FUNCTIONS FOR MICROPOLAR MEDIA USING A CYLINDRICAL SAMPLE MODEL

Abstract

The article discusses different yield functions extended to the case of micropolar media in order to investigate the effect of local plasticity in metals. The paper is concerned with the inhomogeneous stress-strain state obtained within the frame of the micropolar continuum approach for a cylindrical specimen under distributed couple stress on its lateral surface. The case corresponding to specimen tension is considered. Plastic strains prove to arise near the border of the specimen, while the material continues to behave elastically. According to the results, it is necessary to take into account couple stresses to clarify what happens in the area near the border when the size of this area is comparable to the size of the structure inhomogeneity.