Elastic-plastic analysis of perforated thin strips of a strain-hardening material

Abstract

The paper considers the problem of determining the elastic-plastic strain and stress distribution that occurs in thin perforated strips of a strain-hardening material when the applied stress is increased monotonically from the elastic region of loading to values producing an impending plastic flow. The values of elastic and plastic components of strains were determined by using the birefringent coating method complemented with the electrical analogy method which yields the strain distribution normal to the surface of the strips. The components of stresses were evaluated by introducing the usual assumptions of generalized plane stress to a material conforming to the Mises yield condition and the incremental flow-type stress-strain relations. Two cases were considered of thin perforated strips, where the ratio δ of the diameter of the hole d to the width of the strip L was taken equal to one third and one half. The mode of evolution of plastic enclaves was studied and the influence of the ratio of the diameter of the hole to the width of the strain and stress distribution was determined.