Professor and dean, University of Regina, Regina,
graduate student, University of Regina, Regina,
Pages: 15 Published: Jan 1993
Inelastic strains in notched mechanical components and structures can be predicted with reasonable accuracy using the generalized local stress strain (GLOSS) method of analysis. The GLOSS diagram is essentially a normalized stress-strain plot of a “local” region that is subjected to greater inelastic strains as compared to the “remaining” region. Inelastic response of the local region due to plasticity and creep is simulated by artificially lowering the stiffness of the nominally inelastic region. Thus, inelastic strains at the root of a notch can be estimated on the basis of two linear elastic finite element analyses per point on the load-notch strain curve.
The theory underlying GLOSS analysis essentially relates the inelastic multiaxial stress redistribution in the local region to the uniaxial stress relaxation process. The varying degrees of interaction between the local and remaining regions, which are characterized by the “constraint parameter,” enable the determination of inelastic strains when used in conjunction with the cyclic stress strain curve.
The GLOSS method of analysis can be used to estimate inelastic effects for realistic notch geometries and component loadings. The method can be applied in a routine manner to a range of inelastic zone sizes. The incorporation of an Irwin's type of correction to the plastic zone enables reasonably accurate determination of the inelastic notch strains for the purpose of low-cycle-fatigue evaluations. The GLOSS method is applied in this paper to several geometric configurations of practical interest.
low-cycle fatigue, strain concentration, relaxation modulus, constraint parameter, follow-up
Paper ID: STP24814S