The Strain Estimation of Statically Determinate Structures Subjected to Forced Displacement by Reference Stress Method

Abstract

It is well known that the inelastic strain accumulation of statically determinate structure subjected to forced displacement is caused by the elastic follow-up due to surrounding elastic region. The author once showed that the relaxation phenomenon of creeping structures during the elastic follow-up can be well estimated by the reference stress method. By applying this result, the author has proposed a simplified method to estimate the creep strain accumulated by the elastic follow-up. It has been shown that elastic follow-up factor can be calculated from the reference stress ratio, which is the ratio of Local Reference Stress and Global Reference Stress. The proposed method was applied to the elastic follow-up of 2-bar model and 2-beam model. For 2-beam model, a simple method has been proposed to estimate the stress-strain relation during the elastic follow-up, and it showed quite good agreement with FEM results. It was also shown that the proposed method can be applied to the plastic strain accumulation due to the elastic follow-up. By comparing with other strain estimation methods such as Neuber's method and Stress Relaxation Locus method, the proposed method was found to be reasonable and precise.