Application of Baushinger effect during prolonged storage in stressed state of elements of structures made of fiber reinforced plastic

Abstract

The problem of the occurrence of irreversible residual deformations is reviewed arising in elements of structures made of carbon fiber reinforced plastic (CFRP) after removing the long and continuous load. These residual deformations impair accuracy of the space structures from CFRP after removing the long load. It is generally known that breaking of the material below the ultimate stress by load cycle reversal in the plastic region is called the Bauschinger effect. Design therefore usually precludes cyclic loading into the plastic region. However, in case of low-cycle loading, the Bauschinger effect can be applied for reduction of the residual deformations in such structures by the pre-loading with opposite sign. CFRP has two plastic deformation stages: the first is ruled by dislocation interactions with the fibers and a real the Bauschinger effect can be observed in repeated tension test. A second stage occurs after 0.6% total strain and is connected with a break of carbon fibers. Examples of the occurrence of residual strain in outer structures from CFRP are shown. A new way of long-term storage in a stressed state of structural elements from CFRP developed on the basis of the Bauschinger effect is presented. The possibility of realization of the proposed method of storage is also shown.