Stress-strain state analysis of the polymer insulator adhesive bonding of a railway overhead system with a metal insulation displacement contact under torsion

Abstract

Based on consideration of a simplified model, an analytical solution to the problem of adhesive bonding stress-strain state estimation of a polymer insulator of the railway overhead system with a metal insulation displacement contact under torsion is presented. The polymer insulator is made of unidirectional epoxy resin-based fibreglass with the ratio of binder and filler 0.3:0.7. The solution is obtained by considering the adhesive bonding incremental element equilibrium. The influence of such parameters as the thickness of the adhesive layer, the adhesive bonding length, and the modulator of shearing of the metal insulation displacement contact on the adhesive bonding stress-strain state change has been investigated. It is shown that the greatest tangential stresses in the adhesive layer occur at the point of entry of the fibreglass rod into the steel termination, and the length of the zone of relatively large tangential stresses in the adhesive layer is a small value compared to the length of the adhesive bonding. During the research of influence of glue layer thickness on the greatest tangential stresses in a glue layer it is received, that at accepted parameters of a glue bonding increase of thickness of a glue layer in ten times leads to reduction of the greatest tangential stresses in a glue layer approximately in three times. An increase in the length of the adhesive bonding, all other things being equal, has little noticeable effect on the greatest tangential stresses in the adhesive layer. The same conclusion can be reached by varying the shear modulus of the metal termination. Thus, replacement of steel insulation displacement contact with copper or aluminium insulation displacement contact practically does not change the value of the greatest tangential stresses in the adhesive layer.