Assessment of the adhesion strength of composite curved elements

Abstract

Modern composites have good strength properties. But insufficient adhesive strength often leads to the delamination of a coating. The Poisson’s ratio, modulus of elasticity, and thermal coefficient of linear expansion are of particular importance among the characteristics of materials that determine different properties of the coating and metal. The ratio of metal and coating thicknesses is also important. The work suggests that the temperature deformations associated with the polymerization of a coating influence the process of delamination of the reinforced polymer coating. Evaluation of the potential of the proposed calculated dependencies was carried out according to the results of experiments. A polymer coating consisting of «Sprut-Plus» adhesive composition and a filler (T-11-GVS-9 glass fabric) was applied to a surface of St.3 steel. For experimental studies, the reinforced polymer coating was kept in water and machine oil for 100 days. The thickness of the coating was taken to be 10 mm, and the thickness of the metal - from 3 to 6 mm. Calculated and experimental dependences of radial stresses on the relative thickness of the polymer coating are obtained. An increase in radial stresses at the interface between the layers of the metal and the reinforced polymer coating after holding the composite material in water has been established; it does not exceed 10%. Analysis of the results showed that the destruction of the adhesive metal-polymer joint is more likely than that of the polymer-polymer adhesive joint. In addition, the radial stresses are at their maximum at the interfaces. Prospects for further research in this direction are associated with express methods of repairing metal structures of complex configuration. It is necessary to increase the efficiency and reliability of calculations of curved elements consisting of metal with a reinforced polymer coating. This can be achieved by a combination of experimental and theoretical research.