Mechanical Performance of Adhesive Connections in Structural Applications

Abstract

Adhesive bonding is an excellent candidate for realising connections for secondary structures in structural applications such as offshore wind turbines and installations, avoiding the risk and associated welding problems. The strength of the adhesive layer is an important parameter to consider in the design process it being lower than the strength capacity of the bonding material. The presence of defects in the adhesive materials undoubtedly influences the mechanical behaviour of bonded composite structures. More specifically, the reduction in strength is more pronounced as the presence of defects (voids) increases. For this reason, a correct evaluation of the presence of defects, which can be translated into damage parameters, has become essential in predicting the actual behaviour of the bonded joints under different external loading conditions. In this paper, an extensive experimental programme has been carried out on adhesively bonded connections subjected to Mode I and Mode II loading conditions in order to characterise the mechanical properties of a commercial epoxy resin and to define the damage parameters. The initial damage parameters of the adhesive layer have been identified according to the Kachanov–Sevostianov material definition, which is able to take into account the presence of diffuse initial cracking.

Application of Organo-Modified Silica Nanoparticles to Improve the Load-Bearing Capacity of Bonded Joints of Dissimilar Steel Substrates

“…An important part of this effort is the use of new lightweight materials in vehicle structures, including high-strength steel, aluminium, magnesium, and polymer composites. A practical example of combining unequal grades of steel is the B-pillar design, where AHSS and mild steel are combined to achieve a compromise between mechanical performance, light weight, and material cost [1,2]. There is a move towards parts composed of different grades and thicknesses of materials, to joining materials of a different material nature (metals + composites), which requires mastery of different joining techniques [3][4][5][6][7][8][9][10][11].…”

Heterogeneity of Adhesive Joint Properties

“…Changes in the adhesive joint strength should be associated with an increased quantity of imperfections in the adhesive material occurring in the larger volume (thickness) of the adhesive joint. The inclusion of initial cracking in the design of the adhesive joint numerical model makes it possible to improve the accuracy of the results of numerical calculations compared to experimental results [19,20].…”