Families of adhesives and characterization of a structural bond: Complete file

Efficient research work, technological progress, cutting-edge technical achievements, commercial approaches have succeeded in making adhesives penetrate into everyday life.

If the collage was already well known in Egyptian Antiquity, in particular for associating sheets of papyrus joined to each other to form a writing roll (Department of Egyptian Antiquities of the Louvre Museum), ancestor of the form of the book until at II^e century following JC, before the arrival of the codex, then of the current book, he knows in the XX^e and 21^e century the strongest expansion of modern assembly technologies: there is no technical field that can ignore the importance of assembly by gluing.

Papers, cardboards, fabrics, leathers, plastics, woods, metals, minerals are now experiencing countless new applications thanks to bonding.

The aerospace industry as a great precursor of technological progress, strong in its authority, paved the way for the entire construction industry.

The first steel bonding applications date back to the early 1970s and are experiencing significant growth despite a strong tradition for welding and mechanical assemblies.

Due to the evolution of the characteristics of adhesives with improved mechanical properties and adapted to the materials used, which has generated a multitude of industrial applications, bonding rightly occupies a place of choice among the most modern techniques of ‘assembly.

The article presented in the semi-finished products section of this treatise concerns structural bonding by adhesive applied to assemblies whose modulus of elasticity of the substrates is high compared to that of the adhesive polymer. Adhesive products (or glues) of animal or vegetable origin are a priori not taken into account.

To analyze and predict the behavior of a bonded assembly of this type, we do not have until now a single theory capable of interpreting the phenomena during bonding nor a synthetic approach integrating the choice of designs, products and processes.

Particular attention is paid to the intrinsic study of the adhesive and that of the single lap bonded joint stressed in tension and shear. These elements make it possible in particular to study the phenomena of adhesion and resistance in hot and humid environments with a view to designing an optimal bonded assembly ensuring a guarantee of durability, appreciated in particular by manufacturers.

The objective of this article is to define the main structural adhesives used to date and to determine a reproducible procedure for the implementation and characterization of control specimens, in order to identify the fundamental parameters related to the substrate, the coating and the adhesive that condition the stress resistance values.

Readers wishing to deepen their knowledge of structural bonding can consult the Bonding section of the Mechanical Engineering treatise on Engineering Techniques.