Structural integrity of bonded joints

Evaluation of the adhesive strength of a bonded joint is of paramount importance in aeronautical engineering and also in the space applications in the rocket science area. From mathematical point of view it is not a simple problem, since it involves mechanics of fracture applied not to a single solid body, but to two bodies with dissimilar material moduli and other properties common in the theory of continua, such as Poisson ratio, shear modulus and the inherent cohesive strength. To address the task of evaluation of the adhesive strength an energy approach analogous to that of Griffith (1921) has been applied. Certain specific examples pertaining to various geometrical configurations have been considered and the closed form solutions have been found. The fundamental assumption of this work is the idea that although the energy approach to fracture may not be exact, yet it provides a valuable physical insight and an excellent approximation for the exact solutions to problems, which are not usually susceptible to rigorous mathematical treatment.