Influence of randomly distributed adhesive properties on the overall mechanical response of metallic adhesively bonded joints

The overall strength of adhesively bonded joints is much dependent on the adhesive properties. In contrast to the ideal situation, real adhesive layers always have non-uniform adhesive properties, which result in inaccurate prediction of the overall mechanical behavior. This paper studies the overall strength of metallic adhesively bonded joints depending on their randomly distributed adhesive properties. A developed numerical method using the cohesive zone model modified by a user-defined subroutine is proposed to realize the randomly distributed adhesive properties. A larger number of computational cases have been carried out for the purpose of obtaining satisfactory statistical results. Finally, stress analysis along the adhesive layer with randomly distributed properties is exhibited. The results show that the overall strength of the joints is sensitive to the randomly distributed adhesive properties. The non-uniformity of the overall strength of the joints obeys the Gaussian distribution, with the statistical parameters close to mean values for the random separation strength. Moreover, the overall strength of the joints has a close relationship with the average stress level of the adhesive layers. The randomly distributed adhesive properties and the corresponding standard deviation should be considered for the reliability and safety of adhesively bonded joints.