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Adding particles and fibers to the adhesive layer is a method suggested to improve the stress distribution and to increase the strength and toughness of adhesive joints. In this paper, the effects of adding the metal fibers and also the reduction of fiber horizontal distance on distribution of peel stress and shear stress toward longitudinal and transverse directions were studied using finite element analysis. The obtained results showed that the reduction of the horizontal distance between the metal fibers in the longitudinal direction improves the distribution of the peel stress and shear stress and leads to a significant reduction in their maximum values in the joint length with respect to the non-reinforced adhesive. Meanwhile, reduction of the horizontal distance between the metal fibers in the transverse direction first degrades the peel stress and then improves it. Despite the trend observed for the peel stress with the transverse direction, the distribution of the shear stress with reduction of the horizontal distance between the metal fibers becomes more uniform and the maximum values of shear stress regularly decreases in the joint length due to considerable load sharing of the metal fibers in the adhesive layer. In addition to the analyses carried out on the distribution of stress in the joints length, the distribution of peel stress and shear stress were also investigated in joint width, which was indicative of a significant effect of the metal fibers in the transverse configuration.

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In this paper, the static stiffness and strength as well as fatigue life of adhesively bonded single lap joint (SLJ) are numerically studied using the cohesive zone model (CZM). In order to simulation of the SLJ using mixed-mode bi-linear CZM, the failure behavior of adhesive in modes II and III is considered the same. Fatigue damage propagation is simulated through scripting USDFLD Subroutine in ABAQUS/Standard. Static stiffness and strength and fatigue life obtained in this study are consistent with experimental results available in literature. Then, the effect of geometric parameters including overlap length, substrate thickness, and tapered substrates are investigated. The obtained results reveal that the increase of the overlap length would lead to increase the static strength and fatigue life prediction. While increasing substrate thickness results improved fatigue life, there are no a known relation between the static strength and substrate thickness due to the changes of the loading modes. Tapered substrates have also positive effect on the strength and fatigue life because of more compatible rotations. Therefore, to improve the strength and fatigue life of a SLJ, authors suggest greater overlap length and thickness along with tapered substrates.