Investigation of the Defect Effects on the Load-Carrying Capacity of Butt Joints: A Numerical Study

Determining the behavior of joints under a specific load and estimating the damage potential is essential for ensuring the durability of joints in engineering structures. Defects might occur at the adhesive layer, which causes a reduction in the durability of joints. This work aims to examine the effects of the defect presence, defect volume fraction, defect position, and random distribution of defects at the adhesive layer on the durability of the butt joint. A finite element (FE) model of the butt joint was constructed using the commercially available FE software Abaqus/Standard. The validation of the FE model was conducted by comparing its results with experimental finding reported in existing literature. Numerical and experimental results showed strong agreement, with relative errors of 2.46% and 2.95% at peak force and displacement at peak force, respectively. Defect presence significantly influences the durability of the butt joint. Defect volume fraction and defect location are the dominant parameters affecting the durability of the butt joint. The square defects at the center of the bonding layer, with volume fractions of 0.05, 0.10, and 0.15, lowers the peak force by 5.08%, 10.56%, and 15.73%, respectively. When the defect is positioned at the center of the bonding layer, adhesive failure starts at the edges of the defects. However, relocating the defect from the center to the left or upper side of the bonding layer results in adhesive failure initiation at the corresponding edges of the adhesive. Random defect distribution in the adhesive layer doesn’t affect joint durability.