Strength and failure assessments of 3D printed PLA single lap joints: Experimental and numerical analysis

•Strength and failure mechanisms of 3D printed PLA SLJs are examined.•Computational and experimental approach presents comprehensive investigation.•Novel SLJ with toothed interface confirmed significantly higher strength, toughness.•Geometric shape of toothed interface SLJs are graded for maximizing failure load. In this paper, fused deposition modelling (FDM), is either used exclusively or in conjunction with adhesive bonding to manufacture single lap joints (SLJ). The design aspects of 3D printed SLJs are studied to assess their strength and failure mechanisms. Novel tooth-shaped interface joints are developed, leading to stronger and tougher joints. The uniaxial characteristics of Polylactic acid (PLA) were determined through testing on dog-bone samples. Subsequently, numerical models were developed to simulate the strength and failure modes of SLJs, followed by experimental testing. A parametric study was conducted to establish the influence of geometric parameters of tooth-shaped interface joints on failure load of tailored SLJs. Compared to baseline SLJs produced purely by 3D printing, the best performing tooth-shaped interface SLJs exhibit increased strength, failure strain, and toughness of ≈30%, ≈52%, and ≈130% respectively. Computational and experimental results confirm that SLJs with tooth-shaped interfaces can improve strength and failure strain.