An improved tensile strength and failure mode prediction model of FDM 3D printing PLA material: Theoretical and experimental investigations

3D-printed polylactic acid (PLA) is being increasingly used in practical engineering. In the past, a certain number of models were developed to describe the tensile strength of PLA specimens. However, two opposite tensile strength variation trends with raster angle varying were observed in previous experiments, which cannot be reasonably explained by the current tensile strength models. To resolve this issue, an improved tensile strength and failure mode prediction model is proposed based on the assumption of transversely isotropic material. Corresponding experiments of PLA specimens have also been performed to validate the accuracy of the proposed model. It has been demonstrated that this model could accurately predict the tensile strength and failure mode of 3D printing PLA material. In addition, the opposite strength trends mentioned above with raster variation could also be perfectly explained using the improved prediction model.