Prediction of Elastic Properties for Thermoplastic Composites In Situ Manufactured Using Laser‐Assisted Automated Fiber Placement

ABSTRACT The mesoscale finite element simulation method based on the Representative Volume Element (RVE) can predict the elastic properties of composites according to the dimension and distribution characteristics of fibers and voids. Nevertheless, affected by the non‐uniform distribution of fibers and voids as well as crystallization behavior in thermoplastic composite specimens in situ manufactured via laser‐assisted automated fiber placement, the RVE generated by conventional fiber generation algorithms fails to accurately forecast the elastic properties of in situ manufactured specimens. In this paper, on the basis of experimentally observed microstructures of in situ manufactured specimens, a subregional random fiber generation algorithm and a gradient random void generation algorithm were proposed. A mesoscale finite element model was established to predict the elastic properties of in situ manufactured thermoplastic composites. The results of the nearest neighbor distribution function, pair distribution function, and Ripley's K function verify that the fiber distribution of the generated RVE was in good agreement with the microstructure of the in situ manufactured specimens. Compared with autoclave‐consolidated specimens, the transverse elastic modulus and out‐of‐plane shear modulus of in situ manufactured specimens decrease by 13.38% and 18.54%, respectively. The proposed method provides a foundation for predicting the properties of thermoplastic composite structures manufactured by laser‐assisted automated fiber placement and shows potential applicability to thin‐shell composite structures.