INTEGRATED PROCESS AND STRUCTURAL MODELING FRAMEWORKS FOR NONLINEAR ANALYSIS OF DISCONTINUOUS LONG-FIBER THERMOPLASTIC COMPOSITES

摘要

Compression molded discontinuous long-fiber (DLF) composites continue to receive great interestrnand successful acceptance in the aerospace industry to replace small and complex-shaped metallicrnparts. However, there is a lack of established design and analysis methods for DLF compositesrndue to a number of factors including random fiber orientations, effects of material flow on fiberrnorientation, limited material data, and nonlinearity in material behavior. Therefore, there is needrnto develop integrated process and structural modeling frameworks in order to accurately predictrnthe performance of DLF parts. Proper processing models and computational tools are required tornpredict the fiber orientation distributions in compression molded DLF components. Since in mostrncases, process simulation and finite element (FE) analysis models and meshes for a DLF part arernnot the same, there is a need to transfer (map) the predicted fiber orientation information from thernprocess simulation model to the corresponding FE model. Then, a proper material model must bernincorporated into the stress analysis, which can predict the nonlinear multi-axial stress-strainrnresponse and all the effective elastic properties of DLF composite material. To that end, this studyrnintroduces effective integration of the predicted fiber orientation information with the nonlinearrnthree-dimensional micromechanical DLF material model for the nonlinear and progressive damagernanalysis of DLF composite materials and structures. The integrated and multi-scale modeling andrnanalysis approach shows very good predictive capabilities for the fiber orientation distributions,rnoverall effective properties, nonlinear response, and ultimate load of DLF composites.