Integrated forming and impact simulation models for rapid liquid composite molded lightweight structures

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The proposed research addresses a critical need to develop an integrated process-to-performance simulation platform to accurately predict the impact response of as-manufactured lightweight liquid composite molded structures. The first challenge in adopting these technologies is the susceptibility of the fabric to localized defects during the rapid preforming stage. Defect severity is heightened by the elevated temperature and high-rate deformation conditions, thus, making it critical to accurately predict the fabric response under these extreme conditions. Maintaining crash safety of corresponding structures poses another key challenge since current crash simulation models for composites neglect important characteristics such as the coupled effect of strain rate and adiabatic heating on the material constitutive response and failure onset. To address these needs, the proposed Discovery Grant research program will: (1) Characterize and model the constitutive response of a unidirectional non-crimp fabric under high temperatures and deformation rates to inform a forming simulation model; (2) Characterize and model the strain rate-dependent constitutive response and failure behaviour of the corresponding composite material; (3) Integrate the constitutive/failure and forming process models into finite element codes used by industry to simulate impact performance of as-manufactured lightweight composite structures. A suite of existing testing infrastructure and optical strain measurement systems coupled with newly designed loading fixtures will be used to characterize for the first time the temperature and rate dependent response of the non-crimp fabric under combined modes of deformation (tension-shear, bending-shear), while enabling monitoring local deformation mechanisms. Experimentally informed constitutive models will be developed and implemented into novel multi-layer fabric forming simulation models. State-of-the-art high speed optical (10 million fps) and thermal imaging systems coupled with dynamic testing devices also available at Waterloo will enable monitoring of temperature and damage evolution in the composite test specimens under a range of strain rates (up to 1000 /s). The new constitutive models and failure criteria will be integrated with the forming simulation model to predict the impact performance of composite structures. The research outcomes will be transferred to industry with high potential to disrupt current crash simulation methods and support widespread adoption of next-generation lightweight vehicle architectures. Beyond commercialization potential and a technological advantage for the Canadian automotive sector, societal benefits will be realized through reduced fuel consumption and CO2 emissions and increased occupant safety in vehicles. A total of ten highly skilled researchers will be trained over the course of the proposed Discovery Grant research program who will be well prepared for the Canadian industry.