KARAGOZIAN & CASE, INC. — Department of Defense SBIR Phase I: AF151-187

Description

ABSTRACT: The Karagozian & Cases team proposes to develop a predictive toolkit for the mechanical and physicochemical behaviors of ceramic matrix composites (CMCs) up to failure, especially for extreme thermo-mechanical loadings. The toolkit will consist of a constitutive model, computer software, and material model parameters. The proposed CMC model will be based on the thermodynamics of irreversible processes with internal state variables approach and will account for the inelastic, damage and fracture behaviors as well as the degradation and healing scenarios induced in CMCs in high temperatures. The mechanical part of the CMC model will lend itself into an ABAQUS/STANDARD user material Software based on a local loop made of nested fixed-point and NewtonRaphson iterations, while its physicochemical part will be implemented into MATLAB software using a mixed analytical/numerical formulation. A link will be established between both implementations. The CMC model parameters will be determined for a self-healing SiC/SiC CMC developed by the SAFRAN Group and other CMCs that may be of interest to the U.S. Air Force. Several examples, including the prediction of the service life and the understanding of self-healing mechanisms, will be used to validate the CMC model. BENEFIT: The outcome of this proposal is the development of a robust ABAQUS/STANDARD user material (UMAT) software to predict the inelastic, damage and fracture behaviors as well as the healing/degradation mechanisms of CMC materials and structures, especially in extreme thermo-mechanical environments. We will also provide a set of CMC material model parameters for the self-healing SiC/SiC CMC, developed by the SAFRAN Group and other CMCs of interest to the U.S. Air Force.