The NAVY seeks microwave curing process modeling and technology demonstration for the cost-effective fabrication of continuous carbon fiber reinforced thermoset composites with reduced cure time and energy consumption. Despite the relatively extensive research work done for the microwave curing of polymer composites, the technology extension for the fabrication of continuous carbon fiber-reinforced thermoset composites (CFRTCs) is challenging to retain the uniform temperature during the curing and eliminate the local heat source-induced damage in the cured parts. To demonstrate the feasibility of manufacturing high-quality CFRTC using microwave radiation with performance-informed process parameters, Global Engineering and Materials, Inc. and collaborators propose to develop a multi-physics modeling approach to simulate the microwave curing process of CFRTC coupons of different thicknesses and layups by including 1) the interaction of electromagnetic, thermal, and chemical mechanisms during the curing; 2) micro-macro coupling to capture the local heat generation and determine the effective modeling parameters for the global curing model; 3) a close loop with the data collected from the in-situ sensor to achieve the desired temperature history within the part; and 4) thermo-mechanical coupling for the residual stress and distortion prediction. In Phase I, the research team will use two materials of CFRTC and fabricate the coupons using the conventional autoclave and microwave curing procedures. A comparative study will be performed based on tensile, flexural, and non-destructive tests to demonstrate the performance and benefits of using the process tailoring of the microwave curing process.
Benefit: The research will result in a novel multiphysics modeling tool that simulates microwave-cured composite parts for process tailoring and optimization. The developed technology will result in a low cost and reduced processing time via the microwave curing approach coupled with in-situ monitoring and digital manufacturing twin to reduce the trial-and-error compared to the conventional autoclave. The developed digital manufacturing twin can be used to rationally select the mode stirrer's microwave source, power, and speed for controlling the electromagnetic fields. In addition, to ensure a uniform temperature field, the local heat generated by each individual fiber can improve the interface bonding between the fiber and matrix. The multiphysics model can be used to describe the electromagnetic field-induced volume heating, cure kinetics, cure history-dependent viscoelastic constitutive relations, micromechanics-based property generation, and progressive damage analysis with a given distribution of fabrication-induced defects. The benefits gained from microwave curing with reduced cure times and reduced energy consumption can open the new door for major composite manufacturers and lead to large-scale real-world component production. This will enable faster design and process optimization and verification, leading to low development costs and adding the values of fabrication of lightweight, high-performance composite structures with reduced non-recurring development costs, recurring production costs, and sustainment costs.
Keywords: Autoclave, Autoclave, electromagnetic-thermal-chemical-mechanical interaction, multiphysics modeling, micro-macro coupling, Mechanical Testing, microwave curing
