Author

Ankit Patel

Date of Award

Spring 2019

Document Type

Open Access Thesis

Department

Electrical Engineering

First Advisor

Mohammod Ali

Abstract

Thermoplastic composites are in great demand for current and future manufacturing of aircraft and automotive industries. Induction heating and welding of thermoplastic composite laminates is of great significance. The non-contact method of heating and welding is being adopted in aircraft parts, engine parts, and turbine parts manufacturing among many other things. This thesis performs simulations and analyses of Electromagnetic (EM) induction heating of thermoplastic composites materials.

The induction heating and welding of thermoplastic composites in the presence of a susceptor alloy (called Monel) consisting of 67% nickel and 27% copper is studied using a Finite Element Analysis (FEA) software. A primary current carrying coil was excited using 500A of current at 292 kHz frequency, which exposed the Monel susceptor underneath it. The EM fields created by the primary coil caused induced current in the Monel mesh, which caused losses. Temperature rise in the material is synonymous to the losses in the material. The I2R losses in the Monel material was used as the basis to calculate the temperature rise in the material. Simulation results clearly show the heating patterns on the Monel mesh, less in the center and high on the edges. Location-based temperature increases due to I2R losses are calculated which show significant heating and welding potentials. The result obtained from the simulation was validated using an experiment. Measured temperature increase showed the reading of 40 and 43.9 degrees respectively (thermocouple and IR camera). These numbers compare favorably with the simulated temperature increase of 38.97 degrees C.

Also, the induction heating of Carbon fiber reinforced composites (CFRC) were simulated and studied. The results obtained from the simulation explain that fiber orientation and the presence of resin are two critical parameters that affect the output e.g. the solid loss. Due to the challenges in the high aspect ratio of the models, i.e. very small fiber diameters and many fibers within a very small dimension only smaller sized models were simulated. Furthermore, instead of a circular cross-section a polyhedron cross-section for the fiber model was considered to successfully complete the simulations. It was found that simulation models containing fibers oriented in 0 and 90 orientation yielded higher solid loss than fibers oriented in the same direction. It was observed that for fibers with resin present in between them yielded far greater solid loss compared to no-resin cases, especially for very small separation distances between fibers. Especially, for the 0, 90 orientation of fibers and in the presence of resins solid loss was nearly 200 times that for fibers with 0,0 orientation and that were at short distance from one another.

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