Aerospace & Mechanical
Engineering

Seminar Announcement

Advanced Manufacturing of Prepreg Composites Structures

Timotei Centea

Research Assistant Professor

Department of Aerospace & Mechanical Engineering
University of Southern California
Los Angeles, CA

Fiber-reinforced composites enable the production of lightweight, high-performance structures in aerospace, marine, automotive, and clean energy sectors. As composites use grows and diversifies, traditional manufacturing methods increasingly restrict structural designs, limit production rates, inhibit applications in new sectors, and conflict with economic and environmental concerns. These challenges motivate research into advanced manufacturing methods for composites. This seminar will focus on the major topic of prepreg processing, describing fundamental and applied research that connects material, structural, and manufacturing scales in order to advance technical, cost and environmental efficiency.

Prepregs, or carbon fiber reinforcement sheets pre-impregnated with an uncured polymer matrix, deposed on a metal tool and cured to produce high-performance structures for aircraft and spacecraft. Most prepreg parts are cured in autoclaves, or pressurized ovens. However, recently, a new generation of vacuum bag-only (VBO) prepregs have enabled out-of-autoclave (OOA) cure in a variety of simpler, lower-cost manufacturing environments. VBO prepreg processing was studied at fundamental and applied levels. First, key relationships between material characteristics, part design, physical phenomena occurring during cure, manufacturing conditions, and structural quality were investigated using advanced imaging methods, in-situ process analysis, and modeling. Then, resulting insights were used to develop science-based defect reduction strategies.

Prepregs can also be used to fabricate high-stiffness, low-density honeycomb core sandwich structures used applications such as aircraft control surfaces, rocket fairings, and marine vessel hulls. The co-cure of honeycomb core structures using autoclave and VBO methods was studied in order to develop an accurate, reliable physics-based process model. The major physical phenomena governing co-cure were clarified and analyzed using a custom-designed lab-scale manufacturing cell capable of accurate control and in-situ diagnostics. Now, these phenomena are being modeled, and integrated into a simulation that will enable structural and manufacturing optimization.

Finally, manufacturing efficiency was advanced by developing science-based technical methods for reducing resource consumption. The use of efficient cure environments based on in-situ diagnostics and multi-zone thermal management was shown to improve control over material state and reduce energy use. Moreover, the reuse of in-process waste for structural applications was studied and validated.

Overall, the seminar will highlight multi-scale, interdisciplinary research that combines fundamental scientific analysis with the development of applied engineering solutions to some of the major challenges facing composites, advanced manufacturing, aerospace, and related fields.


Timotei Centea is a Research Assistant Professor in the Department of Aerospace and Mechanical Engineering at the University of Southern California, and is affiliated with the M.C. Gill Composites Center. He studied mechanical engineering at McGill University in Montreal, Canada, earning Bachelor’s and Ph.D. degrees in 2008 and 2013, respectively. His research interests and expertise center on the fundamental science and applied engineering of the manufacturing of high-performance composites, and aim to advance technical quality and performance, cost-competitiveness and environmental sustainability. Dr. Centea’s work has been supported by personal fellowships as well as research funding from government, institutional and industry sources. His activities have resulted in several awards, including the Best Paper of the 26th Annual Conference of the American Society for Composites (2011).

Wednesday, February 8, 2017
3:30 PM
Seaver Science Library, Room 150 (SSL 150)

Refreshments will be served at 3:15 pm.