Separable Operators in Scattering Theory
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Engineering topics
Publications and source records attributed to Gillespie, J..
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For ceramics to be used as structural components in high temperature applications, their fracture toughness is improved by embedding continuous ceramic fibers. Ceramic matrix composite (CMC) materials allow increasing the overall operating temperature, raising the temperature safety margins, avoiding the need for cooling, and improving the damping capacity, while reducing the weight at the same time. They also need to be reliable and available in large quantities as well. In this paper, an innovative rapid prototyping technique to fabricate continuous fiber reinforced ceramic matrix composites is described. The process is simple, robust and will be widely applicable to a number of high temperature material systems. This technique was originally developed at the University of Delaware Center for Composite Materials (UD-CCM) for rapid fabrication of polymer matrix composites by a technique called automated tow placement or ATP. The results of mechanical properties and microstructural characterization are presented, together with examples of complex shapes and parts. It is believed that the process will be able to create complex shaped parts at an order of magnitude lower cost than current CVI and PIP processes.
Monolithic ceramics lack the fracture toughness necessary to be considered for propulsion related applications. To be used for such applications, materials must possess low density, high elastic modulus, a low thermal expansion coefficient, high thermal conductivity, excellent erosion and oxidation/corrosion resistance, and flaw-insensitivity. They will in many cases also be required to possess the ability to be joined, to survive thermal cycling and multi-axial stress states, and for reusable applications the materials must maintain the above attributes after prolonged exposure to extremely harsh chemical environments. The final and possibly most important attributes for these materials are the need to be of low cost and readily available in large quantities.