Engineering of a CMC aeronautical muffler

Abstract

This work explores the feasibility of adopting an LSI produced C/SiC composite to build an aeronautical Auxiliary Power Unit system muffler. The study first covers the experimental material characterization through tensile and compressive tests. The material properties are characterized also after exposing the samples to an oxidizing atmosphere, that is typical for the proposed application. The material response is characterized by significant non-linearities and a pseudo plastic response, which were numerically modeled using a Drucker-Prager model. The detailed design of the muffler is described and verified, for different loading conditions, using a Finite Element model. Finally, a full-scale prototype is produced and assembled, thus proving the technological feasibility of the design. The manufacturing phase required to study and understand the phenomena that were leading to defects in the proposed closed axial symmetric shape, and to implement suitable technological solutions in order to get an acceptable prototype.