Aditi Chattopadhyay

This paper presents a parallelized framework for a multi-scale material analysis method called the generalized method of cells (GMC) model which can be used to effectively homogenize or localize material properties over two different length scales. Parallelization is utlized at two instances: (a) for the solution of the governing linear equations, and (b) for the local analysis of each subcell. The governing linear equation is solved parallely using a parallel form of the Gaussian substitution method, and the subsequent local subcell analysis is performed parallely using a domain decomposition method wherein the lower length scale subcells are equally divided over available processors. The parellization algorithm takes advantage of a single program multiple data (SPMD) distributed memory architecture using the Message Passing Interface (MPI) standard, which permits scaling up of the analysis algorithm to any number of processors on a computing cluster. Results show significant decrease in solution time for the parallelized algorithm compared to serial algorithms, especially for denser microscale meshes. The consequent speed-up in processing time permits the analysis of complex length scale dependent phenomenon, nonlinear analysis, and uncertainty studies with multiscale effects which would otherwise be prohibitively expensive.

A real-time monitoring framework is developed to detect operational anomalies in aircraft engine performance. A historical flight dataset recorded from commercial aircraft is utilized to perform the proposed method. Sampling frequency synchronization and denoise are performed on the flight dataset using signal processing techniques. A robust detection algorithm using the deep neural network is developed to capture flight performance anomalies that show significant off-nominal behavior in engine related and flight dynamic features. The accuracy and efficiency of the proposed monitoring method are validated through a demonstration of anomaly detection in the aircraft engine system associated with dynamic flight behavior.

Recently a novel high-speed/high-yield surfactant-free manufacturing method has been developed for manufacturing of large size buckypaper. In spite of this development, there is no data on the effects of microstructural characteristics on the structural properties of surfactant-free buckypaper based nanocomposites. This investigation examines the effects of the proposed manufacturing procedure on the resultant interlaminar fracture properties of buckypaper based nanocomposites. Buckypaper samples were fabricated using the novel surfactant-free technique. Buckypaper based nanocomposite samples were subjected to mode I, II, and I-II fracture testing in Double Cantilever Beam (DCB ), End Notched Flexure (ENF) and 4-point End Notched Flexure (4ENF), and Mixed Mode Bending (MMB) configurations, respectively. Analysis of the test specimens in terms of mode I energy release rates showed good agreement among Modified Beam Theory, Compliance Calibration, and Modified Compliance Calibration methods. ENF and 4ENF tests gave very consistent crack initiation and propagation results for mode II fracture. The fracture envelope function of the composite and the nanocomposites was developed as a design guideline for nanocomposite materials.