Date of Award
Fall 12-10-2021
Access Type
Dissertation - Open Access
Degree Name
Doctor of Philosophy in Aerospace Engineering
Department
Aerospace Engineering
Committee Chair
Sirish Namilae
First Committee Member
Marwan S. Al-Haik
Second Committee Member
Daewon Kim
Third Committee Member
Alberto Mello
Fourth Committee Member
Eduardo Rojas
Abstract
The ubiquitous usage of polymer matrix composites in many applications demands a comprehensive understanding of composite interfaces and processing induced residual stresses, which critically affect both the manufacturing processes and the deformation mechanisms. Processing induced residual stresses are often responsible for causing warping, delamination, and dimensional instability in composite structures. This research includes new in-situ experimental approaches, cure cycle design, interface modification, and thermomechanical modeling for developing a fundamental understanding of the cure kinetics during composite manufacturing. Strains, ply-movement, and formation of defects are observed in-situ using digital image correlation (DIC) during the autoclave cure cycle for the first time. The processing-induced defects in the composite are further characterized by X-ray micro-computed tomography (micro-CT). A non-destructive method is developed to calculate residual stresses using DIC Strains in combination with temperature-dependent moduli obtained from Dynamic Mechanical Analysis (DMA) and Classical Laminate Theory (CLT). Cure cycle design with interrupted cure and interface modification with ZnO nanorods experiments are developed to reduce these processing- induced residual stresses and thereby increase laminate strength. The experimental results are validated through thermomechanical modeling of the composite cure process.
Scholarly Commons Citation
Chava, Sandeep, "Kinematics of Inter-Ply Interfaces In Composite Manufacturing" (2021). Doctoral Dissertations and Master's Theses. 635.
https://commons.erau.edu/edt/635