Date of Award

2018

Degree Type

Thesis

Degree Name

Master of Science in Mechanical Engineering and Applied Mechanics

Department

Mechanical, Industrial and Systems Engineering

First Advisor

Arun Shukla

Abstract

This research investigates the effects of shock loading on a composite structure’s compressive residual strength. The research develops a methodology for evaluating and quantifying such damage using non-destructive imaging technologies, and develops a prediction equation for compressive residual strength of the damaged composite structure.

Experiments and imaging of Cyply 1002 glass-fiber/epoxy laminate panels were conducted at the University of Rhode Island (URI) and the Naval Undersea Warfare Center Division, Newport (NUWCDIVNPT), respectively. Controlled air blast experiments were conducted using the shock tube at URI’s Dynamic Photomechanics Laboratory (DPML), inducing non-catastrophic damage on the panels. 3D Digital Image Correlation (DIC) was used to measure the transient response of the composite panels during blast loading, as well as material characterization and residual strength experiments. To evaluate the shock-induced damage in each composite panel, Terahertz (THz) and Flash Infrared Thermography (FIRT) were used to non-destructively obtain through-thickness images of the specimens before and after damage.

The results of the research show that THz and FIRT imaging can be used to quantify internal damage in a composite laminate after shock loading. Additionally, residual strength experiments show that increased shock damage causes a reduction in compressive residual strength. An analytical relationship was developed using MATLAB to predict the residual strength of a composite panel as a function of a combined damage parameter.

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