Characterizing the Unique Properties of Natural Fiber Composites Nondestructively
Board Location: #87
Discipline: Technology and Engineering
Subcategory: civil/mechanical/industrial
Session: 3
David Warren Jr. - Elizabeth City State University
NASA’s Project SUMAC (SUstainability Manufacturing of AirCraft) is just starting to investigate ways to transition from carbon fiber based composite fibers and resins to naturally derived fibers and sustainably-resourced thermoplastic resins. Aircraft manufacturers need sustainably derived thermoplastic composites in order to build environmentally friendly aircraft so that the environmental impacts of air commercial transport is reduced. This research develops non-destructive test methods and structural health monitoring approaches for these materials, aiming to determine what nondestructive evaluation techniques are most suitable for characterizing these natural fiber composites. Considering the non-conductive and dielectric properties of these natural fiber composites, identifying effective NDE methods can pose a challenge.
This study investigates these composites using Terahertz Time Domain Spectroscopy, Laser Doppler Vibrometry, an LCR Meter, and ultrasonic techniques to characterize acoustic and electric properties of the Flax Fiber composites. The research also involves optimizing the scanning equipment’s parameters in order to achieve the ideal setting for repeatability of data collection. Equipment and software include MATLAB, LabVIEW, SolidWorks, Ultrasonic Transducers, Pulser Receiver, Terahertz systems, Laser Doppler Vibrometer, LCR Meter, and 3D Printing.
A Terahertz Time Domain Moisture Experiment identified that Terahertz scanning can effectively detect moisture content in natural fiber composites. A Terahertz distance offset experiment identified the optimum scanning distance a material should be analyzed away from the lens regarding maximum amplitude intensity. A laser doppler vibrometry experiment identifies how guided waves propagate and interact with the natural fiber composite using non-contact vibrational methods. An impedance, inductance, and capacitance test on a wooden tongue depressor identifies the harmonic resonance, dielectric properties, and electrical properties of natural wooden fibers. These investigations successfully identified effective nondestructive evaluation methods, and characterized the unique properties of natural fiber composites. Future work includes identifying other potential nondestructive evaluation techniques for natural fiber composites, potentially integrating inkjet printed sensors onto the natural fiber composites to conduct inductance, impedance, and capacitance measurements using an array of sensors, and to improve the manufacturing process in efforts to enhance the material properties of the natural fiber composites.
Funder Acknowledgement(s): MUREP, NC/VA Alliance, NSF
Faculty Advisor: Akbar Eslami, aeslami@ecsu.edu
Role: As a Nondestructive evaluations science branch intern at NASA Langley, I established nondestructive test methods and structural health monitoring approaches for natural fiber composites, characterized acoustic and electric properties, gained familiarity with ultrasonic, Laser Doppler Vibrometer, and terahertz approaches, and supported test development for various application of nondestructive evaluation.