NASA Glenn Research Center
August 29 – December 20, 2019
As an intern in the Icing Branch, I worked on developing experimental techniques and analysis tools to better understand the mechanics of the interface between ice and stainless steel. The project I was assigned consisted of preforming digital image correlation (DIC) on samples generated in the Icing Research Tunnel (IRT). The introduction of DIC to the experiment would allow for the displacement field over the entire sample to be measured. In addition to conducting the experiments, I would need to develop the tools to analyze the data. By measuring the full-field displacement on the surface of the sample, the ice behavior can be better understood and mechanical properties can be determined.
Describe what you did during the internship.
Over the 17 weeks, I spent at the NASA Glenn Research Center I was involved with several different aspects of the research conducted by the Icing Branch. I was able to expand on the experimental techniques available for the study of fundamental ice physics by conducting DIC. The first task I was given involved in preparing the necessary equipment for the tests I would be conducting. By having an active role in preparing the necessary systems for my experiment, I developed a better understanding of the wiring and circuits that I would be using. This proved quite useful when damage happened to the data collection system and repairs had to be made. During this time I developed the necessary surface preparation steps that the samples would need to undergo prior to the experiment. To conduct accurate DIC, the surface of the sample must have a random speckle pattern applied so the software can measure the surface displacement to sub-pixel accuracy. After the surface of the sample was patterned, I would conduct the experiment and capture high definition images of the sample surface over the duration of the experiment. Commercial software was used to correlate the images captured during the experiment and the software calculates the displacement fields for each image. In order to analyze the data, I developed analysis codes that would take the displacement data and calculate the interfacial shear strain. As my internship progressed, the capabilities of the analysis were increased to include the Young’s Modulus of the ice. The cycle of experiment and analysis development was repeated over the course of my internship to improve the process. I was also able to support several test campaigns in the Icing Research Tunnel (IRT). The first two campaigns I was a part of involved me collecting samples to be used for studying the grain structure of the ice. By studying the grain structure, new insights into the growth and properties of the ice can be determined. The third campaign I was a part of involved generating the samples I would use for my experiments. Some samples were tested immediately and others were stored in order to study the effects of annealing time on the strength of the interface.
Did you achieve your goals? What were the results and conclusions?
I was successful in completing the goals given to me for my internship. Based on the techniques for applying the speckle pattern I developed, high-quality DIC data was acquired and analyzed. I was able to accurately calculate the shear strain along the interface and measure the Young’s Modulus of the sample. The data gathered during my internship will be used to improve the analysis of older data and inform the design of new experiments. The samples collected during the first two IRT campaigns are being used to determine how wind tunnel conditions affect ice grain structure.
Describe positive lessons learned from this experience:
During my internship, I worked with an experimental technique that was unknown to the majority of the Icing Branch. This meant that to present my work at meetings, I would need to clearly communicate technical details about the methods I was using. Over the course of my internship, I was fortunate to work with people who helped me grow as a communicator and presenter. The capstone presentation of my internship was a one-hour technical talk and I was able to effectively communicate my research to people who worked in vastly different fields. Every person I interacted with during my time at NASA Glenn, from the IRT technicians to the branch chief, were all welcoming and helped me to make the most of my internship.
Describe negative lessons learned from this experience:
It is difficult for me to say I have a negative lesson to take away from my internship. While the research was challenging and sometimes progress seemed slow, the experience was overwhelmingly positive. With the help of the people I worked with challenges were always viewed as the opportunities for growth, both personal and professional.