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Structural and Constructional Feasibility of
Glass Elements: A Hyperbolic Umbrella

Adviser: Sigrid M. Adriaenssens

Gregor J. Horstmeyer

Civil and Environmental Engineering

“Advice from leaders in your field of research, in addition to the guidance of your adviser, often proves invaluable to your thesis.”

horstmeyer-gregor-john

Engineering students are afforded the luxury of considerable flexibility when choosing their theses. One can do anything from design and build a novel apparatus, undertake seminal research in unexplored areas of study, write a historical perspective on major contributions to a field of study, or anything in between. My thesis involved a physical project in conjunction with a numerical analysis and a written supplement—yes, even though you are an engineer, you do need to show you can form a complete sentence before they’ll hand you a diploma. My project combined three primary interests: engineering, materials science, and art. Ultimately, I designed, fabricated, tested, and analyzed a structural glass canopy.

In the spring of my junior year, I began to search for both an adviser and a topic. As I sat and spoke with Professor Sigrid Adriaenssens, she learned of my prior work with art glass and insisted that we undertake a project involving that surprisingly complex medium. Looking back on those early meetings, I recall the two of us in a frenzy as we brainstormed potential thesis ideas. After a few meetings, we settled on a topic that excited both of us. That brings me to my first point of advice: Investigate something that really excites you intellectually.

Leaving Princeton that summer, I had a general idea of the tasks I needed to accomplish before the start of the fall semester. My adviser and I drew up an initial timeline of objectives. It was necessary to explore the constructional feasibility of the glass canopy and the fabrication of the individual glass elements. Both of these tasks involved experimentation with glass heating and forming techniques.

It did not take long for me to fall victim to Murphy’s Law: What can go wrong will go wrong. Luckily, my lack of full-time summer employment allowed me ample opportunity to sort through all the problems that cropped up. As I troubleshot for answers, I had a glimpse into the world of experimental research. Starting my thesis work the summer before senior year was invaluable for the successful completion of my project. I returned to campus in the fall with a more refined idea of what I was going to be examining, a better idea of the scope of my project, and a long and clear list of questions I needed to address. Point number two: Start early.

Sifting through books, journals, and research papers in search of the answers to your list of questions can feel like an overwhelming task at the beginning. The research process actually adds questions to your list, and answers you think you arrive at are continually refined and updated. In biweekly meetings with my adviser, we were able to examine my work through my ever-changing list of tantalizing questions. No adviser will be upset with you for showing up at a meeting with questions; if anything, this demonstrates that you are actually doing the work. These regular meetings were great learning experiences for both of us. I would arrive with answers (hopefully) to questions posed the previous week and explain my reasoning. We would then discuss any new questions and possible avenues for answers. Point three: Meet often and regularly with your adviser.

There were always problems that we could not work through or that a paper would raise without sufficient explanation. In these instances, I found it to be incredibly helpful to go directly to the source and contact the author. Most academics will be more than happy to try to answer any specific questions you might have about their work. They are both excited and flattered to find that someone else is genuinely interested in their life’s work. Almost everyone was kind enough to give me an e-mail response to my queries, and in some cases I ended up meeting individuals for coffee. Advice from leaders in your field of research, in addition to the guidance of your adviser, often proves invaluable to your thesis. Number four: Be proactive and ask questions of the experts.

I highly recommend not working on your thesis over intersession. I found it really important to take a break and just let things simmer for a while. That meant no new research, no reading; just relax and think. By the time second semester rolled around, I was refreshed and my thoughts were clear. I was ready to tackle the majority of the writing. I met with my adviser, and we reviewed and updated the biweekly schedule deadlines we had planned for the spring. Every few weeks, I would show my adviser a portion of the thesis. She would review it and suggest changes. This allowed me to work on something new while she reviewed something old. When I received her corrections, I was able to incorporate changes she recommended as well as my own editing changes. Slowly, the project was coming together and taking shape. Section by section, and eventually chapter by chapter, the work began to grow more coherent. In late March, I went in for our biweekly meeting and sat down with my most recent time line of objectives and noticed I was almost completely done.

After that meeting, I went back to my room and looked over the first schedule of objectives we had made a year ago. So many things had changed. Comparing the two, I noticed tasks and objectives that were so different they seemed almost contradictory. It was as if each schedule was for an entirely different thesis. This was concrete proof that the thesis process is very dynamic. Ideas evolve and change as you learn new things and you grow sometimes more, or sometimes less, interested in certain aspects of the project. What seemed insignificant at the beginning of the enterprise now occupies 10 pages of text in my thesis. Don’t be surprised if what you end up working on is not what you initially set out to do. My hunch is that is not unusual. The work is going to follow a circuitous path and you are probably going to end up reading a lot about something you had never known about before. As long as the path tracks with what interests and excites you, you will enjoy the research and, ultimately, the entire thesis experience.

In the end, you’re the person who’s going to be up at night buried in books, running between experiments, and debugging code. If you are enthralled in your work and eager to investigate your topic, the project will be incredibly rewarding and well worth those innumerable cups of midnight coffee.

Structural and Constructional Feasibility of
Glass Elements: A Hyperbolic Umbrella

Gregor J. Horstmeyer

Sigrid M. Adriaenssens

Assistant Professor of Civil and Environmental Engineering

“Apart from a single curved glazed dome in a German doctoral study, Gregor was the first to demonstrate the potential these curved glass structures hold.”

A few months into my February appointment as an assistant professor at Princeton University, Gregor Horstmeyer arrived in my office. I had never met him before, but he had learned about me and my research from reading my new website. From this initial conversation, I observed that Gregor had a passion for life. Not surprisingly, I would later find out that the time on his undergraduate thesis was in competition with glassblowing and top-level water polo (he was the 2009 captain of the water polo team!). It struck me that Gregor, a senior in civil and environmental engineering and a glass artist, would be the ideal researcher to investigate and “engineer” a solution for a conundrum that the American glass industry is currently struggling with. In 2006 at the Toledo Museum of Art, the $30 million Glass Pavilion opened as a symbol of America’s “Glass City.” This new structure reflects the legacy of its local glassmakers. One flaw with this image: The curved glass pavilion was completely imported from China, the new world-leading curved glass manufacturer. 

Gregor wholeheartedly turned his hobby into his thesis topic and set about investigating the structural and constructional feasibility of a curved glass inverted umbrella shell. Over the summer vacation, prior to the official start of the thesis research, Gregor spent many nights and days in the heat of his hometown glass workshop in Palo Alto, California, making moulds, melting, slumping and fusing glass, and experimentally optimizing his “recipe” to make curved glass panes. My advice for senior thesis students is to start early. Gregor’s investigations confirmed that novel research never develops according to plan A. His physical experiments turned out to be more difficult than they originally seemed. In the fall semester of his senior year, Gregor unconditionally focused on the complex numerical finite element analysis of his shell, which is really a master’s thesis-level topic. His numerical findings confirmed the structural efficiency of the inverted umbrella shell. The shell proved to be extremely thin and could be constructed of minimal amounts of materials, use little resources, and be a showcase of sustainability. Over the winter break, Gregor completed the shell in Palo Alto and shipped the whole model to Princeton for assembly. 

And then one day there it was. This extremely thin, strong, stable, and beautiful glass curved object was sitting in my lab. Apart from a single curved glazed dome in a German doctoral study, Gregor was the first to demonstrate the potential these curved glass structures hold. He disseminated the findings of his thesis in a publication in a conference held in fall 2010 in Shanghai, the host of the World Expo. But I am ahead of the story. On Class Day, I got to meet Gregor’s parents and brother. I enjoyed the ceremony in particular because I knew that Gregor was going to win not one but two prizes. He rightly won the George J. Mueller Award for “combining high scholarly achievement in the study of engineering with quality performance in intercollegiate athletics” and the Moles Award for “outstanding promise in construction engineering and management.” I enjoyed the close relationship that I formed with Gregor over my first year in Princeton. I think this friendship will last long past graduation.