From floods to wildfires, and earthquakes to hurricanes, natural disasters took a catastrophic and costly toll worldwide in 2017. In the U.S. alone, $125 billion in damages were due to Hurricane Harvey, which unleashed devastating floods on southeast Texas and broke rainfall records for a single tropical storm. Such events—in particular, history-making Harvey—led Ian McGough ‘19 and Griffin King ’19 to their Research Science project: a 3D printed clamp attachment that uses the wavelength of a metal corrugated roof to securely attach a tarp.
“Ian is from Houston— from the same neighborhood where some of the worst flooding occurred. That provided the impetus to focus on hurricanes and natural disasters,” explains Griffin. “Our research showed that many in Puerto Rico are still suffering from the aftermath of Hurricane Maria, living with damaged houses and roofs. We discovered that the Federal Emergency Management Agency (FEMA) provided tarps for those in need, but only if you have a wooden roof, because there is no secure way to attach a tarp to metal roofs.”
They also learned that having a wooden roof isn’t always enough: it cannot have sustained more than 50% damage, and anyone asking for help must produce a deed to the land. Even once those criteria are met, there’s no guarantee that FEMA tarps will be secured properly—or at all: several months after Maria, more than two-thirds of Puerto Rican applicants were still waiting for relief.
Addressing the Gaps
Griffin and Ian’s device addresses those gaps. Users simply pull up the clamp—made of acrylonitrile styrene acrylate (ASA), a weather-resistant thermoplastic commonly used in the automotive industry—onto the roof, slide it over to secure the tarp, then let go. Griffin and Ian’s first step was learning how to CAD model, spending a full trimester becoming fluent in Fusion 360 before attempting designs. Their original idea of using screws was discarded early on in favor of a design that didn’t require making holes.
“We came up with a skinny clamp that goes in between the waves of the roof,” says Griffin, who did most of the CAD modeling while Ian focused on research and experimental design. “However, this clamp was too weak. We then incorporated the wave of the roof to make the clamp stronger. Originally we tried to make the curve of the clamp fit exactly to the curve of our roof, spending about a month and a half on this design. In the end, we realized we should make it more universal because not all curves will be the same.”
Through City as Our Campus, Ian and Griffin consulted with Professor Paul Steif, Carnegie Mellon’s associate dean of mechanical engineering. Among Steif’s recommendations: adding half-circle grips to increase friction. “This tweak in the design helped so much,” acknowledges Griffin.
The next challenge was devising a method of preparing ASA plastic, which has a melting point of 221° F, for 3D printing. “To achieve this temperature, most people purchase a $600 heat hood,” notes Griffin. “Instead, we built one using cardboard and insulation which worked just as well.” After gathering data showing the force necessary to pull a tarp from their clamp, they were ready for testing. Says Griffin, “We did two simulation tests where we created a mock roof with our clamps and left it outside for a month. Both were successful.” Griffin and Ian envision a day when FEMA distributes tarps—and their clamp attachments—to people with metal roofs. They hope to apply for a patent. “We plan to see if either of our colleges can help us to continue our design,” says Griffin, who plans to study business or biochemistry at the University of Richmond, while Ian is headed to Northeastern University for chemical engineering. “It’s really rewarding to see something come to fruition, especially after many attempts and redesigns.”