Matching Items (482)

Multi-material 4D Printed Structures with Tunable Hygro-responsive Surface Roughness via Surface Tension-assisted Additive Manufacturing

Description
This study presents a novel approach to 4D printing by employing surface tension-assisted additive manufacturing to fabricate multi-material structures with tunable surface roughness in response to humidity. Poly(ethylene glycol) diacrylate (PEGDA) was selected as the material due to its hygro-responsive and photocurable properties. The photocurable resin was prepared by varying…

This study presents a novel approach to 4D printing by employing surface tension-assisted additive manufacturing to fabricate multi-material structures with tunable surface roughness in response to humidity. Poly(ethylene glycol) diacrylate (PEGDA) was selected as the material due to its hygro-responsive and photocurable properties. The photocurable resin was prepared by varying concentrations of PEGDA, deionized (DI) water, and photoinitiator (PI). The optimized curing and drying times on swelling behavior were studied. The optimal material—mixture of 30 wt% DI water and 0.1 wt% PI—demonstrated the highest swelling ratio while maintaining structural integrity. Vat photopolymerization (VPP) printing method was used to create mesh designs and surface tension-assisted manufacturing was utilized to suspend films of hygro-responsive material. Retentiveness testing showed that circular holes with smaller diameters retained the most material due to uniform tension distribution. The structures exhibited increased surface roughness upon swelling which confirmed the feasibility of the manufacturing methodology. This research suggests the potential for adaptive applications such as responsive grippers or movements with different patterned surface roughness. Future work will focus on improving mechanical properties such as adhesion between different materials and structural brittleness and optimizing fabrication processes through the usage of hydrophobic coatings.
ContributorsYoo, Minju (Author) / Li, Cindy (Thesis director) / Tang, Tengteng (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor) / The Design School (Contributor)
Created2025-05

Effects of Hat Style on Thermal Discomfort in Extreme Heat Conditions

Description
Hats are commonly worn by people in extreme heat conditions, in a variety of colors and styles. In hot environments with high amounts of incident radiation, people often experience significant thermal discomfort, and conventional wisdom leads many of those people to wear hats to alleviate some of their discomfort. Despite…

Hats are commonly worn by people in extreme heat conditions, in a variety of colors and styles. In hot environments with high amounts of incident radiation, people often experience significant thermal discomfort, and conventional wisdom leads many of those people to wear hats to alleviate some of their discomfort. Despite this common practice, the effectiveness of different styles and colors of hats relative to each other has not been thoroughly researched. Hats can have varied impacts on the factors which impact thermal discomfort, including incident radiation, convective heat loss, and evaporative heat loss from sweat. The difference between styles and colors of hats can cause them to have different interactions with these methods of heat transfer, which lead to variance in the total impact on thermal discomfort. This research was conducted in order to create an experimentally justified recommendation for hat selection to limit thermal discomfort in hot and sunny areas.
ContributorsLyons, Caitlyn (Author) / Rykaczewski, Konrad (Thesis director) / Joshi, Ankit (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2025-05