06/02/2023
By Joshua Lee

The Francis College of Engineering, Department of Mechanical Engineering, invites you to attend a Master's Thesis defense by Joshua Lee on "Characterization of Graded Adhesives and Textile Knits."

Candidate Name: Joshua Lee
Degree: Master’s
Defense Date: 06/15/2023
Time (from/to): 10-11 a.m.
Location: Southwick 240 (SOU-240)

Advisor: Scott E. Stapleton, Ph.D., Department of Mechanical Engineering, University of Massachusetts Lowell

Committee Members:
1) Prof. Christopher J. Hansen, Department of Mechanical Engineering, University of Massachusetts Low
2) Prof. Daniel F. Schmidt, Materials Research and Technology, Luxembourg Institute of Science and Tech
3) Prof. Jay H. Park, Department of Plastics Engineering, University of Massachusetts Lowell

Brief Abstract:
In engineering applications, such as aerospace, bolts and rivets are a common use for structural joints. However, stress concentrations are formed around the holes where the bolts and rivets were drilled when certain loads are applied. Thus, this will lead to damage and delamination if the adherends are fiber reinforced composite materials. Adhesively bonded joints are then preferred because the load is distributed through the adherend and the requirement to drill into the composite is no longer needed. Adhesive properties were graded through categorized radiation exposure to induce secondary-cross linking and would then increase the stiffness of the adhesive locally. End-Notched Flexure tests were then performed to characterize the mode-II in plane shear fracture toughness as a function of radiation exposure. Recent advances in material science were found in textiles, however little is known about how the textiles’ structure alone changes the mechanical responses. Plain knit fabrics were extensively studied, though no further experimental investigations have been performed to explain and predict the biaxial mechanical response. Thus, standardized knits are used to explore the characterization of mechanical responses by undergoing biaxial tests. Constant cyclic loading is performed to find the mechanical characteristics of the standardized knit structures.