College of Engineering

Simon Kaschock-Marenda

College of Engineering

Mechanical Engineering

Faculty Mentor: Dr. Leslie Lamberson

Materials Science & Engineering

Stelios Koumlis Co-Mentor

Relaxation in Military Foams

In the military world, soldiers must avoid injury, both in their training and via the uniform and gear they don. One of the most important areas to protect is the head, susceptible to injury from direct impact, falls or blasts, as well as potential concussions that may result after a trauma. This research focuses on characterizing and optimizing soft open cell polyurethane foams used in current military helmets in order to maximize protection and comfort. This work is performed in collaboration with Team Wendy, a company that supplies helmets to the United States Army and Marine Corps. The foams were examined in compression on a universal load frame in displacement control at varying loading rates and dwell times. Due to their complex nonlinear behavior and heterogeneous microstructure, the amount of force required for the foam to reach equilibrium changes over time, and this data was used determine the different relaxation times upon unloading under various conditions. The findings were analyzed and plotted, and a viscoelastic spring-dashpot model was created to analytically describe their resistance to motion. These results provide insight on how the architecture and composition of protective foams effects performance, which contribute critical information to their optimization for military applications.

College of Engineering

Aditi Bawa

School of Biomedical Engineering, Science, & Health Systems

Biomedical Engineering

Faculty Mentor: Dr. Michele Marcolongo Materials Science & Engineering

Tony Yu Co-Mentor

3T3 Fibroblast Cellular Response on Annealed and Non-Annealed 3D Printed PEEK Spinal Lumbar Fusion Cages

As over 480,000 spinal fusion surgeries are performed each year and the need for implant materials in the biomedical field grows, poly-ether-ether-ketone (PEEK) has proven to be a bioactive material showing potential in the orthopedic area, particularly with spinal fusion cages. Originally used in the aerospace/aviation industries, the semi crystalline polymer with high thermal flexibility is advancing to be used in the biomedical area. Despite this increase in health applications, knowledge about properties of cell adhesion onto PEEK materials is restricted. Previous research indicates that heat treatment increases crystallinity. Therefore, the purpose of this study was to begin the process of seeding fibroblast cells on annealed and non-annealed 3D printed PEEK spinal cages to test cell adhesion because of increased crystallinity. 24 samples of each group were characterized and seeded with 2 groups of 12 annealed and non-annealed cages, each split into textured and smooth surfaces. A live/dead cell assay was performed, and morphology was examined under SEM. This cell study provides the basis for further surface analysis conducted by a collaborative effort between the Drexel Implant Research Center and the Biomaterials Lab Group.