Tuesday  |  Virtual Track 1  |  09:36 AM–09:48 AM

#11963, Ballistic Performance Evaluation of Carbon Graphite Foam (CGF) And Nanoparticle-Kevlar (SNK) Composites Using Compressed-Air Guns

Owing to their exceptional thermal and mechanical properties, materials such as Carbon Graphite Foam (CGF) and Silica Nanoparticle-Treated Kevlar (SNK) are of interest in many multifunctional applications. It is therefore desirable to evaluate their ballistic performance in comparison to baseline foams or untreated Kevlar, for instance. In this study, we evaluate CGF
and SNK composite samples using compressed-air guns (CAG). Two CAGs are used in this study, a large-bore (2.5") and a small-bore (0.357") CAG. Firstly, an improved analytical model was developed to predict the projectile's velocities for the CAGs. This Loss-Compensated Model (LCM) builds upon existing analytical models such as the Adiabatic, Lagrange, and the Pidduck and Kent models by incorporating clearance leakage, improved surface friction, and air drag effects. The CAGs were calibrated using projectiles of multiple weights in order to establish the cylinder pressure versus projectile velocity characteristics. Velocity measurement was accomplished using a high-speed camera. Correlation with predictions from analytical models demonstrates that the LCM gives excellent agreement with the high-speed camera (HSC) measurements in
comparison to the other models. For CAGs with a higher degree of losses due to projectile or barrel imperfections, the LCM provides a significant improvement in projectile velocity prediction. After achieving confidence on velocity measurement by HSC via LCM model, ballistic tests are performed on CGF and SNK. CGF composite samples were constructed from modular
foam blocks with Aluminum face sheets bonded together using an epoxy adhesive. Baseline Aluminum foam composite samples were also constructed using the same procedure. For the SNK samples, a multistep treatment process was established that allows for a more uniform distribution of the nanoparticle in the fabric. Neat Kevlar K745 fabric was considered as the baseline. 10%, 30%, and 40% by weight of silica nanoparticle addition using a 80-100 nm particle-size, water-based colloidal
solution were considered for the SNK samples. Multiple samples were made and tested for the same test case. Both nonpenetrative and penetrative test cases were considered. For the CGF, the depth of backing signature measurement as per NIJ Standard 0101.06 is considered as the performance parameter. A plasticine clay witness block was used as the backing material.

Muhammad Ali Bablu   Oklahoma State University
James M. Manimala   Oklahoma State University