UWE Bristol Engineering showcase 2015

Jamie Bustin
BEng Mechanical Engineering
Project Supervisor
Dr John Kamalu
Design and Analysis of a Composite American
Football Helmet
Introduction
Concussions and head injuries are a primary
concern in the sport of American Football
[Langlois, Rutland-Brown & Wald, 2006]. Helmet
advancements have focused on soft inner
protection. Lighter helmet = safer sport [de
Lench, B, 2013]. A composite comparison will be
made due to their general strength-to-weight
ratio advantage. Impact performance is a
concern and will be investigated.
Design
Composites possess superior stiffness
properties compared to current Polycarbonate
Thermoplastics. CLA performed. Stiffness
matrices identified for failure criteria. FEA
designed. Section of helmet used to simplify
node structure. Plate defined. Finest mesh
possible of (n=10) – limited by ABAQUS Student Edition -
used. Force calculated = 470MPa.
Experiments
Ball bearing impact simulated. Tsai-Wu & Tsai-
Hill failure [Kolios & Proia, 2012] occurred in all
composite samples. Polycarbonate
Thermoplastic did not fail. Analysis done
through ANSYS – ABAQUS.
Figure 8.4: Tsai-Wu Failure
Analysis
Figure 8.19: Max Tensile
Stress (Aramid)
Figure 8.5: Max Tensile
Stress (Polycarbonate)
Composites not suitable as football helmet
shell. More advanced hybrid composites show
positive potential.
Project Summary
FEA Comparison of Composites to
Polycarbonate in ballistic impact
performance.
Composite performance not adequate to
make up for strength-to-weight advantages.
Project Objectives
To identify composite laminate ballistic
impact performance through FEA.
To consider existing technology and consult
current literature.
Project Conclusion
Composite weaker despite superior
stiffness characteristics.
Stress distribution key factor.
Hybrid laminate potential.
Figure 8.2: ABAQUS Section
& Projectile
Figure 8.42: Football Helmet
Reference Geometry [CADBase,
2014]