Prevent the catastrophic failure of ballistic body armor.
a. Develop a minimally invasive test that quantifies the in-service
properties of ballistic fibers without destroying the protective
vest.
b. Link chemical structure and fiber mechanics to ballistics
performance.
c. Identify chemical mechanisms underlying reduction in chemical
performance (UV & Hydrolysis).
Experimental Approach
Prepare 6 cm gauge length single fiber test (SFT) specimens
with reflecting tape for laser extensometer (i.e., modified-SFT
specimens).
Measure diameter of fibers using optical microscope
Obtained load and strain-to-failure data from modified-SFT.
Deduce modulus, strain-to-failure, and ultimate tensile
strength from modified-SFT data.
Check distribution of data for normalcy using skewness &
kurtosis ratios.
Results
Strain-to-Failure Distribution
Typical Output Data from modified-Single Fiber Test
Specimen
Outputs
Average
Skewness Ratio
Kurtosis Ratio
Strain-to-Failure, %
1.98 ± 0.03
-1.891
0.136
Ultimate Tensile Strength, GPa
2.58 ± 0.31
-1.714
0.225
Modulus, GPa
138 ± 13
-0.711
0.251
Cunniff’s
Equation for Ballistic Performance
parameter is related to ballistic resistance
is the fiber ultimate axial tensile strength
is the fiber ultimate tensile strain
is the fiber density E
is the linear elastic fiber modulus
Customers
NIST Contributors:
Gale Holmes, Kathy Flynn, Steven Roth, Walter McDonough,
Da-Wei Liu, and Chad Snyder.
Characterization and Measurement Group
Polymers Division
Materials Science and Engineering Laboratory
parameter is related to ballistic resistance
is the fiber ultimate axial tensile strength
is the fiber ultimate tensile strain
is the fiber density