TESTING METHODOLOGY TO ASSESS A MECHANICAL DAMAGE OF BALLISTIC FIBERS

Jae Hyun Kim*, Walter G. McDonough and Gale A. Holmes

In an effort to develop a minimally invasive testing methodology for monitoring the in-service performance of soft body armor, we modified the protocols in ASTM C1557-03 standard by measuring the fiber diameter at 5 equally spaced locations along a 6 cm gauge length specimen, while specimen construction was modified by placing reflecting tape just outside the specimen gauge length to allow the use of a laser extensometer for directly measuring fiber displacement and hence, strain. The experimental results showed that the modified ASTM C1557-03 testing methodology provides a quantitative approach for monitoring changes in ballistic fiber properties.

We also developed a mechanical folding device to assess the impact of mechanical folding, such as may occur during use, on ballistic fiber properties. After the initial cyclic folding condition for 5500 cycles, fiber tensile strength was decreased about 14%, while modulus was not degraded from the folding.

*The author information

Name: Jae Hyun Kim

Mentor’s name: Gale A. Holmes

Division: Polymers division

Laboratory: Materials Science and Engineering Laboratory

Room/Bldg.: B120/224

Mail stop: 8543

Telephone: 2315

Fax: 3928

E-mail: jaehyun@nist.gov

Membership of Sigma Xi: No

Presentation category: Materials