A crossbow system for high-strain-rate mechanical testing

• Main Authors: Hamdan, S., Swallowe, G. M.
• Format: Article
• Language: English; English
• Published: Institute of Physics 1996
• Online Access: http://psasir.upm.edu.my/id/eprint/38566/1/0001.pdf; http://psasir.upm.edu.my/id/eprint/38566/7/S_Hamdan_1996_Meas._Sci._Technol._7_1068.pdf; http://psasir.upm.edu.my/id/eprint/38566/

This paper describes a technique developed to measure the uniaxial compressive stress - strain properties of polymers at strain rates appropriate to ballistic and impact events over time scales of tens of microseconds using a crossbow as the projectile launch system. The instrument constructed represents a novel development of existing equipment types. The system is used for compression testing giving stress - strain measurements at strain rates of up to 10⁴ s⁻¹ and over a temperature range of 20-200°c . Stress is calculated directly from a measured force obtained from a calibrated pressure bar. Strain is calculated from the sample displacement measured directly from the intensity reduction of a laser-photodiode unit. The crossbow system provides a relatively inexpensive, reliable and compact alternative to a standard Hopkinson bar.