Data acquisition and control for multiple composite life tests

Abstract

Strength durability of composite materials has many current Navy applications including rocket motor cases, pressure vessel for submarine flasks, energy storage for space applications and for pilot ejection seats. The primary effect of composite aging can be characterized by the fiber filament life under constant stress (stress rupture). This thesis develops experimental facilities for parallel testing of fiber filaments in the form of a bundle. A fast data acquisition system records the filaments breakage during load application. The filaments within a bundle sample are maintained at a constant strain level which is automatically adjusted for creep by digital feedback signal from the load of a control sample. A slow speed data acquisition system records filament breakage during long elapse time (days to years). This thesis establishes a nationally unique capability at the Naval Postgraduate School to quantitatively characterize the reliability of composite material.