Development of an acoustic emission technology package for copvs inspection and recertification

Abstract

Composite overwrapped pressure vessels (COPVs) are used in many applications from 10,000 ft below sea levels to outer space. COPVs are designed to sustain high pressure, carry a large volume of a pressurized gas, and offer excellent weight reduction. These vessels can be subjected to complex modes of failure, some of which are dominated by fiber-bundle breakage (FBB). Due to the safety implications of COPV failure, they are subjected to stringent certification requirements by DOT, ASME and ISO. In this document, we present results of a test campaign designed to collect and characterize acoustic signatures of fiber bundle breakage (FBB), as well as deriving experimentally the “single energy event criteria” (SEEC) required by relevant testing codes and procedures. Testing was performed on type 4 carbon fiber COPVs. Three vessels were tested, aged by pressure cycling to simulate refilling operations for 10 years, and were damaged by high velocity impacts. Hydrostatic tests following DOT requalification test procedures were performed at different stages of the ageing process, and the vessels were loaded to failure. The data set provided signals of FBB on damaged vessels.