A new device for measurement of permeability evolution under pressure loading: application to CFRP pipes

This paper presents an experimental setup for the measurement of permeability evolution induced by mechanical loading. The experiment consists in ressurizing a pipe-specimen. Internal pressure is used for both loading and permeability measurement. The external face of the pipe is accessible, so that leak paths can be localized and quantified. In order to avoid premature cracking of the specimen due to the device, sealing components were designed using Finite Element Analysis with respect to the stiffness of pipes to be tested. Although current design enables various carbon composite pipes to be tested, it can be easily adapted to other materials. A validation of the design was achieved by measuring permeability on an impermeable pipe. The experimental setup and method were applied to a composite filament wound pipe. Results give substantial quantitative information on the relationship between the number of leak paths and the increase in material permeability.