Methodology of dry and wet compressibility measurement

Abstract

This paper describes a methodology to obtain and analyse data in composite reinforcement fabric compaction tests in dry and saturated conditions using a standard electromechanical test machine and an indirect thickness measurement method.The main goal is the identification of machine compliance sources and the understanding of its effects in typical compression tests and compression with relaxation stage tests. This methodology was used in the first international compressibility benchmark exercise promoted by NPL (National Physics Laboratory, UK) in the years 2017 and 2018. The methodology accounts for the test setup compliance and evaluates errors in fabric thickness measurements in the range of tens of microns especially during the relaxation phase. Overall, the setup compliance and data analysis strategy proved to have a significant effect on the data if not properly accounted for.