DEVELOPMENT OF A QUICK AND EASY-TO-INSTALL STRAIN MEASUREMENT TOOL FOR BOTH BENDING AND TORSIONAL PIPING STRESS ASSESSMENT

摘要

To assess the stresses on small-bore piping, we have developed a new tool that can be easily installed on a piping surface without adhesive bonding and that measures strains on piping quickly and accurately. This tool, which we call a "strain gauge holder," is patented in Japan. As the tool can contain four strain gauge rosettes, with each rosette comprising three elements, the longitudinal strains and sheer strains can be measured synchronously at any four points precisely 90 degrees apart, with one point in each quadrant. By mockup testing, we confirmed that the measured bending and torsional strains by the holder were almost equivalent to the measured strains by the bonded gauges with adhesive, and that the holder made it possible to synchronously measure all of the strains resulting from the moment of force acting in three axes on the piping by measuring the bending and torsional strains in each quadrant. The strain gauge holder is expected to significantly reduce the pre- and post-working time required for strain measurement and stress assessment of piping in real plants.