Traceable measurement of mechanical parameters of double bending beam force transducers according to EN ISO 376

This paper discusses the traceable determination of mechanical parameters of monolithic double bending beam spring elements that are applied as force transducers and load cells in the mass and force metrology. Thereby it mainly deals with the measurement of the specific values creeping, reversibility, repeatability, zero error and interpolation error which are defined in applicable regulations such as the EN ISO 376 standard or the OIML recommendation R 60. Our determination of those parameters is based on an interferometric deformation measurement of a loaded binocular shaped double bending beam spring element which is made of the common aluminum alloy AW 2024. Generally there is no restriction on the spring element material. The parameters mentioned above are derived from the measured interferometer signal according to the EN ISO 376 standard and are thus traceable to the wavelength of light. The used measurement setup is introduced, measurements of the mentioned parameters are presented and their uncertainty is depicted. It is proved that the setup is suitable to classify double bending beam spring elements according to the highest accuracy Class 00 of EN ISO 376.