Measuring System For Volumetric Strain Measurement In Hydrostatic Pressure Environment

A measuring system is presented to improve the volumetric strain measurement in hydrostatic pressure environment for a hydro-compression loading test. The measuring system consists of a new triaxial extensometer, a novel contactless signal transmission system and an IPT (inductive power transfer) equipment. By the extensometer, triaxial deformations of foam specimen can be measured directly, from which the volumetric strain is determined. Sensitivities of the triaxial extensometer are predicted using a simplified analytical model, and verified through experimental calibrations. To avoid the punching and lead sealing techniques on the pressure chamber for hydro-compression loading and transfer the strain data of the triaxial extensometer effectively, a new modus of contactless differential signaling is developed in this paper for elimination of noise caused by the IPT.