The Use of Proximity Transducers for Local Strain Measurements in Triaxial Tests

A description is given of an instrumentation system suitable for measuring axial and radial strains locally in the central region of a triaxial specimen. The system is primarily intended to measure small strains and is one of several that may be employed to avoid errors associated with conventional measurements. A theoretical assessment is made of the accuracy achieved at strains of up to 0.1%. Experimental results are also presented to illustrate the extent of various random errors.