Strain gauge measurements within the school laboratory practice

A simple technical device has been proposed suitable for exercising strain gauge measurements in introductory courses in tensometry. Its conception has followed from a theoretical strain analysis of the circular thin steel plate loaded by a concentrated central force. The analysis has taken into account a non linearity of the studied strain field and has used a strain tensor for original expression of Poisson's ratio and Young's modulus of the material of the plate. The derivation of analytic expressions of both these constants enabled one to estimate their values by means of the strain gauge measurements. In this way the proposed device demonstrates further application possibilities of the strain gauge method.