Electrical analogy method for torsion of prismatic shaft

Abstract

This thesis is about the torsion problem of shaft solved by means of the distribution of electrical potential on a conduction medium sheet, this can be done because both systems are analogous. In this thesis, the conducting paper is used as the medium. The conducting paper is cut similar to the cross section of the shaft and then it is supplied on it’s boundary a form of boundary potential similar to the boundary condition of the conjugate function in the torsion problem. The potential distributed on the conducting paper is transformed to conjugate function. Then other values such as shear stress, are calculated from the equation which relate the conjugate function to that value. The experiment may be divided into two parts, the first is concerned with the square and the rectangular cross-section to verity the reliability of the method in normal case. The second is concerned with the I cross-section shaft to investigate the shear stress at the reentrance corner where stress concentration occurs. The values obtained by this meyhod are compared with the analytical value or the approximate values. Experimental results show that the values obtained in normal case including the I cross-section are closed to the analytical values or the approximate values, but in the region where stress concentration occurs, the error is rather high.