Measurement of Modulus of Rigidity G by means of Twisted Square Plates

抄録

This paper deals with the measurement of rigidity G and the shear stress-strain relations by means of the twisted square plate, which is a square plate subjected to four vertical loads of the same intensity, two of them acting downward at the ends of one diagonal, and the remaining two holding upward at the ends of the other diagonal. In this type of loading the two principal bending moments have equal and opposite signs and the deflection becomes anticlastic. And there exists an instability limit in transit from anticlastic to synclastic deformation of square plates. The authors have made a study of the effects of shapes and sizes of specimens on the instability limit and shown some typical examples of measurement of G and τ-γ relations in half-hard aluminium plates. It has been revealed that the limits of such instability initiation are to be used as basic data for determination of the limit of application of this method.