Procedure for the determination of torsional deformation relationships for anisotropic materials

Abstract

To calculate the stress-strain and limiting states of anisotropic materials and structural members made of them, one must know Young's modulus (E), shear modulus (G), Poisson's ratios (μ), tensile, compressive, and torsional deformation curves. One of the methods of finding torsional modulus (G) is the computational-experimental method [1-3], which enables one to determine the elastic moduli G 1 and G 2 for on anisotropic material on prismatic specimens. An advantage of the method lies in the use of simple shape of specimens and the possibility of determining G 1 and G 2 from the results of two or three experiments carried out under the same loading conditions (mechanical and thermal loading).Below is proposed a procedure for the determination of torsional deformation relationships for prismatic specimens made of anisotropic materials and construction of deformation curves under these conditions. Its distinction from the procedure reported in [2,3] consists in the utilization and processing of the results of studies [4,5] on the loading of a prismatic bar.The torsion experiments were carried out on specimens made of a carbon/carbon composite (CCC) (Fig. 1) according to the scheme shown in Fig. 2.In the course of experiment, the load P and the rotation angle of specimen ϕ were recorded. Tangential stresses τ, shearing angle h, torsional moduli G (G 1 , G 2 ) were determined using the relations [5]: