Stress and Failure Analysis for Pure Bending Tubes of Cylindrically Orthotropic Composite

Abstract

A novel approach is suggested for the stress and failure analysis for the pure bending of composite tubes made up of layers of angle 0° or 90° together with other arbitrary angles. The new unified coefficients as well as their nonsingular parameters are introduced to overcome the problem in an earlier approach where some of the parameters are singular for a few layer orientations even though the stresses and displacements are nonsingular. It is pointed out that such singular terms in the earlier approach cannot be simply eliminated as the conventional technique for the singular terms in the stresses in the form of polar coordinates. Otherwise, the continuity conditions at the interface between special and ordinary layers cannot be satisfied. In addition, the Tsai-Hill theory is employed for the failure analysis. Since the stresses are explicit, it is possible to exactly predict the failure positions so the calculations can be dramatically saved. The flexural stiffnesses as well as the maximum moments and their failure positions of the tube [90/±45/0] with different thickness of every layer are derived for the application and design in engineering.