A NUMERICAL-METHOD FOR TORSIONAL ANALYSIS OF STRUCTURAL ELEMENTS

An efficient numerical algorithm for two-dimensional structural element torsional analysis has been developed. The developed algorithm utilizes a numerical mapping and has no requirement of extended computing power since it does not make use of any stiffness matrix inversion calculation. The scheme preserves the practicability of the finite element method in treating irregular boundaries while it makes use of the simple analysis of the finite difference method. Therefore, a transformed torsional equation in the local system for a structural element consisting of more than one material is derived. For concrete elements, concrete cracking is also taken into consideration. Comparisons of the predicted results with analytical solutions for cross-sections of various shapes indicate that the proposed two-dimensional finite volume approach of the torsional problem is accurate, reliable and fast. Comparisons of the predicted results with available experimental data for reinforced concrete elements indicate that before the occurrence of concrete cracking the results are relatively good. For tested concrete elements having longitudinal bars as reinforcement, the computed torsional rigidity and ultimate torque moment appear to be lower than the measured values. © 1990.