ANALYSIS OF THIN-WALLED GIRDERS SUBJECTED TO A PULSE TORSIONAL TORQUE

Thin-walled structures, which are primarily meant for static load service conditions may be subjected to transient dynamic loads, which may in turn lead to a more dangerous state of stress in the structure. These transient overloads as compared to steady state (static) loads may deteriorate the mechanical properties of the structural member or lead to its failure. Therefore, analysis of dynamically loaded structures, or the answer to the question at what dynamic loading relative to static loading the structures may be serviceable, is a valid and pertinent issue. This paper deals with thinwalled iso- and/or orthotropic box girders subjected to a pulsed torsional moment causing restrained torsion. Numerical calculations were conducted by means of the ANSYS ® software, a computer suite applying the finite element method [12]. The results were presented in the form of displacement maps and diagrams determining the maximum angle of rotation or deflection of the girder wall as a function of the dynamic load factor, DLF (the ratio of pulse loading amplitude to static critical load).