International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

This paper presents a two-dimensional numerical algorithm for creep analysis of the elastic beams under uniform torsion. Torque is assumed to be constant during the whole creep process. Tangential stresses are calculated following the warping function distribution. Material creep behaviour is simulated using the effective stress function. Analysis takes in consideration the torque acting on cross-sectional surface independently on the beam length. The proposed numerical algorithm enables the stress analysis to be carried out regardless of the cross-sectional shapes. Viscoelastic effects of the material are modelled by the creep power law formula. Numerical algorithm was developed in Python code and its effectiveness is validated through the benchmark example.

Paper deals with finite element buckling analysis of shear deformable beam-type structures. Displacements and rotations are allowed to be large but strains are assumed to be small. The corresponding equilibrium equations are formulated in the framework of co- rotational description, using the virtual work principle. Displacements and rotations are allowed to be large while strains are assumed to be small. Linear shape functions are used for the axial displacement, while cubic shape functions are employed for transverse displacements and angle of twist. The algorithm is validated on test examples.

This paper presents creep buckling finite element modeling of steel beam-type structure. For beams under sustained loads the loss of stability may occur during a period of exploitation of structure even for loads lower than critical buckling load. For that reason stability is characterized by critical buckling time instead the critical buckling load. The simulation is performed using four nodded Kirchoff- Love theory based shell finite elements. For a space frame, as the test example, critical buckling times are calculated for different levels of applied load, temperature conditions and steel chemical composition.