Stability of compressed metal elements under combined temperature and seismic effects

Аrthquakes cause horizontal and vertical accelerations of the earth's surface, which can lead to the rotation and bending of structures. Columns, as elements of building structures, are subject to seismic forces, which can cause them to twist.

Additionally, one of the most serious threats to buildings and structures during earthquakes is the possibility of fires. Therefore, the issues of studying the stability of compressed metal elements with torsion under temperature effects are very important for seismic regions. The study presents methodologies for analytical and numerical calculations to determine the stability of compressed steel elements and compressed steel elements with torsion under temperature effects.

The calculation analysis is carried out based on numerical simulation methods in the software complex ANSYS Mechanical. A model of a steel column made of S355 steel, designed as a double T-beam, was developed as the test construction. A "Transient Thermal" module type was used for conducting the thermal analysis by applying temperature loading those changes over time to the heated surfaces. The heating of the column is performed according to the standard temperature curve of the gas environment in fire conditions. For analytical calculations, programs were developed for calculations in the PC Matlab. The algorithm for analytically calculating the loss of stability of a compressed element under temperature effects is based on determining the coefficient of reduction of the modulus of elasticity and the heating temperature corresponding to the selected intermediate value of the temperature coefficient of reduced yield strength.

Comparative graphs showing the change in critical temperature due to load action in numerical and analytical calculations, as well as diagrams depicting the decrease in critical force under temperature effects, are provided.

Methodologies for numerical and analytical calculations of the stability of a compressed element with torsion under fire exposure in ANSYS and Matlab have been developed.

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