Investigation of the effect of web opening geometry on static and free vibration behavior of castellated beams

In recent years, the usage of castellated beams in civil engineering, aeronautical engineering, mechanical engineering, and other engineering fields has increased significantly due to their advantages such as being light, inexpensive, high strength, and easy to assemble in practice. Due to these advantages, it is essential to investigate the static and dynamic analyzes of steel castellated beams. In this thesis, the static and free vibration behavior of straight axis castellated steel beams was investigated theoretically by using the three-dimensional finite element method. IPE120, IPE140, IPE160, IPE180, IPE200, IPE220, IPE240 and IPE300 profiles were used in the analyzes and solutions were obtained for 4 different web opening types as circular, square, pentagonal and hexagonal. The effects of boundary conditions (Fixed - Fixed, Fixed - Pinned, Fixed -Free) on the bending and free vibration behavior of beams are also investigated. A tetrahedral element, which is very suitable for modeling irregular geometries, is used in analysis with the finite element method. The material was assumed to be isotropic homogeneous. A total of 240 models were built for static and free vibration analysis, and the mesh was created automatically by the program. First of all, the effects of the web opening type on the static behavior of castellated beams are examined in detail, for this purpose, total displacement values, principal stresses, maximum shear stress values, and Von-mises stresses are obtained for each model. Then, the effect of the web opening geometry on the free vibration response is investigated. Free vibration frequencies of the first ten modes are calculated for each model installed. Amplitude values and mode shapes were also obtained for the considered modes. Based on the obtained results, it has been seen that the web opening geometry, support conditions, and the profile type used affect the displacements and stress values of the castellated beams. Similarly, these geometric properties and support conditions of castellated beams also affect free vibration frequencies and amplitude values.