To develop a methodology for assessing the strength of ring flanges, research was conducted on the load-bearing capacity of welded pipe joints of varying diameters. The study employed the component finite element method (CFEM) implemented in the IDEAStatiCa Connection software. To verify the obtained results, a numerical experiment was carried out using the ANSYS software package. The investigation considered several types of flange joints made from welded pipes with different diameters. Parameters were selected based on common sections used according to russian Series 3.400-8 (Issue 2). The study found that for all cases, the highest stresses occurred on the flange at the joint with the smaller diameter pipe. The analysis indicated that the CFEM's applicability should be limited to diameter-to-wall-thickness ratios (D1/t1) of up to 40. Beyond this threshold, the CFEM does not accurately predict the strength of the joints due to the significant deformation that occurs in the pipe walls, forming a truncated cone shape at the flange junctions. For practical applications, formulas are proposed to check the strength of ring flanges. These formulas account for the weakening of the plates by bolt holes and provide conservative results. The findings highlight the necessity for additional numerical and physical experiments to refine the methodology for cases with D1/t1 ratios exceeding 75. The proposed approach offers a practical solution for evaluating the strength of ring flanges in welded pipe joints of varying diameters, contributing to the development of relevant engineering standards.

Keywords: load-bearing capacity, ring flanges, welded pipes, assembly joints, strength, component method, numerical experiment

One of the methods for strengthening connections in steel trusses made of cold-formed welded profiles is the use of plate overlays. This article presents their influence on increasing the strength of connections according to the criterion of bearing capacity under compression. The investigations were conducted using the component finite element method. The obtained dependencies of the increase in bearing capacity are demonstrated based on the width and angle of the brace connection. An engineering methodology has been developed to assess the strength of the reinforced connection under compression, utilizing a traditional formula from Russian design standards with the substitution of the thickness of the chord by the equivalent thickness.

Keywords: : reinforcement, connections, cold-formed profiles, bearing capacity, compression