Comparation of Model and Experimental Results of Elastoplastic Structure Loaded with Bending Moment and Torsion

Experimental testing and numerical analysis were conducted on steel structure with 20 × 20 mm rectangular section loaded with combination of bending moment (M) and torsion (T), used to validated the previous study. Specimen used in the research was cantilever grid beam with fixed constraint at the end of the beam. The specimen was incrementally loaded parallel with gravity direction until failure occurred. Load, displacement and strain at observed point were recorded to analyze failure criteria based on Von Mises criteria. Numerical model using DIANA was used to analyze further the internal forces and stress distribution at the beam structure. 3D solid model was used for the numerical analysis in order to represent the experimental results. Experimental and numerical analysis results were in good agreement compared to the previous study. The experimental strain data shows that plastic joints formed gradually in one location and followed in other locations. Analysis using Von Mises criteria shows that the yield of the structure was significantly affected by bending with proportion of ± 90%. Numerical model located the same position of plastic joints compared to experimental. The stress distribution shows that the maximum stress is located at the vertical outer side of section which indicated that the bending stress is dominant.