



Comparison of calculation results for beam finite element model of the structure and model from twodimensional elementsIn the determination of stressedlydeformed state of solid building structures using a finite element method, different approaches to building of finite element models may be used. In each particular case, the degree of model elaboration is selected on the basis of conditions formulated in the statement of problem. Consider two different approaches to building of a solid finite element model by example of cover structure of Odintsovo Volleyball Center. determination of local stresses at the connection points of bearing structures. The cover of the Center is the system of cross girders from rollformed welded closed sections.
Connections of bearing elements in the joints are realized by two methods: edge lines of rollformed welded sections are welded to the plates, and these welded sections are joined together with highstrength bolts.
For this problem, two finite element models of the structure cover were developed: 1. Beam finite element model
2. The second finite element model is formed with the use of twodimensional elements (SHELL elements). In this case, solid geometry of sections and structural features of connection points with account taken of thicknesses of all structural elements are modeled in sufficient detail. Subject to importance of the structure, smaller details may be modeled (nonstandard bolted joints, welded joints, etc). Modern computers make it possible to calculate a complete model of the structure allowing the designer to see the picture of stressed state of the structure in its entirety.
For both finite element models, calculations were made with loading of the structure by specified forces. Both geometric and physical nonlinearity was taken into consideration.
The calculations showed coincidence of deflections in the structure with accuracy of 2% and coincidence of respective stresses in the bearing beams with accuracy of less than 3%. This makes it possible to draw a conclusion on adequacy of the models: the beam finite element model and the finite element model from twodimensional elements. However, such coincidence of stresses is observed only in a significant distance from beam ends, while the values and nature of stress distribution at the connection points of the beams received in the calculation for detailed SHELL model are significantly different from the stresses which can be observed with the application of beam theory. In addition, it seems impossible to detect some local stress surges in the beam model. The examples of local stress surges that cannot be detected by beam model calculation are described below.
Hexa Company to order of the State Unitary Enterprise of the Moscow Region, Mosoblstroyproject Design Institute, 2006 

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