The Plastic-elastic Finite Element Analysis For The Longitudinal Supported Frame Construction Of The Main Thermal Power Plants

The frame structure is used widely in main thermal power plants. The high-degree and large-span structures are usually used to meet the functional requirements of the plants. At the same time, inserting energy supporting in the framework of the columns is used to meet the requirements of the static and seismic design. Some scholars did related theoretical and design research about the vertical frame structure. Research interests focus on the pseudo-static and dynamic load test of the simplified structural model. The Numerical simulation of mechanical behavior of the structure is less. There was not so depth study of how to determine the optimal position in the structure. In the ANSYS software, this paper anal sizes the simplified model of the main plant in some electricity generating station by using of the elastic and plastic finite element method. The research has important theoretical and practical engineering value.Supporting structure of side span and supporting structure of mid-span were analyzed with finite element simulation in this paper. It included developing process and distribution characteristics of structure crack, hysteretic behavior, ductility, stiffness, lateral displacement of every floor, force condition of steel support and energy dissipation device. The result shows that bottom beam affected by low-frequency cycle load generated crack first, then column base generated crack followed increasing load. The first plastic hinge appeared in left column base of side span support structure, but it appeared in right column base of no support structure of side span. Hysteretic curve shows shuttle shape before entering yield situation and toxoplasma after entering yield situation. It also shows stiffness degradation. Support obviously improves stiffness for side span structure. Initial stiffness was increased by 170% and yield stiffness was increased by 110%. Stiffness of side span is higher than mid-span. Initial stiffness is more than 25% and yield stiffness is more than 17%. Story drift of second and third is larger than bottom. Energy dissipation brace undertook horizontal shear as much as approximate as energy dissipation device, but displacement was different. Displacement of energy dissipation device is energy dissipation brace 2 to 5 times. Structure mechanical behavior affected by brace and position of brace is different.According to the results, this article presents relationships about relative rigidity and relative loads of three structures. Design proposals to arrangement of supporting are also proposed. It has great theoretical significance and certain value in engineering.