Nowadays, steel structure has become an indispensable construction material in most industries, and the following is a brief introduction to the method of studying the stability of steel structure, which has certain reference significance.
1. Balance method
That is, the neutral equilibrium method or the static equilibrium method, that is, the method of establishing the equilibrium differential equation according to the stress conditions of the steel structure after the slight deformation has occurred, and then solving it, which is the most basic method for solving the stable ultimate load of the structure. The following five basic assumptions should be met when establishing the equilibrium differential equation: the member is a straight rod of equal cross-section, the pressure always acts along the original axis of the member, the material follows Hooke's law, the component satisfies the flat section assumption, and the bending deformation of the component is small. The balancing method is commonly used in most cases.
2. Power method
That is, the method of causing vibration by subtle interference of the structural system that is already in equilibrium, and the deformation and vibration acceleration of the structure are related to the load that has been acting on the structure. When the load is less than the stable limit load value, the acceleration direction is opposite to the direction of deformation, and if the interference is removed, the motion tends to be stationary, and the structure is in a stable equilibrium stateWhen the load is greater than the stable limit load value, the direction of acceleration and deformation are the same, and even if the interference is removed, the motion is still divergent, and the equilibrium state of the structure is unstable.
3. Energy method
It is an approximate method to solve the stability of bearing capacity, that is, a method to solve the critical load by the principle of conservation of energy and the principle of potential energy station. According to the analysis of the deformation theory, the energy method can generally only obtain an approximate solution of the buckling loadHowever, if the deformation form after buckling can be known in advance, it is easy to calculate it in this way to obtain an accurate solution. In addition, in general, the principle of total potential energy standing can be used to solve the buckling load, while the stability of the post-buckling equilibrium can be analyzed by using the principle of minimum total potential energy.