- Simple plastic analysis method.
The properties of plastic hinges. The full-section yield conditions of bending members and compression-bending members. When the section meets the yield conditions, it is considered to be in This section forms a plastic hinge. The sections near the actual plastic hinge have developed a certain degree of plasticity, forming a plastic region. In order to simplify the calculation, it is considered that the plastic zone is only concentrated on the plastic hinge section, and the other parts of the rod remain elastic. When under the action of external load, a certain section of the rod reaches the plastic moment elbow. In the future, this section can not only transmit the bending moment, but also allow any amount of rotation in the direction of the moment action, but cannot transmit bending greater than M, Moment. When the load is reversed (or unloaded), the plastic hinge recovers elasticity and can transmit the bending moment in the opposite direction, but cannot rotate arbitrarily. Only when the bending moment in the opposite direction reaches the plastic bending moment, the reverse plastic hinge will be formed.
- The basic concept of plastic design Steel has good ductility. Under the condition of ensuring that the space frame engineering components do not lose local stability and lateral stability, plastic hinges with sufficient rotation capacity can be formed in several parts of the statically indeterminate grid engineering , Cause the redistribution of the internal forces of the space frame engineering, thereby exerting the potential of each part of the space frame engineering. This plastic design method that uses the ultimate bearing capacity of the entire space frame project as the ultimate state of the space frame project has the following advantages. (1) Compared with the usual elastic design method, it can save steel (10%~15%) and reduce Cost;
(2) A more intuitive estimation of the safety of the entire space frame project.