Modeling of rack components in computer-aided structural analysis – part 1
Modeling of rack components in computer-aided structural analysis – part 2
In the previous issue, the author introduced the topic of modeling thin-walled sections with perforated walls, which are the most commonly used sections for rack uprights. Another noteworthy problem is modeling the connection between the beam (load-bearing crossbar) and the upright.
The final result of the load-bearing capacity analysis of the entire rack structure can depend to a large extent on the adoption of the correct stiffness of this node (moment as a function of rotation). Modeling the connection (hereinafter referred to as the connector for simplicity) in a faithful manner that reflects its actual characteristics is very difficult. This is because the designer would need to have a structural analysis system that possesses an element with variable stiffness. This results from the non-linear characteristic of the connector (variable stiffness, dependent on the rotation angle of the joint). Such a characteristic arises due to plastic deformations in the joint. Therefore, in practice, a simplification is most often used, consisting of linearizing the actual characteristic by replacing the non-linear characteristic with a bi-linear or tri-linear one. The diagrams of all three types of characteristics are shown in Fig. 8, along with the actual characteristic taken during laboratory tests for the purpose of analyzing a specific rack, and the bi-linear characteristic adopted against its background.
The article comes from the magazine “Logistyka” 2002/6.