Mathematical Moment-rotation Models for Steel Connections

The major portion of the overall strength, stiffness, and ductility of a steel structure depends on the performance of its connections. Although there are different structural design philosophies regarding the connections (weak panel-zone and strong panel-zone), each design philosophy considers the connections as key components of steel structures since connections determine whether structural elements are performing to their full capacities; therefore, determining the close-to-actual performance of connections is of vital importance. In this regard, the moment-rotation curve of a structural element is a useful structural design tool due to providing a helpful vision for structural engineers on the performance of any type of structural element. Many researchers have proposed moment-rotation models or used them to predict the flexural performance of structural elements, especially connections of steel structures. Each of these models has its advantages, precision, limits, and downsides. The moment-rotation curve of steel connections is plotted based on an important assumption which states that the steel connections exhibit a semi-rigid performance. This assumption enhances the precision of the design procedures of steel connections. The moment-rotation models are verified experimentally or numerically by various researchers. In this paper, moment-rotation curve models for steel connections focusing on mathematical models are introduced, and their significance is discussed. To set a path clarifying the potential of partially-utilized mathematical concepts in fields of engineering, a new mathematical moment-rotation model based on the concept of fractional derivatives for top and seat angle steel connections is also proposed and verified using the experimental data available in the literature. Furthermore, a point-based system is introduced and used to sort existing mathematical models in an attempt to clarify the precision, costs, and practicality of each model.

کلیدواژه ها:

mathematical-moment-rotation models ، Moment-rotation curve ، semi-rigid steel connections ، flexural performance of steel connections