Steel frames analyzed by use of advanced displacement mode‐based beam and joint elements

This paper addresses a linear elastic methodology for analysis of thin‐walled steel frames. The analysis is based on structural meaningful displacement modes that considerably reduce the number of degrees of freedom needed compared to a similar analysis using shell finite elements. The methodology allows the use of an adequate reduced number of higher order displacement modes. The methodology uses advanced beam elements to model the major structural elements within the frame and advanced joint elements to model the connections between the beam elements. Each joint element is a super element modeled by use of other finite elements such as shell elements. This allows the user to model virtually any geometry of the connection. Furthermore, the advanced beam element is formulated based on a linear combination of structural meaningful displacement modes belonging to each individual beam. Since the methodology is based on displacement modes of the (advanced) beams, it is possible to extract and identify critical displacement patterns for the frame as well as for each beam and joint within the frame. This gives the designer an in‐depth understanding of the behavior of the frame and hence a powerful tool to optimize its design.