چكيده فارسي :
Link beams of eccentrically braced frames similar to ductile fuses, in addition to avoiding bracing
buckling, attract earthquake energies. Link beamsʹ stiffenershave significant effect in earthquake energy
dissipation and their suitable arrangement, causes increasing the rotation capacity of link beams.
In this investigation, link beams with tubular and I-shaped cross-sections that are similar in area,
moment of inertia, length and stiffener spacing, were compared together and the effect of link beam section
and its stiffeners on the rotation capacityof link beams has been studied. Also in this study, tubular link
beams for different values of flange compactness ratio and web compactness ratio were compared together
and this question has been answered that the flange compactness ratio has more impact on the rotation
capacity of tubular link beams or web compactness ratio?In this investigation, the link beams were modelled
in ABAQUS and in order to loading, AISC-2005 loading protocol was used. In this modelling, shell
elements for flanges, webs and stiffeners have been utilized and also the nonlinear kinematic hardening
plasticity material model has been used.
The result of this investigation indicates that, if link beams with various cross-sections have
geometrical similarity, I-shaped link beams will have approximately two times more rotation capacity than
tubular link beams and it will be more significant with increasing of flange compactness ratio and link
beamlength. Also it can be concluded that flange compactness ratio has more impact on the rotation capacity
of tubular link beams, in a way that for one web compactness ratio, with increasing of flange compactness
ratio, the rotation capacity decreases approximately 69% but for one flange compactness ratio, with
increasing of web compactness ratio, the rotation capacity decreases approximately 36%.
