Hysteretic seismic dissipators C.M.M. ISTER-BEND
C.M.M. ISTER is the series of seismic dampers produced by C.M.M. that exploit the dissipative capacity of suitably shaped steel elements.
The ISTER-BEND model consists of "sickle-shaped" dissipative elements that work in opening-closing thus ensuring the complete plasticization of the section for the applied bending moment: the consequent dynamic elasto-plastic behavior ensures the maximum seismic displacement and provide the required seismic energy dissipation.
The ISTER-BEND model consists of "sickle-shaped" dissipative elements that work in opening-closing thus ensuring the complete plasticization of the section for the applied bending moment: the consequent dynamic elasto-plastic behavior ensures the maximum seismic displacement and provide the required seismic energy dissipation.
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The dissipative elements can be coupled to a mobile support or be arranged in a restraining system (damping restraints for bridges or dissipative bracing for buildings), to provide damping along one or more directions of movement.
The typical force-displacement behavior of the first load branch can be seen as bilinear, as shown in the following diagram where the nominal behavior is compared with the experimental one:
The typical force-displacement behavior of the first load branch can be seen as bilinear, as shown in the following diagram where the nominal behavior is compared with the experimental one:
The typical force-displacement ratio of an entire cyclic opening-closing test is shown in the following figures (nominal behavior and experimental graph). The entire cyclic behavior can provide a damping capacity of over 40%.
* the value of Fu may be slightly different in opening and closing due to the heat sink configuration.
The high initial stiffness of the element (with low displacements) is useful to guarantee a rigid behaviour in service (static condition, wind load).
The maximum displacements obtainable with this type of damper are of the order of +/- 300mm.
The high initial stiffness of the element (with low displacements) is useful to guarantee a rigid behaviour in service (static condition, wind load).
The maximum displacements obtainable with this type of damper are of the order of +/- 300mm.
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