Comparison of Accordion Metallic Dampers with Filled Accordion Metallic Dampers Using Polymeric Foam under Axial Cyclic Loading

During the last decades, many researches have been carried out on development of
supplemental passive energy absorption devices especially hysteretic metallic
dampers and different types of them with different capacities and potentials have
been developed. The idea of buckling of thin-walled tubes and the use of this
property was led to develop an accordion metallic damper (AMD) [Motamedi,
Nateghi-Alahi-2007]. This damper utilizes the capability of accordion thin-walled
tube for excitation of axisymmetric concertina buckling mode as a damping
mechanism which in turn increases the amount of dissipated energy.
In this paper filled accordion metallic damper (FAMD) is suggested and
analytically and experimentally the behavior of AMD's and FAMD's under axial
cyclic loading are investigated and compared. For this purpose, Firstly analytical
studies based on Finite element method and nonlinear dynamic analysis was
performed on FAMD's for the determination of the approximate preliminary
specifications of different polymers for potential use. After specifying the
preliminary material properties, 4 specimens include 2 FAMD's filled by polymeric
foam and 2 AMD's were subjected to dynamic tension and compression actuator
and the effect of filling AMD's by this polymeric foam on the some of important
specifications of damper studied and try to use this method for improving and
developing of AMD's. Based on the results obtained using the appropriate filling
inside the AMD's is a suitable technique for the purpose of improvement the some
of important specifications such as the number of cycles before failure, amount of
dissipated energy and plastic capacity. The effect of interaction between foam and
accordion thin walled tubes play an important role for this purpose especially in
low capacity AMD's.