Effect of High Performance Martial filled in Accordion Metallic Dampers

F. Nateghi, M. Motamedi, A. Ezadi

 

Abstract

During the last decades, many researches have been concerned about the supplemental passive energy absorption devices especially hysteretic metallic dampers and different types of them with different capacities and potentials which have been developed. The idea of buckling of thin-walled tubes and the use of this property lead to the development of an accordion metallic damper (AMD). 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 the energy absorption.
In this research filled accordion metallic dampers (FAMD) are suggested and analytically and experimentally the behavior of AMD’s and FAMD’s under axial cyclic loading 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, 12 specimens include 10 FAMD’s filled by polymeric foam and 2 coresponding 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 the important specification of damper were 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 increasing some of important specification such as the number of cycle before failure, amount of dissipated energy and plastic capacity. In low capacity specimens, filling the specimens is efficient to increase some characteristic of damper such as amount of dissipated energy and also plastic capacity in tension and compression as far as the amount of dissipated enrgy and plastic capacity of system in tension increased about 100% and its plastic capacity increased between 2 until 6 times depends on the amplitude of loading. While in high capacity specimens, filling is an efficient method to increase the strength of AMD’s against low cycle fatigue.
Separation between filler foams and accordion thin-walled tubes because of stress concentration and the generation of contact force is an important parameter of failure in FAMD’s, ofcourse this separation occur less for full fill FAMD’s. Interaction effects between thin-walled tubes and filler foams play an important role Specially in the case of increasing the amount of dissipated energy and the plastic capacity of dampers.

 

Keywords:

Experimental Study, Filled Accordion Metallic Damper, Finite Element, Foam