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Fatigue laboratory tests toward the design of SMA portico-braces
G. Carreras,F. Casciati,S. Casciati,A. Isalgue,A. Marzi,V. Torra 국제구조공학회 2011 Smart Structures and Systems, An International Jou Vol.7 No.1
A deeper understanding of the effectiveness of adopting devices mounting shape memory alloy (SMA) elements in applications targeted to the mitigation of vibrations is pursued via an experimental approach. During a seismic event, less than 1000 loading-unloading cycles of the alloy are required to mitigate the earthquake effects. However, the aging effects during the time of inactivity prior to the oscillations (several decades characterized by the yearly summer-winter temperature wave) should be considered in order to avoid and/or minimize them. In this paper, the results obtained by carrying out, in different laboratories, fatigue tests on SMA specimens are compared and discussed. Furthermore, the effects of seismic events on a steel structure, with and without SMA dampers, are numerically simulated using ANSYS. Under an earthquake excitation, the SMA devices halve the oscillation amplitudes and show re-centering properties. To confirm this result, an experimental campaign is conducted by actually installing the proposed devices on a physical model of the structure and by evaluating their performance under different excitations induced by an actuator.
Cohesive zone model을 이용한 접착제 물성평가 : 모드 Ⅰ
이찬주(C.J. Lee),이상곤(S.K. Lee),고대철(D.C. Ko),S. Marzi,박근환(G.H. Park),김병민(B.M. Kim) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
Fracture models and criteria of adhesive with two parameters, namely G<SUB>C</SUB> and σ<SUB>max</SUB>, have been developed to describe the fracture process of adhesive joints. Cohesive zone model(CZM) is a representative two parameter failure criteria approach. In CZM, σ<SUB>max</SUB> is a critical, limiting maximum value of the stress in the damage zone ahead of the crack and is assumed to have some physical significance in adhesive failure. Based on CZM and finite element analysis method, the relationship between fracture load and adhesive properties, as G<SUB>IC</SUB> and(σ<SUB>max</SUB>)<SUB>I</SUB>, was investigated in adhesively bonded joint tensile test and T-peel test. The two parameters in tensile mode loading were evaluated by using the relationship. The value of G<SUB>IC</SUB> evaluated by proposed method showed close agreement with analytical solution for tapered double cantilever beam(TDCB) test which proposed in an ASTM standard.
Fatigue laboratory tests toward the design of SMA portico-braces
Carreras, G.,Casciati, F.,Casciati, S.,Isalgue, A.,Marzi, A.,Torra, V. Techno-Press 2011 Smart Structures and Systems, An International Jou Vol.7 No.1
A deeper understanding of the effectiveness of adopting devices mounting shape memory alloy (SMA) elements in applications targeted to the mitigation of vibrations is pursued via an experimental approach. During a seismic event, less than 1000 loading-unloading cycles of the alloy are required to mitigate the earthquake effects. However, the aging effects during the time of inactivity prior to the oscillations (several decades characterized by the yearly summer-winter temperature wave) should be considered in order to avoid and/or minimize them. In this paper, the results obtained by carrying out, in different laboratories, fatigue tests on SMA specimens are compared and discussed. Furthermore, the effects of seismic events on a steel structure, with and without SMA dampers, are numerically simulated using ANSYS. Under an earthquake excitation, the SMA devices halve the oscillation amplitudes and show re-centering properties. To confirm this result, an experimental campaign is conducted by actually installing the proposed devices on a physical model of the structure and by evaluating their performance under different excitations induced by an actuator.