Issue 40

Z. Zhang et alii, Frattura ed Integrità Strutturale, 40 (2017) 149-161; DOI: 10.3221/IGF-ESIS.40.13 160 energy and the thermal convection energy is larger and larger as the opening ratio increases with the same displacement load. Also, the thermal energy due to thermal dissipation and convection holds a very large percentage of the total work, which indicates that the thermal energy is very important in plastic deformation and local damage deformation for coupling beam damper during low cycle fatigue test. Moreover, the plastic energy also holds a large part of the total energy. In sum, under the same displacement load, as the opening ratio increases, the bearing capacity and the hysteresis energy would decrease, while the ratio of thermal energy would increase. a. SPA b. SPB Figure 12 : Plastic dissipation energy of SPA and SPB during the cyclic loading process. C ONCLUSION ased on the traditional hysteresis experiments of metal dampers, and by applying Infrared thermal camera to compare the temperature rise of two different kinds of coupling beam dampers during the experiments. The plastic damage energy and the relationship between different energies could be achieved according to energy balance equation, and the following conclusions could be achieved: 1. Based on the metal damper of SPA, out-of-plane phenomenon would appear easily for smaller opening ratio during the hysteresis process so as to cause the degeneration of stiffness along the loading direction under the case of not obvious yield. 2. With the same opening ratio and same displacement load condition, the hysteresis energy dissipation performance of SPA is much better than SPB. 3. The opening ratio could influence the temperature rise. Specifically, the rapid temperature rise would appear earlier for larger opening ratio. 4. During the hysteresis process of metal beam damper, the thermal energy is produced along the plastic damage and holds a very important part of total energy. The plastic energy is an important factor that deduces fatigue damage and irreversible change of microstructure. A large part of plastic deformation energy would appear in the type of thermal energy so that the temperature rises which in turn reflects microstructure evolution. A CKNOWLEDGEMENTS e would like to thank the financial supports of the National Natural Science Foundation of China (No.91315301-12 and No.51601175). R EFERENCES [1] Paulay, T., Simulated seismic loading of spandrel beams. Journal of the Structural Division, ASCE97 (ST9) (1971) 0 2 4 6 8 10 0.0 5.0E3 1.0E4 1.5E4 2.0E4 2.5E4 3.0E4 SPB10 SPB15 SPB20 SPB25 （ ） Energy dissipation of plastic accumulative D J Displacement(mm) 0 2 4 6 8 10 0.0 5.0E3 1.0E4 1.5E4 2.0E4 2.5E4 3.0E4 SPB10 SPB15 SPB20 SPB25 （ ） Energy dissipation of plastic accumulative D J Displacement(mm) B W