Pounding between adjacent components and structures has become an important cause of structural damage or even collapse under large excitations such as earthquakes and ship collisions. Shock absorber devices (SAD) are often used to connect the separation gap to reduce the pounding force. However, some shock absorber devices may have residual deformation and need to be repaired or replaced after strong impact. A novel energy absorbing material with residual deformation self-recovery ability, martensitic nickel titanium (NiTi) shape memory alloy pseudo-rubber (SMAPR), is fabricated using three methods in this study. The mechanical properties of SMAPR at room temperature and deformation self-recovery ability of SMAPR material are investigated. After that, the deformation recovery ability of SMAPR specimens even with residual deformation is further tested through heating the specimens in a thermo-control stove. The subsequent mechanical properties after deformation recovery are further investigated to investigate whether degradation in mechanical properties occurs for all kinds of specimens. The experimental results indicate that SMAPR is a kind of material with good potential to develop novel shock absorber devices for engineering applications. Furthermore, theoretical modeling of SMAPR is conducted. Micro-variable-pitch springs in parallel and series, in parallel with a friction component, are employed to model the mechanical behavior of SMAPR. The hysteretic rules are presented and the parameters of this model are derived and identified. Finally, based on micro-variable-pitch springs (MVPS) in parallel and series, a parametric analysis is carried out and the effects of nominal densities, diameters of metal wires, diameters of micro-springs and generalized coefficients of friction of SMAPR are analyzed and discussed.
This paper mainly carries out the preliminary work for the design of an innovative three-way seismic isolator based on the metallic pseudo rubber-silicon rubber (MPR-SR) composite. First, the MPR-SR composite was prepared by adding the SR, a high-molecular polymer, to the MPR, and several MPR-SR specimens of different molding densities were prepared. Next, the specimens were subjected to compression and shear tests under quasi-static and dynamic loads, respectively. Several tests were carried out to reflect how these behaviors are affected by load amplitude, cycle count, loading frequency and molding density. The mechanical properties and damping features between the specimens were compared and analyzed in details. On this basis, the author examined the mechanical properties and SI mechanism of the MPR-SR composite. The results show that the MPR-SR composite has good recoverability under compressive and shear deformations: the composite can recover even if 40% of it has been deformed under compression and 80% under shear load; the hysteretic energy dissipation ability of the composite increases with the molding density; the loading frequency and cycle number have basically no impact on the compressive hysteretic behavior of the composite. To sum up, the MPR-SR enjoys good stiffness and energy dissipation ability, and serves as an excellent material for anti-corrosion, antioxidant three-way seismic isolator.
In reinforced concrete (RC) frame-shear wall structure, the coupling beam needs to yield before the wall limbs are damaged, in order to dissipate the energy of the external load. However, the coupling beam has a limited energy dissipation capacity. Once severely damaged, the coupling beam is difficult to be repaired, which hinders the structural recovery after an earthquake. Considering excellence of metal rubber (MR) in hysteresis energy dissipation and deformation self-reset, this paper changes the energy dissipation mode of the coupling beam by adding an MR damper to the beam. Firstly, the stress-strain curve of MR was obtained through mechanical experiments, and used to construct the constitutive model of the material. Then, the parameters of the damper were designed based on the constitutive model. Next, the MR dampers were installed on the coupling beams of a 12-layer RC frame-shear wall structure. The authors analyzed the time histories of the elastoplastic dynamics of the structure under seismic actions, and calculated the seismic responses like interlayer displacement, absolute acceleration, and base shear force. These parameters were compared with those of the structure without the damper, and the output-deformation envelope curve of the damper on each layer were obtained. In this way, the authors studied how the parameters of the MR damper affect the seismic response of RC frame-shear wall structure. The results show that adding the MR damper to coupling beam can effectively weaken the seismic response of the RC frame-shear wall structure.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.