Mechanical properties and theoretical modeling of self-centering shape memory alloypseudo-rubber

Abstract

Pounding between adjacent components and structures has become an important cause ofstructural damage or even collapse under large excitations such as earthquakes and shipcollisions. Shock absorber devices (SAD) are often used to connect the separation gap toreduce the pounding force. However, some shock absorber devices may have residualdeformation and need to be repaired or replaced after strong impact. A novel energyabsorbing material with residual deformation self-recovery ability, martensitic nickeltitanium (NiTi) shape memory alloy pseudo-rubber (SMAPR), is fabricated using threemethods in this study. The mechanical properties of SMAPR at room temperature anddeformation self-recovery ability of SMAPR material are investigated. After that, thedeformation recovery ability of SMAPR specimens even with residual deformation isfurther tested through heating the specimens in a thermo-control stove. The subsequentmechanical properties after deformation recovery are further investigated to investigatewhether degradation in mechanical properties occurs for all kinds of specimens. Theexperimental results indicate that SMAPR is a kind of material with good potential todevelop novel shock absorber devices for engineering applications. Furthermore,theoretical modeling of SMAPR is conducted. Micro-variable-pitch springs inparallel and series, in parallel with a friction component, are employed to model themechanical behavior of SMAPR. The hysteretic rules are presented and the parametersof this model are derived and identified. Finally, based on micro-variable-pitchsprings (MVPS) in parallel and series, a parametric analysis is carried out and theeffects of nominal densities, diameters of metal wires, diameters of micro-springsand generalized coefficients of friction of SMAPR are analyzed and discussed.