Assembly type joint based on austenite SMA-steel plate set and martensite SMA bars

Abstract

The invention discloses an assembly type joint based on an austenite SMA-steel plate set and martensite SMA bars. The joint comprises I-shaped steel beams, friction type high-strength bolts, high-strength steel rectangular end plates, dog bone type connecting steel plates, austenite SMA dog bone type connecting plates, austenite SMA dish-shaped springs, the martensite SMA bars and anchoring blocks. The upper and lower flanges of the steel beams are connected with the friction type high-strength bolts through the steel-SMA dog bone type connecting plate set, and webs of the steel beams are connected with the high-strength rectangular end plates through the martensite SMA bars. Furthermore, one end of each martensite SMA bar is fixed to the corresponding anchoring block on the web of each steel beam through a thread, and the other end of each martensite SMA bar is fixed through the corresponding high-strength bolt and a nut, wherein pretightening force is exerted on the other end of eachmartensite SMA bar. With the SMA-steel plate set, the restorability of the joint is improved; with the martensite SMA bars, the energy dissipation capacity of the joint is improved; through simple heating, deformation recovery after an earthquake can be realized; the joint is applied to a steel frame for resisting to the earthquake to obviously improve the earthquake-proof performance of a structure, and lowers repairing difficulty and repairing costs.

Description

Technical field: [0001] The invention belongs to the field of structural engineering, and in particular relates to an assembled node based on austenitic SMA-steel plate groups and martensitic SMA rods. Background technique: [0002] In anti-seismic structures, the traditional design concept of steel frames pursues reliable mechanisms and stable energy dissipation capabilities in order to ensure the survival of structures under earthquakes. Therefore, in order to take advantage of the ductility of the steel frame, the inelastic deformation of the beam ends, column feet, and connection nodes in the structure is generally allowed to occur simultaneously to balance the energy input of strong earthquakes. Although this can achieve the goal of life safety, most members of structures designed according to this concept will undergo inelastic deformation during earthquakes, and there is no recovery, so this structure has a potential overall economic loss. [0003] In order to reduce...

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Problems solved by technology

[0004] Smart materials with self-resetting properties include shape memory alloy (SMA) materials, which have superior shape memory effects and superelastic properties. It will restore the original shape. The latter means that the material can recover its original shape independently after being unloaded after being deformed by the load. These two characteristics correspond to the two phases of the shape memory alloy: low-temperature phase Martensite The bulk phase and the high-temperature phase austenite phase, that is, the low-temperature phase martensite SMA has a full hysteresis curve and has good energy dissipation characteristics. After deformation, it needs to be restored to its original shape by simple heating treatment; the high-temperature phase austenite SMA has Good superelastic properties, it can automatically restore the original shape after unloading after deformation, but its energy dissipation capacity is weak

[0005] In the existing node design, in order to achieve the recoverable characteristics of the structure, most of the nodes are made of austenitic SMA material. Although it can realize self-resetting well, the stiffness of the node is reduced due to its superelasticity. Its energy dissipation capacity is weakened, so in the cyclic action of earthquakes, the overall structure will undergo a large deformation, causing large deformations and irreversible deformations of other components except nodes, which not only gives people a sense of insecurity but also cause a certain loss

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