| As one kind of metal energy dissipation device, buckling restrained braces has stable energy dissipation characteristics. However, some disadvantages still exist. For example, the use of unbonded materials will lead to difficulty of analyzing in the design and manufacture process, besides the assembly quality and the accuracy is hard to control; the unbonded materials will lose their original function under high temperature; the use of large amounts of grouting mortar will lead to more self-weight and easily lead to crushing failure which may cause the local buckling of braces. Inspired by rigid origami, a type of novel origami buckling restrained braces is proposed in this paper. The finite element simulation and experimental research are conducted. The details are as follows:(1) Several typical forms of creases were summarized in this paper. The import of rigid Miura origami is proposed in this paper. The finite element simulation was conducted for the origami brace. The results show that the ABAQUS software can simulate the low-cyclic loading process of the origami brace well. By comparing origami brace with common brace, it can be found that the overall bending and the folding of typical unit of origami buckling restrained braces occured in compressed process, and the creases can enter the yielding state of energy dissipation in both tension and compression. In addition, the parametric analysis was carried out for the origami brace. The 22 artifacts designed were divided into 5 groups to discuss the influence of the slenderness ratio, folding angle, the angle of basic parallelogram, aspect ratio, width-thickNess ratio on the performance of the hysteretic behavior respectively. The simulation results show that Miura origami has inhibitive effect on buckling of restrained brace, but this inhibiting effect has some requirements on slenderness ratio. When the slenderness ratio is too large, buckling can also happen in origami buckling restrained braces. When the folding angle is smaller than 130°, basic parallelogram angle is about 60°, aspect ratio is smaller than2.73, width-to-thickNess ratio is between larger than 12.5, the brace has good hysteretic curves.(2) Scaled origami buckling restrained brace was simulated, and the design of the test specimen was based on the simulation. Three low carbon steel specimens were designed to verify how folding angle influenced the brace behavior. The experimental results showed that the failure of three specimens were all caused by the fracture of central weld. It is found that the variation tendency of yield displacement, yield load, elastic rigidity, plastic stiffness, pressure imbalance, equivalent viscous damping ratio of three low carbon steel specimens with folding angle agreed well with the results of finite element analogy. To a certain extent, this showed the correctness of the finite element simulation.(3) In order to compare how different steel types influence the hysteretic behavior, two specimens using low yield point steel were designed. Compared with low carbon steel specimens, it’s found that specimens using low yield point steel has smaller yield displacement, better plastic deformation ability and better energy dissipation ability. But its bearing capacity is poorer than the bearing capacity of specimens using low yield point steel.(4) In order to reduce the cost, origami units were set in part of the ordinary square tube and finite element analogy was carried out. The result shows that compared with the braces which are in form of origami units all along the brace, braces with origami units only in part of the whole length has lower yield displacement, larger elastic rigidity and unloading curve stiffness and it has more full hysteresis loop. In addition, how the length of straight section length and thickNess of origami units influence the properties of the braces with origami units only in part of the whole length was studied. |
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