| According to an investigation for seismic catastrophe, more attention was paid to the deformation and damage of the steel structures. It is because of the casualty and property loss in the area where experienced earthquake which contribute to the deformation and damage of the steel or steel-concrete structures. There are several reasons: structural instability-integral or local instability; remaining plastical deformation funtion abatement caused by structural deformation; cracking or abruption which mainly occurs at the node of beams and collums, hence extending to the internal of them. The potential damage attributes to the coincidence of the nature frequency of the structures with the inputting frequency of earthquake unfortunately. However, each of them is closely related to the used materials. In fact, the deformation and damage of structures is the abatement of materials. By using the materials reasonably, the average load can reduce the loss. The loss reflects that there is serious shortage of aseismic property of materials except for the unsuitable structural design, so it provides a new means to develope and design materials. Aseismic engineering need the materials which has high stiffness, high strength and high elastoplasticity, but which is prodox and the traditional materials cannot solve it. In the light of these problems, it is very necessary to develop a metal matrix composite which has a high damped ability. We combine a metal which has high stiffness such as ferrous with a metal which has high damped ability so that they can form a structural composite with high stiffness and high viscoplastic. Hard metal behave elastic deformation so that ensure the stiffness, strength and stability of structure when come across a earthquake while soft metal behave plastic deformation so that absorb the seismic energy, enhance the damping, improve the basic vibrate period of structures. This text put forward the development Fe/Zn aseismic composite for the very first time, doing 3-dimensional finite element analysis for aseismic composites under earthquake by ANSYS software; studying the development Fe/Zn anti-earthquake reunites the experiment foundation of the material, putting forward the Fe/ the Zn anti-earthquake reunites mechanics model and its design projects of the material. In this paper, two metal materials (Q235 steel and pure Zn) were selected and Q235 steel/Zn composite was fabricated by casting technique. The area of hysteresis loops (means of energy) and logarithmic decrement of vibrational amplitude (means of free attenuation) illuminated damping capacity of Q235 steel/Zn. Mechanical properties and interfacial microstructures of the composite were examined by means of tensile and cyclic tests, SEM, EDS, XRD analysis and Vickers-hardness measurement. Micro-crack initiation, propagation of the cracks and tensile fracture character of Q235 steel/Zn composite under axial tension were investigated. The major research efforts of the present study were as follows: (1) It is put forward proposition of developing Fe/Zn anti-earthquake composite firstly. For composite, Fe is contributing to ensure component rigidity, resilience and not occur to big distortion; Plastic distortion of Zn can alter composite vibration cycle, and absorb earthquake energy. (2) Three-dimensional finite element analysis of antiseismic capability of Fe/Zn composite. It is provided to the theories for the system of the new material according to. It is the very first time to study earthquake's responds process of metal layer composite. Observes in "Time Hist Postpro"that biggest stress of Fethe yield intensity, Fe supports load and Zn absorbs energy are proved. (3) It is studied to microcosmic mechanism of Fe/Zn composite plastic consume energy, that macroscopical antiseismic capability of Fe/Zn composite is response of microcosmic mechanism of Fe/Zn composite plastic consume energy is further proved. (4) Tensile and cyclic properties of Q235 steel/Zn composites Stress-strain curve of Q235 steel/Zn composite under tension could be observed between stress-strain curves of Q235 steel and zinc with the same conditions in room temperature. Crosshead speed had nearly no influence on the tress-strain curve of steel/Zn composite. The strength of steel/zinc composite under tension decreased with increasing volume percentage of zinc. Cyclic hardeningprocess of Q235 steel under ±0.5%, ±1%, ±1.5% strains and with 20 cycles was not prominent. However, the maximum tension and compression stresses under ±1%, ±1.5% strains increased after each cycle, suggesting a cyclic hardening process has taken place. The stresses at maximum strains of the same strain, which increased with increasing number of cycles, tended to stabilize with further cycling. The phenomenon of cyclic hardening was more prominent with increasing cyclic strain. (5) Damping property of Q235 steel/Zn composite There were two methods of evaluating damping property of Q235 steel/Zn composite. ①means of energy, The area which was calculated through integrating hysteresis loops reflects damping capacity of materials. The larger the area was, the better the damping capacity became. ②means of free attenuation, owing to the attenuation of systemic vibration through energy dissipation, logarithmic decrement of vibrational amplitude illuminated damping capacity of composite. Because vibrational energy was in direct proportion to the square of amplitude, measuring the ratio of amplitude next to amplitude would work out energy dissipation. A contrast between hysteresis loops of Q235 steel and of steel/Zn composite concluded that, under ±0.5%, ±1% strains the areas of composite were larger than the areas of Q235 steel, which showed great damping property of composite, and under ±1.5% strain the areas were the very reverse, because of the plastic deformation response of zinc in composite. The areas of the compression partial loops were slightly larger than the areas of the tension partial loops in composite at the same strain and cycle. The areas of the full loops gradually tended to stabilize at the same strain with further cycling and subsequently energy dissipation of steel/Zn composite increased with increasing strain. ΔWCΔWTΔWSThe experiments of free attenuation for several different materials have been performed. Results showed that logarithmic decrement of zinc and Q235 steel was about the same and that logarithmic decrement of steel/Zn composite varying with testing direction was better than two simplex materials. Higher decrement of Bdirection than A direction meaned that energy dissipation was fast along B direction. Logarithmic decrement of steel/Zn composite increased with increasing zinc layer. (6) Interfacial microstructure of Q235 steel/Zn composites The interfacial behavior between zinc and Q235 steel were preliminarily revealed by the studies of the interfacial microstructures of Q235 steel/Zn composites. ①It was indicated by SEM analysis that the presence of the banded interface between Q235 steel and zinc was a layer with a width of 40~50μm and flat near steel and serration near zinc were found at the interface. ②It was illuminated by EDS analysis that the content of Fe element distributing in the interface was higher than zinc and that the content of Zn element was much more in the interface than steel but as much as zinc because the diffusion of Zn element towards steel was difficult during the transition from liquid state to solid state. The interface was a diffused layer of Zn element and Fe element. ③According to XRD analysis and Vickers-hardness measurement, interdiffusion reactions between iron and zinc at 550℃should lead to the formation of the following Fe-Zn intermetallic compound: Γ-FeB11BZnB40B, δ-FeZnB7B, FeZnB10 Band ξ-FeZnB13B. The interdiffusion zone consisted of a thin layer of Γand δphases about 10μm in contact with steel, followed by a layer of ξphase in contact with zinc. When Vickers-hardness value of comparing the interface with steel and zinc was high (HV110.42~233.55), it was shown that Fe-Zn intermetallic compound is brittle-hard phase. (7) The fracture analysis of Q235 steel/Zn composite Micro-crack initiation occurred in the interface of Q235 steel/Zn composite under axial tension. The cracks normal to the direction of loading propagated towards zinc with increasing loading. At the same time, there existed micro-crack initiation and propagation in zinc. When micro-cracks connecting with each other formed main-cracks, the growth of main-cracks made zinc rapture. Henceforth, steel alone would support load to rapture. The fracture of steel/Zn composite was made up of tough fracture with dimple and radial pattern characters (steel) andbrittle fracture with river pattern (interface and zinc). This paper was only an initial exploration on numerical simulation, mechanical properties, damping capacity and interfacial microstructures of Q235 steel/Zn composite, as well as the revealing of the process of rupture in composite. Up till now, just primary achievements were made. It was hoped that helpful reference data provided with this paper would redound to the development of damping composites.
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