循环荷载作用下高强铝合金本构关系试验研究

发布时间：2019-04-21 21:35

【摘要】：为研究高强铝合金结构在地震作用下的响应、建立循环荷载作用下高强铝合金的本构关系,对17个7A04高强铝合金试件进行了单调拉伸和多种循环加载制度下的试验。分析了材料的单调性能、滞回性能、宏观破坏形态与电镜下的微观破坏形态。采用Ramberg-Osgood模型拟合了材料的循环骨架曲线,并与单调拉伸曲线做出了对比。试验结果表明:7A04高强铝合金延性较差,破坏突然、断面与拉应力方向成45度;循环荷载下表现出典型的循环硬化现象,在压应变达到1%后,其刚度和强度发生退化;材料在滞回中表现出了混合强化的特征,既包含各项同性强化又包含了随动强化。该高强铝合金在循环荷载作用下的本构关系与单调荷载作用下的本构关系存在较大区别,不能将单调荷载下的本构关系用于循环本构关系中。本文为准确计算高强铝合金结构在地震作用下的响应提供了重要基础与依据。
[Abstract]:In order to study the response of high-strength aluminum alloy structure under earthquake and to establish the constitutive relation of high-strength aluminum alloy under cyclic load, 17 specimens of 7A04 high-strength aluminum alloy were tested under monotonic tension and various cyclic loading systems. The monotone properties, hysteretic properties, macroscopical failure morphology and microcosmic failure morphology under electron microscope were analyzed. The cyclic skeleton curve of the material was fitted by Ramberg-Osgood model and compared with the monotone tensile curve. The experimental results show that the ductility of 7A04 high-strength aluminum alloy is poor, the failure is sudden, the direction of cross-section and tensile stress is 45 degrees, the typical cyclic hardening phenomenon is observed under cyclic loading, the stiffness and strength of the alloy are degraded after the compressive strain is up to 1%. The material shows the characteristics of mixed strengthening in hysteretic process, which includes both isotropic strengthening and follow-up strengthening. The constitutive relation of the high strength aluminum alloy under cyclic load is different from that under monotone load, and the constitutive relation under monotone load can not be used in cyclic constitutive relation. This paper provides an important basis for accurately calculating the response of high-strength aluminum alloy structures under earthquake action.
【作者单位】：清华大学;中国电力科学研究院;
【基金】：高等学校博士学科点专项科研基金(20110002130002) 国家电网公司科技项目(GC71-13-041)
【分类号】：TU311.3;TU395

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