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空间网格结构在地震作用下,材料塑性发展严重,材料损伤将对结构的性能产生重要影响。为得到能够精确反应空间网格结构在复杂荷载作用下材料损伤累积的本构模型,设计空间结构常用圆钢管进行三向加载试验,通过不同的加载方案考察试件的空间滞回特性;编制考虑损伤和裂纹效应的ABAQUS用户子程序对试验进行数值模拟,利用试验曲线与数值曲线的符合程度来拟合考虑损伤的材料本构方程中各系数,并通过最小二乘法拟合得到圆钢管考虑损伤的材料本构模型;用此本构模型对试验试件进行模拟。结果表明:数值曲线和试验曲线吻合良好,建议的本构方程是较为准确的,说明所编制的接口子程序可用于复杂结构的分析,应用此本构模型详细考察了单层球面网壳在地震作用下的各项响应,结果表明考虑累积损伤结构的失效极限荷载显著降低。
Space grid structure Under the action of earthquake, material plasticity develops seriously, material damage will have an important influence on structure performance. In order to get the constitutive model which can exactly reflect the damage of the material under the complex load, the three-direction loading test of round steel pipe is often used to design the space structure and the space hysteresis of the test piece is investigated through different loading schemes. Damage and crack effects of ABAQUS user subroutine to test the numerical simulation, the use of test curves and numerical curves fit to consider the material damage constitutive equations of the coefficients, and through the least squares method to get the round tube to consider the injury Of the material constitutive model; using this constitutive model to simulate the test specimen. The results show that the numerical curve is in good agreement with the experimental curve, and the proposed constitutive equation is more accurate. It shows that the interface subroutine can be used for the analysis of complex structures. Using this constitutive model, The results show that the ultimate load of failure considering the cumulative damage structure is significantly reduced.