空间桁架结构在轴向压力作用下容易发生失稳，采用合理的钢材本构关系进行分析是准确追踪桁架屈曲后行为的有效方法。借助OpenSees软件平台，基于桁架非弹性后屈曲单轴材料本构模型，根据滞回准则，提出了该本构模型新的实现方式；将模型分解为受拉屈服前卸载、受拉屈服后卸载、受压屈服前卸载和受压屈服后卸载4种加卸载路径，基于材料基类编制了空间桁架弹性后屈曲、非弹性后屈曲本构模型，通过算例验证了这些本构模型的正确性，并为如何采用这些模型进行空间桁架结构分析提出了建议。%It is possible to occur buckling for space truss structures. The constitutive model of structural steel is the basis for tracking the buckling behavior of truss members accurately. Therefore, a new method of inelastic post-buckling( IEPB) constitutive model was proposed in OpenSees platform according to the rule of hysteresis. The model was divided into four loading and unloading paths including unloading be-fore yield in tension,unloading after yield in tension,unloading before yield in compression and unloading after yield in compression. A procedure of elastic post-buckling ( EPB) and inelastic post-buckling con-stitutive model of space truss was complied based on material base class. Numerical examples were pres-ented to check the accuracy of the new material constitutive model. Suggestions of using these models to a-nalysis was proposed.
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