An appropriate constitutive model to characterize the mechanical behavior of fiber reinforced concrete (FRC) plays a critical role in accurate prediction of structural performance. In this study, an elastoplastic damage constitutive model is developed for hybrid steel-polypropylene fiber reinforced concrete (HFRC), which can predict the versatile mechanical responses of HFRC as a result of various hybrid fiber inclusions. For plasticity growth, the Willam-Warnke five-parameter failure envelope is modified in the effective stress space to govern the yield condition of HFRC, while a nonlinear Drucker-Prager type plastic potential function is proposed to control the non-associated plastic flow. Regarding the damage evolution, the damage criterion and evolution laws are established in the Cauchy stress space, in which the plastic hardening and unilateral behaviors are taken into consideration. Upon two parallel integration algorithms to describe the development of plasticity and damage, as well as the identification of fiber-dependent parameters, the proposed model is numerically implemented and then validated by the experimental results from available research. The comparisons between the numerical predictions and the test results at both material scale and structural scale solidly demonstrate the capacity of the model in capturing the main features of HFRC when subjected to different loading paths.

一个合适的本构模型来表征纤维增强混凝土 (FRC) 的力学行为在准确预测结构性能方面起着至关重要的作用。在这项研究中，为混合钢-聚丙烯纤维增强混凝土 (HFRC) 开发了弹塑性损伤本构模型，该模型可以预测各种混合纤维夹杂物导致的 HFRC 的多功能力学响应。对于塑性增长，在有效应力空间中修改 Willam-Warnke 五参数失效包络以控制 HFRC 的屈服条件，同时提出非线性 Drucker-Prager 型塑性势函数来控制非关联塑性流动。关于损伤演化，在柯西应力空间建立损伤判据和演化规律，其中考虑了塑性硬化和单边行为。通过两个并行积分算法来描述塑性和损伤的发展，以及纤维相关参数的识别，所提出的模型在数值上实现，然后通过现有研究的实验结果进行验证。数值预测与材料尺度和结构尺度测试结果的比较充分证明了模型在不同加载路径下捕捉 HFRC 主要特征的能力。所提出的模型在数值上实现，然后通过现有研究的实验结果进行验证。数值预测与材料尺度和结构尺度测试结果的比较充分证明了模型在不同加载路径下捕捉 HFRC 主要特征的能力。所提出的模型在数值上实现，然后通过现有研究的实验结果进行验证。数值预测与材料尺度和结构尺度测试结果的比较充分证明了模型在不同加载路径下捕捉 HFRC 主要特征的能力。