【摘要】 讨论有限变形和小变形假设下本构关系的区别,并将其运用于混凝土的弹＿粘塑性本构关系研究,提出了一个应变率相关的动态力学模型·　模型基于Ottosen的4参数屈服准则,分别考虑混凝土在硬化阶段和软化阶段加载面的不同变化规律,建立冲击荷载下的混凝土本构关系·　该模型可以应用于冲击载荷下混凝土材料响应的模拟·　引进Green＿Naghdi客观率建立有限变形的混凝土模型·　根据大量实验结果对应变率和材料强度的关系提出合理假设,使模型可以反映混凝土大变形的动态力学行为,为相关工程问题的研究提供有益的思路和有效的工具·更多还原

【Abstract】 The differences between finite deformation and infinitesimal deformation are discussed. They are exercised on elasto_viscoplastic constitutive relations of concrete. Then, a Rate_dependent mechanics model was presented on the basis of Ottosen’s four_parameter yield criterion, where different loading surface transferring laws were taken into account, when material was in hardening stage or in softening stage, respectively. The model is well established, so that it can be applied to simulate the response of concrete subject to impact loading. Green_Naghdi stress rate was introduced as objective stress rate. Appropriate hypothesis was postulated in accordance with many experimental results, which could reflect the mechanical behaviour of concrete with large deformation. Available thoughts as well as effective methods are also provided for the research on related engineering problems.更多还原