Constitutive models aimed at predicting the mechanical response of lead-core bearing devices for passive seismic isolation are discussed in this paper. The study is focused on single-degree-of-freedom models which pro...Constitutive models aimed at predicting the mechanical response of lead-core bearing devices for passive seismic isolation are discussed in this paper. The study is focused on single-degree-of-freedom models which provide a relation between the shear displacement （shear strain） and the shear force （shear stress） in elastomeric and lad-core rubber bearings. Classical Bouc-Wen model along with a numerical procedure for identification of the model constants is described. Alternatively, a constitutive relation introducing a damage variable aimed at assessing the material degradation is also considered.展开更多
铅基快堆(Lead-based Fast Reactor,LFR)是一种极具发展潜力的第四代核能系统,具有良好的非能动安全性和经济性,但在紧急停堆后上腔室内会出现明显的热分层现象,影响堆芯余热排出,从而引发安全问题。本文通过建立简化的1/6上腔室模型,...铅基快堆(Lead-based Fast Reactor,LFR)是一种极具发展潜力的第四代核能系统,具有良好的非能动安全性和经济性,但在紧急停堆后上腔室内会出现明显的热分层现象,影响堆芯余热排出,从而引发安全问题。本文通过建立简化的1/6上腔室模型,采用计算流体力学软件STAR-CCM+开展LFR停堆后上腔室内热分层过程的大涡模拟(Large Eddy Simulation,LES)研究,并基于相关实验数据验证了模型计算的准确性。模拟结果表明,在正常运行工况下,内筒小孔不足以影响上腔室内铅铋共晶合金(Lead-Bismuth Eutectic,LBE)流动;停堆后120 s左右热分层界面形成,400 s左右热分层界面升至内筒顶部,且内筒小孔可显著减缓热分层界面的上升速率。研究成果表明,热分层界面处存在大的温度梯度和不规则涡流,停堆后上腔室内热分层的动态演化及界面特性研究具有重要意义。展开更多
文摘Constitutive models aimed at predicting the mechanical response of lead-core bearing devices for passive seismic isolation are discussed in this paper. The study is focused on single-degree-of-freedom models which provide a relation between the shear displacement （shear strain） and the shear force （shear stress） in elastomeric and lad-core rubber bearings. Classical Bouc-Wen model along with a numerical procedure for identification of the model constants is described. Alternatively, a constitutive relation introducing a damage variable aimed at assessing the material degradation is also considered.
