HRB400Ⅲ级抗震钢筋单轴棘轮行为研究

Methodological System to Describe Uniaxial Ratcheting Behavior of HRB400Ⅲ Aseismic Reinforced Bars

在室温下研究了HRB400Ⅲ级抗震钢筋在非对称循环加载下的棘轮行为,分析了应力幅、平均应力和应力速率对材料棘轮行为的影响。结果表明:棘轮应变会随着应力幅或者平均应力的增加而增加;在低应力幅下,晶内背应力会阻碍棘轮应变的积累;棘轮应变随着应力速率的增加而相应增加;然而,高应力速率下,材料的疲劳寿命会增加。在非对称循环加载中,应变能密度会随着应力幅和平均应力的增加而增加;材料在循环载荷下表现出明显的循环硬化特征。

An experimental study was carried out on the cyclic ratcheting of HRB400Ⅲ aseismic reinforced bars subjected to asymmetric cyclic loading at room temperature.The effects of stress amplitude,mean stress and stress rate on HRB400Ⅲ aseismic reinforced bars were investigated completely.The experimental results indicated that increase of either stress amplitude or mean stress increased the ratcheting strain accumulated in the material.Under low stress amplitude,the intragranular back stress would hinder the accumulation of ratchet strain,meanwhile,ratcheting strain increased with the increase of stress rate.However,at high stress rate,the fatigue life of the material increased.During asymmetric cyclic loading,the strain energy density increased with the increase of stress amplitude and average stress.The material showed obvious cyclic hardening characteristics under cyclic loading.