基于频响函数的高阻尼混凝土悬臂梁试验分析

本文对两根分别为普通C35混凝土悬臂梁及高阻尼混凝土悬臂梁进行了拟静力加载和锤击振动测试的交叉试验。基于结构频响函数,研究高阻尼混凝土悬臂梁基本频率与阻尼比随损伤的变化趋势;考察悬臂梁在不同损伤阶段的裂缝开展情况,建立悬臂梁弯曲动刚度与损伤之间的关系;通过各锤击点不同损伤阶段的频响函数,考察悬臂梁的动刚度退化情况。研究表明:随着控制位移的增加,两悬臂梁构件基本频率均逐渐减小,第一阶阻尼比则先增大后减小;高阻尼混凝土悬臂梁在屈服点后阻尼比显著高于普通混凝土;混凝土悬臂梁动力特性随损伤的关系与悬臂梁裂缝数量、裂缝宽度及塑性发展密切相关。

Experimental study of high damping concrete cantilever beam based on frequency response function

In this paper,the pseudo-static test and hammering vibration test are carried out for two cantilever beams with C35 concrete and high damping concrete respectively.Based on the frequency response function,the trends of the basic frequency and damping ratio of the high damped concrete cantilever beam with damage is studied;the crack development of the cantilever beam in different damage stages is investigated;and the relationship between the bending dynamic stiffness and the damage of the cantilever beam is established;through the frequency response function of each hammering point in different damage stages,the dynamic stiffness degradation of the cantilever beam was investigated.The results show that with the increase of control displacement,the basic frequency of the two cantilever beams decreases gradually,and the first order damping ratio increases at first and then decreases.The damping ratio of high damping concrete cantilever beam after the yield point is significantly higher than that of C35 concrete one.The relationship between dynamic characteristics of concrete cantilever beam and damage is closely related to the number of cracks,crack width and plastic development of cantilever beam.