【摘要】 研究了钢筋混凝土梁在各级损伤状态下的锤击试验结果,提取了跨中位移、跨中加速度和跨中附近加加速度响应向上和向下的最大值,分析了三种信号最大值与加载等级之间的关系,通过比较发现,锤击试验梁向下位移最大值、向上加速度最大值、加加速度向上和向下最大值随加载等级增加,整体上表现出单调地上升或下降趋势,因此可以用这三种信号的最大值来判断结构的损伤程度。向下位移最大值与加载等级之间的关系曲线接近直线,因而,在这几种最大值中用向下位移最大值来判断结构的损伤程度效果最好。锤击试验数据的傅立叶变换和时频分析表明,频率与加载等级之间是曲线关系,而向下位移最大值与加载等级之间接近直线关系,因此用梁向下位移最大值判断结构的损伤程度与用频率变化判断结构损伤程度的方法相比较更加方便。更多还原

【Abstract】 From impact excitation vibration tests results of a reinforced concrete beam with increasing damage levels,the upward and downward maximums of displacement and acceleration at the half span point of the beam and the jack near the half span point of the beam can be obtained and the relationships between the three kinds of maximums and load levels are analyzed.By comparing their relationships,it is found that the downward displacement maximums and the upward(acceleration) maximums and the upward and downward jack maximums increase or decrease monotonically with increasing load levels.It can be concluded that such kinds of maximums can be used to estimate the reinforced concrete beam’s damage degree.The downward displacement maximums are nearly linear to the load levels and are the best ones to be used to estimate the damage degree in the four kinds of maximums.The relationships between the fundamental frequencies obtained from either Fourier Transformation or time-frequency analysis and the load levels are curvilinear and the(relationships) between the downward displacement maximums and the load levels are nearly linear,thus,using the(downward) displacement maximums to estimate the damage levels of the reinforced concrete beam is more convenient than using the frequencies.更多还原