不同激励模式下桥梁实测阻尼比差异  

Difference of bridge damping ratio under different excitations

作　　者：李湛[1] 李鹏飞[1] 姜震宇[1] 韦韩[1] 

机构地区：[1]交通运输部公路科学研究院,北京100088

出　　处：《振动与冲击》2016年第3期62-67,共6页Journal of Vibration and Shock

摘　　要：收集和分析了国内外学者对结构物阻尼比的实测结果,指出了当前桥梁阻尼比研究成果的局限性。为了弥补当前桥梁阻尼比实测结果匮乏的局限,针对三座典型桥梁进行了阻尼比测试,分析了影响桥梁阻尼比的主要因素。该研究发现:桥梁的阻尼比不是定值,它与桥梁的类型、测试时的激励方式、阻尼比的处理方法、测试环境等有较大的相关性。激励强度越大,测试的阻尼比数值越大。车辆激励作用下的阻尼比数值明显大于环境激励下的阻尼比数值。相同激励模式下,不同的阻尼比处理方法所计算的阻尼比数值差距较大。半功率带宽法计算的阻尼比数值的离散性要大于利用自由衰减法计算的阻尼比。建议桥梁结构阻尼比的测试中需要保证激励的一致性,避免在采样过程中出现激励程度差距较大的激励模式。The data of the damping ratios of structure were collected and analyzed. The limitations on the current researches on the bridge damping ratio were pointed out. In order to make up the limitation of the lack of data of the damping ratios of bridges, three bridges damping ratios were tested. The damping ratios of bridges scatter under the influences of the bridge type, excitation status, calculation method and test environment. With the increase of excitation intensity, the damping ratios of bridges increase significantly. The damping ratio tested under vehicle excitation is larger than that under ambient excitation. Under the same excitation, the damping ratio calculated by the half-power bandwidth method is more widely scattered than that by the free decay method. The test of the bridge damping ratio should be carried out under the same excitation status to ensure the test accuracy.

关 键 词：桥梁工程 阻尼比 激励模式 半功率带宽法 自由衰减法 

分 类 号：U466[机械工程—车辆工程]