Dynamic Testing of a Full Scale Highway Truss: Hammer Excitation (location 33, direction Y)

The truss was excited with hammer excitation to simulate impact test excitation. The modal sledge hammer (PCB 086D50) with softer red tip is used. The hammer hit location for this test was at node 33 in the vertical Y direction. For each of the test configurations, data was collected for approximately 15 hits. In six of the tests, only a single direction (X, Y or Z) and either front of back panel were instrumented with 23 sensors. The seventh test was performed with the 18 sensors attached only on the lower chords front chord at six location in all 3 directions. Hence, data from this test was used to stitch together the other six tests to obtain complete 3 dimensional modal properties of the truss.The deployment of the sensors on the truss for each test is shown. In each test, the first channel was used to measure the input force excitation; modal hammer force or force transducer measurement located at the shaker and the other 23 channels were used to measure output acceleration at the nodes of the structure. Data was collected for 320 seconds at sampling frequencies of 512 Hz for the various sensor configurations. REFERENCE: Documents/Configuration file.doc for full information of test setup, data and damage cases

本桁架采用锤击激励方式，以模拟冲击试验的激励环境。本次试验使用带有柔软红色锤头的模态大锤（modal sledge hammer，PCB 086D50），锤击位置为节点33，沿垂直Y方向施加载荷。针对每种试验配置，均采集约15次锤击的试验数据。其中6组试验仅在单方向（X、Y或Z）以及桁架的正面或背面面板上布置23个传感器。第7组试验仅在3个方向的6个布置位置处的下弦杆正面安装了18个传感器。因此，将该组试验的数据与其余6组试验数据拼接整合，即可获得该桁架完整的三维模态特性。各试验中传感器在桁架上的布置方案详见图示。每组试验中，第1通道用于采集输入激励力信号，包括模态锤击力或振动台处的力传感器（force transducer）测量信号；其余23个通道用于采集结构各节点处的输出加速度信号。针对不同的传感器布置方案，试验采样时长为320秒，采样频率为512 Hz。参考文献：详见Documents/Configuration file.doc文件，以获取试验装置、试验数据及损伤工况的完整信息。