基于穿透法的钢桥面板疲劳裂纹超声波检测方法研究

摘要

采用预制裂纹试件对钢桥面板疲劳裂纹的深度和角度两个特征进行超声波检测试验研究,提出一种双探头穿透检测技术,该技术通过测定裂纹尖端信号和最大穿透信号之间的比例关系ωK确定裂纹尖端特征信号,并利用几何关系法计算得到裂纹深度及角度.依据理论计算和平钢板预制裂纹检测试验结果,确定16 m m钢板检测中两种K值探头对应的ωK值,分析该方法的可行性、检测结果的误差大小,以及裂纹宽度对结果的影响.结果表明,对于16 m m钢板,K值为2和0.8时对应 ωK为0.3和0.4.该方法对于裂纹深度及角度的检测具有较好的准确性,且裂纹宽度对于检测结果没有影响.%Ultrasonic testing for the depth and angle of fatigue cracks in steel bridge decks was studied by prefabricated crack specimens .T he double probe penetrating detection technique ,w hich identifies crack tip signal by using the ratio (ωK ) of crack tip signal to maximum transmission signal and calcu-lates the depth and angle of crack by the geometric relationship ,was proposed .According to the theo-retical calculation and the detection test results of flat steel plate with prefabricated crack ,the corre-sponding ωK values under two kinds of K value probe were determined in the test of 16 mm steel plate . And the feasibility of this method ,the error of test results and the influence of crack width on the re-sults were analyzed .The results show that ,for 16mm steel plates ,the ωK values are 0 .3 (K=2) and 0 .4 (K=0 .8) .The testing method for the detection of crack depth and angle has better accuracy and the test results is not affected by crack width .