基于叩诊法的单排多螺栓钢梁柱节点松动检测方法

Percussion-based bolt loosening detection method in a single-row multi-bolted steel beam-column joint

叩诊法是指利用力锤敲击待测结构振动发声,通过声音特征诊断结构有无异常的一种检测方法。基于叩诊法的螺栓松动检测是近年来的研究热点之一。现有研究多关注单螺栓松动问题,而工程中常采用多螺栓连接方式,因此现有的研究方法无法满足工程多螺栓松动检测需求。以一单排多螺栓钢结构梁柱节点为研究对象,提出了一种基于叩诊法的多螺栓松动快速检测方法。首先通过短时傅里叶变换和二值化处理提取节点中各螺栓的叩诊声音特征向量,再计算各螺栓松动工况与基准工况特征向量间的欧式距离以量化松动特征。结合所有螺栓松动特征值构造标准化松动指标衡量节点松动程度后,对比各螺栓松动特征值与其基准值的差异性大小识别松动螺栓。研究结果表明,研究方法可快速准确地识别多螺栓节点中的松动螺栓,进一步提升叩诊检测方法在工程中的应用潜力。

The percussion-based method refers to a detection technique that utilizes a hammer to percuss test structures to produce vibration and sound,and diagnoses any abnormalities in structures based on sound features.Percussion-based bolt loosening detection has been one of the hot research topics in recent years.Most existing studies focus on the issue of single bolt loosening,while multi-bolt connections are commonly used in engineering applications.Therefore,current methods can not meet requirements for multi-bolt loosening detection in engineering.This paper proposes a fast percussion-based multi-bolt loosening detection method,using a single-row multi-bolted steel beam-column joint as the research object.Firstly,characteristic vectors of percussion sound of each bolt within the joint are extracted by short-time Fourier transform and binarization processing.Then,the Euclidean distances between characteristic vectors of each bolt under the loosening cases and under the reference case are calculated to quantify loosening characteristics.Normalized loosening indexes are subsequently constructed by combining loosening characteristic values of all bolts to measure loosening degree of the joint.Finally,the loosened bolts are identified by comparing the difference between loosening characteristic values and baseline value of each bolt.Experimental results show that the proposed method can rapidly and accurately identify loosened bolts in the joint,and further enhance the potential of percussion detection method in engineering application.