频率法测试网架结构杆件轴力影响因素的试验研究

Experimental Study on Influence Factor of Frequency Method for Testing Axial Force of the Members of Spacial Truss Structures

大跨度空间网架结构健康检测中杆件轴力无损测试方法至关重要。繁杂和不便现场实施的轴力测试已经影响到健康检测的实用性。探索频率法测试杆件轴力影响因素的变化直接关系到该方法的实用性。针对影响频率法测试空间网架结构杆件轴力的因素研究,能使频率法测试结构杆件轴力时可综合考虑各方面因素,得到精确的数据。通过杆件模型试验分别考虑了杆件轴力、杆件长度、截面及边界条件4因素对杆件自身频率的影响,基于梁弯曲振动理论与数值计算对试验结果进行分析。结果表明,杆件长度、截面及边界条件对杆件自身频率影响较大,杆件轴力对杆件频率影响相对较小,但4个因素对杆件频率影响均呈线性变化且影响程度各不同,可以为频率法测试结构杆件频率时提供参考标准。

Non-destructive axial force test used in the members of spacial truss is highly significant in structural health monitoring.Complex and inconvenient field axial force tests have affected the practicality of the structural health monitoring.To explore the effect factors of frequency method test in the members of spacial truss is directly related to the practicability of the method.The study of effect factors of frequency method can help the method to consider the factors when testing the members of spacial truss.Then,frequency method test can get accurate values of the members of spacial truss.It is very important for bar model test to consider four factors i.e.bar axial force,length,cross section and boundary conditions of the structure in the analysis of frequency method test axial force in the members of spacial truss structure.The analysis of test results based on the beam bending vibration theory and numerical calculation.Model Test shows that bar length,cross section and boundary conditions of the structure have great influence on the frequency of the bars of spacial grid structure.Axial force has a greater influence on the frequency of the members of spacial truss structure,but model test also reveal that the four influencing factors impacting on the bar frequency are a linear change and the degree of influence is different.Therefore,these factors provide a reference standard for frequency method test axial force in the members of spacial truss structure.